field_manager.F90

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!> @defgroup field_manager_mod field_manager_mod
!> @ingroup field_manager
!> @brief Reads entries from a field table and stores this
!! information along with the type  of field it belongs to.
!!
!> This allows the component models to query the field manager to see if non-default
!! methods of operation are desired. In essence the field table is a
!! powerful type of namelist. Default values can be provided for all the
!! fields through a namelist, individual fields can be modified  through
!! the field table however.
!!
!> @author William Cooke
!!
!! An example of field table entries could be
!! <PRE>
!!              "tracer","atmos_mod","sphum"
!!
!!              "tracer","atmos_mod","sf6"
!!              "longname","sulf_hex"
!!              "advection_scheme_horiz","2nd_order"
!!              "Profile_type","Fixed","surface_value = 0.0E+00"/
!!
!!              "prog_tracers","ocean_mod","age_global"
!!              horizontal-advection-scheme = mdfl_sweby
!!              vertical-advection-scheme = mdfl_sweby
!!              restart_file = ocean_age.res.nc
!! </PRE>
!!
!! The field table consists of entries in the following format.
!!
!! The first line of an entry should consist of three quoted strings.
!!
!! The first quoted string will tell the field manager what type of
!! field it is.
!!
!! The second quoted string will tell the field manager which model the
!! field is being applied to.
!! The supported types at present are
!!<PRE>
!!      "coupler_mod" for the coupler,
!!      "atmos_mod" for the atmosphere model,
!!      "ocean_mod" for the ocean model,
!!      "land_mod" for the land model, and,
!!      "ice_mod" for the ice model.
!!</PRE>
!! The third quoted string should be a unique name that can be used as a
!! query.
!!
!! The second and following lines of each entry are called methods in
!! this context. Methods can be developed within any module and these
!! modules can query the field manager to find any methods that are
!! supplied in the field table.
!!
!! These lines can be coded quite flexibly.
!!
!! The line can consist of two or three quoted strings or a simple unquoted
!! string.
!!
!! If the line consists two or three quoted strings, then the first string will
!! be an identifier that the querying module will ask for.
!!
!! The second string will be a name that the querying module can use to
!! set up values for the module.
!!
!! The third string, if present, can supply parameters to the calling module that can be
!! parsed and used to further modify values.
!!
!! If the line consists of a simple unquoted string then quotes are not allowed
!! in any part of the line.
!!
!! An entry is ended with a backslash (/) as the final character in a
!! row.
!!
!! Comments can be inserted in the field table by having a # as the
!! first character in the line.
!!
!! In the example above we have three field entries.
!!
!! The first is a simple declaration of a tracer called "sphum".
!!
!! The second is for a tracer called "sf6". In this case a field named
!! "longname" will be given the value "sulf_hex". A field named
!! "advection_scheme_horiz" will be given the value "2nd_order". Finally a field
!! name "Profile_type" will be given a child field called "Fixed", and that field
!! will be given a field called "surface_value" with a real value of 0.0E+00.
!!
!! The third entry is an example of a oceanic age tracer. Note that the
!! method lines are formatted differently here. This is the flexibility mentioned
!! above.
!!
!! With these formats, a number of restrictions are required.
!!
!! The following formats are equally valid.
!!<PRE>
!!      "longname","sulf_hex"
!!      "longname = sulf_hex"
!!      longname = sulf_hex
!!</PRE>
!! However the following is not valid.
!!<PRE>
!!      longname = "sulf_hex"
!!</PRE>
!!
!! In the SF6 example above the last line of the entry could be written in the
!! following ways.
!!<PRE>
!!      "Profile_type","Fixed","surface_value = 0.0E+00"/
!!      Profile_type/Fixed/surface_value = 0.0E+00/
!!</PRE>
!!
!! Values supplied with fields are converted to the various types with the
!! following assumptions.
!!<PRE>
!! Real values : These values contain a decimal point or are in exponential format.
!!    These values only support e or E format for exponentials.
!!    e.g. 10.0, 1e10 and 1E10 are considered to be real numbers.
!!
!! Integer values : These values only contain numbers.
!!    e.g 10 is an integer. 10.0 and 1e10 are not.
!!
!! Logical values : These values are supplied as one of the following formats.
!!    T, .T., TRUE, .TRUE.
!!    t, .t., true, .true.
!!    F, .F., FALSE, .FALSE.
!!    f, .f., false, .false.
!!    These will be converted to T or F in a dump of the field.
!!
!! Character strings : These values are assumed to be strings if a character
!!    other than an e (or E) is in the value. Numbers can be suppled in the value.
!!    If the value does not meet the criteria for a real, integer or logical type,
!!    it is assumed to be a character type.
!!</PRE>
!! The entries within the field table can be designed by the individual
!! authors of code to allow modification of their routines.
!!

!> @addtogroup field_manager_mod
!> @{
module field_manager_mod
!TODO this variable can be removed when the legacy table is no longer used
#ifndef MAXFIELDS_
#define MAXFIELDS_ 250
#endif

!TODO this variable can be removed when the legacy table is not longer used
#ifndef MAXFIELDMETHODS_
#define MAXFIELDMETHODS_ 250
#endif

!
! <CONTACT EMAIL="William.Cooke@noaa.gov"> William Cooke
! </CONTACT>
!
! <REVIEWER EMAIL="Richard.Slater@noaa.gov"> Richard D. Slater
! </REVIEWER>
!
! <REVIEWER EMAIL="Matthew.Harrison@noaa.gov"> Matthew Harrison
! </REVIEWER>
!
! <REVIEWER EMAIL="John.Dunne@noaa.gov"> John P. Dunne
! </REVIEWER>

use    mpp_mod, only : mpp_error,   &
                       FATAL,       &
                       NOTE,        &
                       WARNING,     &
                       mpp_pe,      &
                       mpp_root_pe, &
                       stdlog,      &
                       stdout,      &
                       input_nml_file
use    fms_mod, only : lowercase,   &
                       write_version_number, &
                       check_nml_error
use fms2_io_mod, only: file_exists, get_instance_filename
use platform_mod, only: r4_kind, r8_kind, FMS_PATH_LEN, FMS_FILE_LEN
#ifdef use_yaml
use fm_yaml_mod
#endif

implicit none
private

#include<file_version.h>
logical            :: module_is_initialized  = .false.

public :: field_manager_init   !< (nfields, [table_name]) returns number of fields
public :: field_manager_end    !< ()
public :: find_field_index     !< (model, field_name) or (list_path)
public :: find_field_index_old !< (model, field_name) returns index of field_name in
public :: find_field_index_new
public :: get_field_info       !< (n,fld_type,fld_name,model,num_methods)
                               !! Returns parameters relating to field n.
public :: get_field_method     !< (n, m, method) Returns the m-th method of field n
public :: get_field_methods    !< (n, methods) Returns the methods related to field n
public :: parse                !< (text, label, values) Overloaded function to parse integer,
                               !! real or character. Parse returns the number of values
                               !! decoded (> 1 => an array of values)
public :: fm_change_list       !< (list) return success
public :: fm_change_root       !< (list) return success
public :: fm_dump_list         !< (list [, recursive]) return success
public :: fm_exists            !< (field) return success
public :: fm_get_index         !< (field) return index
public :: fm_get_current_list  !< () return path
public :: fm_get_length        !< (list) return length
public :: fm_get_type          !< (field) return string
public :: fm_get_value         !< (entry, value [, index]) return success !! generic
public :: fm_get_value_integer !<   as above (overloaded function)
public :: fm_get_value_logical !<   as above (overloaded function)
public :: fm_get_value_real_r4 !<   as above (overloaded function)
public :: fm_get_value_real_r8 !<   as above (overloaded function)
public :: fm_get_value_string  !<   as above (overloaded function)
public :: fm_init_loop         !< (list, iter)
public :: fm_loop_over_list    !< (list, name, type, index) return success
                               !! (iter, name, type, index) return success
public :: fm_new_list          !< (list [, create] [, keep]) return index
public :: fm_new_value         !< (entry, value [, create] [, index]) return index !! generic
public :: fm_new_value_integer !<   as above (overloaded function)
public :: fm_new_value_logical !<   as above (overloaded function)
public :: fm_new_value_real_r4 !<   as above (overloaded function)
public :: fm_new_value_real_r8 !<   as above (overloaded function)
public :: fm_new_value_string  !<   as above (overloaded function)
public :: fm_reset_loop        !< ()
public :: fm_return_root       !< () return success
public :: fm_modify_name       !< (oldname, newname) return success
public :: fm_query_method      !< (name, method_name, method_control) return success and
                               !! name and control strings
public :: fm_find_methods      !< (list, methods, control) return success and name and
                               !! control strings.
public :: fm_copy_list         !< (list, suffix, [create]) return index
private :: create_field        ! (list_p, name) return field pointer
private :: dump_list           ! (list_p, recursive, depth) return success
private :: find_base           ! (field, path, base)
private :: find_field          ! (field, list_p) return field pointer
private :: find_head           ! (field, head, rest)
private :: find_list           ! (list, list_p, create) return field pointer
private :: get_field           ! (field, list_p) return field pointer
private :: initialize_module_variables          ! ()
private :: make_list           ! (list_p, name) return field pointer

!> The length of a character string representing the field name.
integer, parameter, public :: fm_field_name_len = 48
!! TODO this should be removed in favor of the global FMS_PATH_LEN
!! when possible, currently used in ocean_BGC and land_lad2
!> The length of a character string representing the field path.
integer, parameter, public :: fm_path_name_len  = FMS_PATH_LEN
!> The length of a character string representing character values for the field.
integer, parameter, public :: fm_string_len     = 1024
!> The length of a character string representing the various types that the values of the field can take.
integer, parameter, public :: fm_type_name_len  = 8
!> Number of models (ATMOS, OCEAN, LAND, ICE, COUPLER).
integer, parameter, public :: NUM_MODELS        = 5
!> The value returned if a field is not defined.
integer, parameter, public :: NO_FIELD          = -1
!> Atmospheric model.
integer, parameter, public :: MODEL_ATMOS       = 1
!> Ocean model.
integer, parameter, public :: MODEL_OCEAN       = 2
!> Land model.
integer, parameter, public :: MODEL_LAND        = 3
!> Ice model.
integer, parameter, public :: MODEL_ICE         = 4
!> Ice model.
integer, parameter, public :: MODEL_COUPLER     = 5
!> Model names, e.g. MODEL_NAMES(MODEL_OCEAN) is 'oceanic'
character(len=11), parameter, public, dimension(NUM_MODELS) :: &
   MODEL_NAMES=(/'atmospheric','oceanic    ','land       ','ice        ','coupler    '/)

!> @}

!> @brief This method_type is a way to allow a component module to alter the parameters it needs
!! for various tracers.
!!
!> In essence this is a way to modify a namelist. A namelist can supply
!! default parameters for all tracers. This  method will allow the user to modify these
!! default parameters for an individual tracer. An example could be that  the user wishes to
!! use second order advection on a tracer and also use fourth order advection on a second
!! tracer  within the same model run. The default advection could be second order and the
!! field table would then indicate  that the second tracer requires fourth order advection.
!! This would be parsed by the advection routine.
!> @ingroup field_manager_mod
type, public :: method_type

  character(len=fm_string_len) :: method_type !< This string represents a tag that a module
                                 !! using this method can key on. Typically this should
                                 !! contain some reference to the module that is calling it.
  character(len=fm_string_len) :: method_name !< This is the name of a method which the module
                                 !! can parse and use to assign different default values to
                                 !! a field method.
  character(len=fm_string_len) :: method_control !< This is the string containing parameters that
                                 !! the module can use as values  for a field method. These should
                                 !! override default values within the module.
end type

!>   This method_type is the same as method_type except that the
!!   method_control string is not present. This is used when you wish to
!!   change to a scheme within a module but do not need to pass
!!   parameters. See @ref method_type for member information.
!> @ingroup field_manager_mod
type, public :: method_type_short
  character(len=fm_string_len) :: method_type
  character(len=fm_string_len) :: method_name
end type

!>   This is the same as method_type except that the
!!   method_control and method_name strings are not present. This is used
!!   when you wish to change to a scheme within a module but do not need
!!   to pass parameters.
!> @ingroup field_manager_mod
type, public :: method_type_very_short
  character(len=fm_string_len) :: method_type
end type

!> Iterator over the field manager list
!> @ingroup field_manager_mod
type, public :: fm_list_iter_type
   type(field_def), pointer    :: ptr => NULL()  !< pointer to the current field
end type fm_list_iter_type

!> @ingroup field_manager_mod
type(method_type), public :: default_method

!> @brief Returns an index corresponding to the given field name.
!!
!> Model number can be given for old method.
!! <br>Example usage:
!! @code{.F90}
!! value=find_field_index( model, field_name )
!! value=find_field_index( field_name )
!! @endcode
!> @ingroup field_manager_mod
interface find_field_index
  module procedure  find_field_index_old
  module procedure  find_field_index_new
end interface

!> @brief A function to parse an integer or an array of integers,
!! a real or an array of reals, a string or an array of strings.
!!
!> Parse is an integer function that decodes values from a text string.
!! The text string has the form: "label=list" where "label" is an
!! arbitrary user defined label describing the values being decoded,
!! and "list" is a list of one or more values separated by commas.
!! The values may be integer, real, or character.
!! Parse returns the number of values decoded.
!! <br>Example usage:
!! @code{.F90}
!! number = parse(text, label, value)
!! @endcode
!> @ingroup field_manager_mod
interface parse
  module procedure  parse_real_r4
  module procedure  parse_real_r8
  module procedure  parse_reals_r4
  module procedure  parse_reals_r8
  module procedure  parse_integer
  module procedure  parse_integers
  module procedure  parse_string
  module procedure  parse_strings
end interface

!> @brief An overloaded function to assign a value to a field.
!!
!> Allocate and initialize a new value and return the index.
!! If an error condition occurs the parameter NO_FIELD is returned.
!!
!! If the type of the field is changing (e.g. real values being transformed to
!! integers), then any previous values for the field are removed and replaced
!! by the value passed in the present call to this function.
!!
!! If append is present and .true., then index cannot be greater than 0 if
!! it is present.
!! <br> Example usage:
!! @code{.F90}
!! field_index= fm_new_value(name, value, [create], [index], [append])
!! @endcode
!> @ingroup field_manager_mod
interface  fm_new_value
  module procedure  fm_new_value_integer
  module procedure  fm_new_value_logical
  module procedure  fm_new_value_real_r4
  module procedure  fm_new_value_real_r8
  module procedure  fm_new_value_string
end interface

!> @brief An overloaded function to find and extract a value for a named field.
!!
!> Find and extract the value for name. The value may be of type real,
!! integer, logical or character. If a single value from an array  of values
!! is required, an optional index can be supplied.
!! Return true for success and false for failure
!! <br> Example usage:
!! @code{.F90}
!! success = fm_get_value(name, value, index)
!! @endcode
!> @ingroup field_manager_mod
interface  fm_get_value
  module procedure  fm_get_value_integer
  module procedure  fm_get_value_logical
  module procedure  fm_get_value_real_r4
  module procedure  fm_get_value_real_r8
  module procedure  fm_get_value_string
end interface

!> @brief A function for looping over a list.
!!
!> Loop over the list, setting the name, type and index
!! of the next field. Return false at the end of the loop.
!! <br> Example usage:
!! @code{.F90}
!! success = fm_loop_over_list(list, name, field_type, index)
!! @endcode
!> @ingroup field_manager_mod
interface fm_loop_over_list
  module procedure  fm_loop_over_list_new
  module procedure  fm_loop_over_list_old
end interface

character(len=17), parameter :: module_name       = 'field_manager_mod'
character(len=33), parameter :: error_header      = '==>Error from '//trim(module_name)//': '
character(len=35), parameter :: warn_header       = '==>Warning from '//trim(module_name)//': '
character(len=32), parameter :: note_header       = '==>Note from '//trim(module_name)//': '
character(len=1),  parameter :: comma             = ","
character(len=1),  parameter :: list_sep          = '/'
!TODO these variable can be removed when the legacy table is no longer used
character(len=1),  parameter :: comment           = '#'
character(len=1),  parameter :: dquote            = '"'
character(len=1),  parameter :: equal             = '='
character(len=1),  parameter :: squote            = "'"
!
integer,           parameter :: null_type         = 0
integer,           parameter :: integer_type      = 1
integer,           parameter :: list_type         = 2
integer,           parameter :: logical_type      = 3
integer,           parameter :: real_type         = 4
integer,           parameter :: string_type       = 5
integer,           parameter :: num_types         = 5
integer,           parameter :: array_increment   = 10
!TODO these variable can be removed when the legacy table is no longer used
integer,           parameter :: MAX_FIELDS        = MAXFIELDS_
integer,           parameter :: MAX_FIELD_METHODS = MAXFIELDMETHODS_
!

!> @brief Private type for internal use
!> @ingroup field_manager_mod
type, private :: field_mgr_type
  character(len=fm_field_name_len)                    :: field_type
  character(len=fm_string_len)                        :: field_name
  integer                                             :: model, num_methods
  type(method_type), dimension(:), allocatable        :: methods !< methods associated with this field name
end type field_mgr_type

!TODO These two types: field_names_type and field_names_type_short
!! will no longer be needed when the legacy field table is not used
!> @brief Private type for internal use
!> @ingroup field_manager_mod
type, private :: field_names_type
  character(len=fm_field_name_len)                    :: fld_type
  character(len=fm_field_name_len)                    :: mod_name
  character(len=fm_string_len)                        :: fld_name
end  type field_names_type

!> @brief Private type for internal use
!> @ingroup field_manager_mod
type, private :: field_names_type_short
  character(len=fm_field_name_len)                    :: fld_type
  character(len=fm_field_name_len)                    :: mod_name
end type field_names_type_short

!> @brief Private type for internal use
!> @ingroup field_manager_mod
type, private :: field_def
  character (len=fm_field_name_len)                   :: name
  integer                                             :: index
  type (field_def), pointer                           :: parent => NULL()
  integer                                             :: field_type
  integer                                             :: length
  integer                                             :: array_dim
  integer                                             :: max_index
  type (field_def), pointer                           :: first_field => NULL()
  type (field_def), pointer                           :: last_field => NULL()
  integer, allocatable, dimension(:)                  :: i_value
  logical, allocatable, dimension(:)                  :: l_value
  real(r8_kind), allocatable, dimension(:)            :: r_value !< string to real conversion will be done at r8;
                                                                 !! all real values will be stored as r8_kind.
  character(len=fm_string_len), allocatable, dimension(:) :: s_value
  type (field_def), pointer                           :: next => NULL()
  type (field_def), pointer                           :: prev => NULL()
end type field_def

!> @addtogroup field_manager_mod
!> @{

type(field_mgr_type), dimension(:), allocatable, private :: fields !< fields of field_mgr_type

character(len=FMS_PATH_LEN)  :: loop_list
character(len=fm_type_name_len)  :: field_type_name(num_types)
character(len=fm_field_name_len) :: save_root_name
! The string set is the set of characters.
character(len=52)                :: set = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
! If a character in the string being parsed matches a character within
! the string set_nonexp then the string being parsed cannot be a number.
character(len=50)                :: set_nonexp = "ABCDFGHIJKLMNOPQRSTUVWXYZabcdfghijklmnopqrstuvwxyz"
! If a character in the string being parsed matches a character within
! the string setnum then the string may be a number.
character(len=13)                :: setnum     = "0123456789+-."
integer                          :: num_fields         = 0
type (field_def), pointer        :: loop_list_p        => NULL()
type (field_def), pointer        :: current_list_p     => NULL()
type (field_def), pointer        :: root_p             => NULL()
type (field_def), pointer        :: save_root_parent_p => NULL()
type (field_def), target, save   :: root

logical :: use_field_table_yaml = .false. !< .True. if using the field_table.yaml,
                                          !! .false. if using the legacy field_table

namelist /field_manager_nml/ use_field_table_yaml

contains

!> @brief Routine to initialize the field manager.
!!
!> This routine reads from a file containing yaml paramaters.
!! These yaml parameters contain information on which schemes are
!! needed within various modules. The field manager does not
!! initialize any of those schemes however. It simply holds the
!! information and is queried by the appropriate  module.
!!
!! The routine has two loops. The first loop initializes the my_table object
!! and counts the number of fields contained therein. The second loop is the
!! main loop that acts on each field in the my_table object, defining a list
!! object (in the field_manager definition) from which various fm routines may be
!! called, as well as populating the "fields" object and the "methods" objects
!! within each field object. The "fields" and "methods" objects are then used
!! with the subroutine new_name to append various characteristics to the list
!! object. Note that the "fields" and "methods" objects are also used with other
!! fm routines in a bit of a parallel system.
subroutine field_manager_init(nfields, table_name)
integer,                      intent(out), optional :: nfields    !< number of fields
character(len=fm_string_len), intent(in),  optional :: table_name !< Name of the field table, default

if (module_is_initialized) then
   if(present(nfields)) nfields = num_fields
   return
endif

call initialize_module_variables()

!TODO the use_field_table_yaml namelist can be removed when the legacy table is no longer in used
if (use_field_table_yaml) then
  !Crash if you are not compiling with -Duse_yaml or if the field_table is present
#ifndef use_yaml
  call mpp_error(FATAL, "You cannot have use_field_table_yaml=.true. without compiling with -Duse_yaml")
#else
  if (file_exists("field_table")) &
    call mpp_error(FATAL, "You cannot have the legacy field_table if use_field_table_yaml=.true.")

  call mpp_error(NOTE, "You are using the yaml version of the field_table")
  call read_field_table_yaml(nfields, table_name)
#endif
else
  if (file_exists("field_table.yaml")) &
    call mpp_error(FATAL, "You cannot have the yaml field_table if use_field_table_yaml=.false.")
  call mpp_error(NOTE, "You are using the legacy version of the field_table")
  call read_field_table_legacy(nfields, table_name)
endif

end subroutine field_manager_init

#ifdef use_yaml

!> @brief Routine to read and parse the field table yaml
subroutine read_field_table_yaml(nfields, table_name)
integer,                      intent(out), optional :: nfields    !< number of fields
character(len=*),  intent(in),  optional :: table_name !< Name of the field table file, default is 'field_table.yaml'

character(len=FMS_FILE_LEN)     :: tbl_name !< field_table yaml file
character(len=fm_string_len)    :: method_control !< field_table yaml file
integer                         :: h, i, j, k, l, m !< dummy integer buffer
type (fmTable_t)                :: my_table !< the field table
integer                         :: model !< model assocaited with the current field
character(len=FMS_PATH_LEN)     :: list_name !< field_manager list name
character(len=fm_string_len)    :: subparamvalue !< subparam value to be used when defining new name
character(len=fm_string_len)    :: fm_yaml_null !< useful hack when OG subparam does not contain an equals sign
integer                         :: current_field !< field index within loop
integer                         :: index_list_name !< integer used as check for "no field"
integer                         :: subparamindex !< index to identify whether subparams exist for this field
logical                         :: fm_success !< logical for whether fm_change_list was a success
logical                         :: subparams !< logical whether subparams exist in this iteration

character(len=FMS_FILE_LEN) :: filename !< Name of the expected field_table.yaml

if (.not.PRESENT(table_name)) then
   tbl_name = 'field_table.yaml'
else
   tbl_name = trim(table_name)
endif

call get_instance_filename(tbl_name, filename)
if (index(trim(filename), "ens_") .ne. 0) then
  if (file_exists(filename) .and. file_exists(tbl_name)) &
    call mpp_error(FATAL, "Both "//trim(tbl_name)//" and "//trim(filename)//" exists, pick one!")

  !< If the end_* file does not exist, revert back to tbl_name
  !! where every ensemble is using the same yaml
  if (.not. file_exists(filename)) filename = tbl_name
endif

if (.not. file_exists(trim(filename))) then
  if(present(nfields)) nfields = 0
  return
endif

! Construct my_table object
call build_fmTable(my_table, trim(filename))

do h=1,size(my_table%types)
  do i=1,size(my_table%types(h)%models)
    do j=1,size(my_table%types(h)%models(i)%variables)
      num_fields = num_fields + 1
    end do
  end do
end do

allocate(fields(num_fields))

current_field = 0
do h=1,size(my_table%types)
  do i=1,size(my_table%types(h)%models)
    select case (my_table%types(h)%models(i)%name)
    case ('coupler_mod')
       model = MODEL_COUPLER
    case ('atmos_mod')
       model = MODEL_ATMOS
    case ('ocean_mod')
       model = MODEL_OCEAN
    case ('land_mod')
       model = MODEL_LAND
    case ('ice_mod')
       model = MODEL_ICE
    case default
      call mpp_error(FATAL, trim(error_header)//'The model name is unrecognised : &
        &'//trim(my_table%types(h)%models(i)%name))
    end select
    do j=1,size(my_table%types(h)%models(i)%variables)
      current_field = current_field + 1
      list_name = list_sep//lowercase(trim(my_table%types(h)%models(i)%name))//list_sep//&
               lowercase(trim(my_table%types(h)%name))//list_sep//&
               lowercase(trim(my_table%types(h)%models(i)%variables(j)%name))
      index_list_name = fm_new_list(list_name, create = .true.)
      if ( index_list_name == NO_FIELD ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set field list for '//trim(list_name))
      fm_success = fm_change_list(list_name)
      fields(current_field)%model       = model
      fields(current_field)%field_name  = lowercase(trim(my_table%types(h)%models(i)%variables(j)%name))
      fields(current_field)%field_type  = lowercase(trim(my_table%types(h)%name))
      fields(current_field)%num_methods = size(my_table%types(h)%models(i)%variables(j)%keys)
      allocate(fields(current_field)%methods(fields(current_field)%num_methods))
      if(fields(current_field)%num_methods.gt.0) then
        subparams = (size(my_table%types(h)%models(i)%variables(j)%attributes) .gt. 0)
        do k=1,size(my_table%types(h)%models(i)%variables(j)%keys)
          fields(current_field)%methods(k)%method_type = &
            lowercase(trim(my_table%types(h)%models(i)%variables(j)%keys(k)))
          fields(current_field)%methods(k)%method_name = &
            lowercase(trim(my_table%types(h)%models(i)%variables(j)%values(k)))
          if (.not.subparams) then
            call new_name(list_name, my_table%types(h)%models(i)%variables(j)%keys(k),&
              my_table%types(h)%models(i)%variables(j)%values(k) )
          else
            subparamindex=-1
            do l=1,size(my_table%types(h)%models(i)%variables(j)%attributes)
              if(lowercase(trim(my_table%types(h)%models(i)%variables(j)%attributes(l)%paramname)).eq.&
                lowercase(trim(fields(current_field)%methods(k)%method_type))) then
                  subparamindex = l
                  exit
              end if
            end do
            if (subparamindex.eq.-1) then
              call new_name(list_name, my_table%types(h)%models(i)%variables(j)%keys(k),&
                my_table%types(h)%models(i)%variables(j)%values(k) )
            else
              do m=1,size(my_table%types(h)%models(i)%variables(j)%attributes(subparamindex)%keys)
                method_control = " "
                subparamvalue = " "
                if (trim(my_table%types(h)%models(i)%variables(j)%values(k)).eq.'fm_yaml_null') then
                  fm_yaml_null = ''
                else
                  fm_yaml_null = trim(my_table%types(h)%models(i)%variables(j)%values(k))//'/'
                end if
                method_control = trim(my_table%types(h)%models(i)%variables(j)%keys(k))//"/"//&
                  &trim(fm_yaml_null)//&
                  &trim(my_table%types(h)%models(i)%variables(j)%attributes(subparamindex)%keys(m))
                subparamvalue = trim(my_table%types(h)%models(i)%variables(j)%attributes(subparamindex)%values(m))
                call new_name(list_name, method_control, subparamvalue)
              end do
            end if
          end if
        end do
      end if
    end do
  end do
end do

if (present(nfields)) nfields = num_fields
end subroutine read_field_table_yaml

!> @brief Subroutine to add new values to list parameters.
!!
!> This subroutine uses input strings list_name, method_name
!! and val_name_in to add new values to the list. Given
!! list_name a new list item is created that is named
!! method_name and is given the value or values in
!! val_name_in. If there is more than 1 value in
!! val_name_in, these values should be  comma-separated.
subroutine new_name_yaml ( list_name, method_name_in , val_name_in)
character(len=*), intent(in)    :: list_name !< The name of the field that is of interest here.
character(len=*), intent(in)    :: method_name_in !< The name of the method that values are
                                                  !! being supplied for.
character(len=*), intent(inout) :: val_name_in !< The value or values that will be parsed and
                                               !! used as the value when creating a new field or fields.

character(len=fm_string_len)       :: method_name !< name of method to be attached to new list
character(len=fm_string_len)       :: val_name !< value name (to be converted to appropriate type)
integer, dimension(:), allocatable :: end_val !< end values in comma separated list
integer, dimension(:), allocatable :: start_val !< start values in comma separated list
integer                            :: i !< loop index
integer                            :: index_t !< appending index
integer                            :: num_elem !< number of elements in comma list
integer                            :: val_int !< value when converted to integer
integer                            :: val_type !< value type represented as integer for use in select case
logical                            :: append_new !< whether or not to append to existing list structure
logical                            :: val_logic !< value when converted to logical
real(r8_kind)                      :: val_real !< value when converted to real.
                                               !! All strings will be converted to r8_kind reals.

call strip_front_blanks(val_name_in)
method_name = trim(method_name_in)
call strip_front_blanks(method_name)

index_t  = 1
num_elem = 1
append_new = .false.

! If the array of values being passed in is a comma delimited list then count
! the number of elements.

do i = 1, len_trim(val_name_in)
  if ( val_name_in(i:i) == comma ) then
    num_elem = num_elem + 1
  endif
enddo

allocate(start_val(num_elem))
allocate(end_val(num_elem))
start_val(1) = 1
end_val(:) = len_trim(val_name_in)

num_elem = 1
do i = 1, len_trim(val_name_in)
  if ( val_name_in(i:i) == comma ) then
    end_val(num_elem) = i-1
    start_val(num_elem+1) = i+1
    num_elem = num_elem + 1
  endif
enddo

do i = 1, num_elem

  if ( i .gt. 1 .or. index_t .eq. 0 ) then
    append_new = .true.
    index_t = 0 ! If append is true then index must be <= 0
  endif
  val_type = string_type  ! Assume it is a string
  val_name = val_name_in(start_val(i):end_val(i))
  call strip_front_blanks(val_name)

  if ( scan(val_name(1:1), setnum ) > 0 ) then
    if ( scan(val_name, set_nonexp ) .le. 0 ) then
      if ( scan(val_name, '.') > 0 .or. scan(val_name, 'e') > 0 .or. scan(val_name, 'E') > 0) then
        read(val_name, *) val_real
        val_type = real_type
      else
        read(val_name, *) val_int
        val_type = integer_type
      endif
    endif
  endif

  if ( len_trim(val_name) == 1 .or. len_trim(val_name) == 3) then
    if ( val_name == 't' .or. val_name == 'T' .or. val_name == '.t.' .or. val_name == '.T.' ) then
      val_logic = .TRUE.
      val_type = logical_type
    endif
    if ( val_name == 'f' .or. val_name == 'F' .or. val_name == '.f.' .or. val_name == '.F.' ) then
      val_logic = .FALSE.
      val_type = logical_type
    endif
  endif
  if ( trim(lowercase(val_name)) == 'true' .or. trim(lowercase(val_name)) == '.true.' ) then
    val_logic = .TRUE.
    val_type = logical_type
  endif
  if ( trim(lowercase(val_name)) == 'false' .or. trim(lowercase(val_name)) == '.false.' ) then
    val_logic = .FALSE.
    val_type = logical_type
  endif

  select case(val_type)

    case (integer_type)
      if ( fm_new_value( method_name, val_int, create = .true., index = index_t, append = append_new ) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (I) for '//trim(list_name))

    case (logical_type)
      if ( fm_new_value( method_name, val_logic, create = .true., index = index_t, append = append_new) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (L) for '//trim(list_name))

    case (real_type)
      if ( fm_new_value( method_name, val_real, create = .true., index = index_t, append = append_new) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (R) for '//trim(list_name))

    case (string_type)
      if ( fm_new_value( method_name, val_name, create = .true., index = index_t, append = append_new) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (S) for '//trim(list_name))
    case default
      call mpp_error(FATAL, trim(error_header)//'Could not find a valid type to set the '//trim(method_name)//&
                            ' for '//trim(list_name))

  end select

enddo
  deallocate(start_val)
  deallocate(end_val)

end subroutine new_name_yaml
#endif

!> @brief Routine to read and parse the field table yaml
!!
!> This routine reads from a file containing formatted strings.
!! These formatted strings contain information on which schemes are
!! needed within various modules. The field manager does not
!! initialize any of those schemes however. It simply holds the
!! information and is queried by the appropriate  module.
subroutine read_field_table_legacy(nfields, table_name)

integer,                      intent(out), optional :: nfields !< number of fields
character(len=fm_string_len), intent(in), optional :: table_name !< Name of the field table, default
                                                                 !! is 'field_table'

character(len=1024)              :: record
character(len=fm_string_len)     :: control_str
character(len=FMS_PATH_LEN)  :: list_name
character(len=fm_string_len)     :: method_name
character(len=fm_string_len)     :: name_str
character(len=fm_string_len)     :: type_str
character(len=fm_string_len)     :: val_name
character(len=fm_string_len)     :: tbl_name
integer                          :: control_array(MAX_FIELDS,3)
integer                          :: endcont
integer                          :: icount
integer                          :: index_list_name
integer                          :: iunit
integer                          :: l
integer                          :: log_unit
integer                          :: ltrec
integer                          :: m
integer                          :: midcont
integer                          :: model
integer                          :: startcont
integer                          :: io_status
logical                          :: flag_method
logical                          :: fm_success
type(field_names_type_short)     :: text_names_short
type(field_names_type)           :: text_names
type(method_type_short)          :: text_method_short
type(method_type)                :: text_method
type(method_type_very_short)     :: text_method_very_short

if (.not.PRESENT(table_name)) then
   tbl_name = 'field_table'
else
   tbl_name = trim(table_name)
endif
if (.not. file_exists(trim(tbl_name))) then
  if(present(nfields)) nfields = 0
  return
endif

allocate(fields(MAX_FIELDS))

open(newunit=iunit, file=trim(tbl_name), action='READ', iostat=io_status)
if(io_status/=0) call mpp_error(FATAL, 'field_manager_mod: Error in opening file '//trim(tbl_name))
!write_version_number should precede all writes to stdlog from field_manager
call write_version_number("FIELD_MANAGER_MOD", version)
log_unit = stdlog()
do while (.TRUE.)
   read(iunit,'(a)',end=89,err=99) record
   write( log_unit,'(a)' )record
   if (record(1:1) == "#" ) cycle
   ltrec =  LEN_TRIM(record)
   if (ltrec .le. 0 ) cycle ! Blank line


         icount = 0
         do l= 1, ltrec
            if (record(l:l) == '"' ) then
               icount = icount + 1
            endif
         enddo
      if (icount > 6 ) then
        call mpp_error(FATAL,trim(error_header)//'Too many fields in field table header entry.'//trim(record))
      endif

         select case (icount)
           case (6)
             read(record,*,end=79,err=79) text_names
             text_names%fld_type = lowercase(trim(text_names%fld_type))
             text_names%mod_name = lowercase(trim(text_names%mod_name))
             text_names%fld_name = lowercase(trim(text_names%fld_name))
           case(4)
! If there is no control string then the last string can be omitted and there are only 4 '"' in the record.
             read(record,*,end=79,err=79) text_names_short
             text_names%fld_type = lowercase(trim(text_names_short%fld_type))
             text_names%mod_name = lowercase(trim(text_names_short%mod_name))
             text_names%fld_name = lowercase(trim(text_names_short%mod_name))
           case(2)
! If there is only the method_type string then the last 2 strings need to be blank and there
! are only 2 '"' in the record.
             read(record,*,end=79,err=79) text_names_short
             text_names%fld_type = lowercase(trim(text_names_short%fld_type))
             text_names%mod_name = lowercase(trim(text_names_short%mod_name))
             text_names%fld_name = lowercase(trim(text_names_short%mod_name))
           case default
!       There is an unterminated or unquoted string in the field table entry.
             text_names%fld_type = " "
             text_names%mod_name = lowercase(trim(record))
             text_names%fld_name = " "
         end select

! Create a list with Rick Slaters field manager code

   list_name = list_sep//trim(text_names%mod_name)//list_sep//trim(text_names%fld_type)//&
               list_sep//trim(text_names%fld_name)

   index_list_name = fm_new_list(list_name, create = .true.)
   if ( index_list_name == NO_FIELD ) &
     call mpp_error(FATAL, trim(error_header)//'Could not set field list for '//trim(list_name))

   fm_success = fm_change_list(list_name)
   select case (text_names%mod_name)
   case ('coupler_mod')
      model = MODEL_COUPLER
   case ('atmos_mod')
      model = MODEL_ATMOS
   case ('ocean_mod')
      model = MODEL_OCEAN
   case ('land_mod')
      model = MODEL_LAND
   case ('ice_mod')
      model = MODEL_ICE
   case default
     call mpp_error(FATAL, trim(error_header)//'The model name is unrecognised : '//trim(text_names%mod_name))
   end select
   if (find_field_index(list_name) > 0) then
      num_fields = num_fields + 1

      if (num_fields > MAX_FIELDS) call mpp_error(FATAL,trim(error_header)//'max fields exceeded')
      fields(num_fields)%model       = model
      fields(num_fields)%field_name  = lowercase(trim(text_names%fld_name))
      fields(num_fields)%field_type  = lowercase(trim(text_names%fld_type))
      fields(num_fields)%num_methods = 0
      allocate(fields(num_fields)%methods(MAX_FIELD_METHODS))
      call check_for_name_duplication

! Check to see that the first line is not the only line
      if ( record(LEN_TRIM(record):LEN_TRIM(record)) == list_sep) cycle

      flag_method = .TRUE.
      m = 1
      do while (flag_method)
         read(iunit,'(a)',end=99,err=99) record
! If the line is blank then fetch the next line.
         if (LEN_TRIM(record) .le. 0) cycle
! If the last character in the line is / then this is the end of the field methods
         if ( record(LEN_TRIM(record):LEN_TRIM(record)) == list_sep) then
            flag_method = .FALSE.
            if (LEN_TRIM(record) == 1) cycle
            record = record(:LEN_TRIM(record)-1) ! Remove the end of field method marker
         endif
! If the line is now blank, after removing the field separator marker, then fetch the next line.
         if (LEN_TRIM(record) .le. 0) cycle
! If the first character in the line is # then it is treated as a comment
         if (record(1:1) == comment ) cycle

         icount = 0
         do l= 1, LEN_TRIM(record)
            if (record(l:l) == dquote ) then
               icount = icount + 1
            endif
         enddo
      if (icount > 6 ) call mpp_error(FATAL,trim(error_header)//'Too many fields in field entry.'//trim(record))

      if (.not. fm_change_list ( list_name)) &
         call mpp_error(FATAL, trim(error_header)//'Could not change to '//trim(list_name)//' list')

      select case (icount)
        case (6)
          read(record,*,end=99,err=99) text_method
          fields(num_fields)%methods(m)%method_type = lowercase(trim(text_method%method_type))
          fields(num_fields)%methods(m)%method_name = lowercase(trim(text_method%method_name))
          fields(num_fields)%methods(m)%method_control = lowercase(trim(text_method%method_control))

          type_str    = text_method%method_type
          name_str    = text_method%method_name
          control_str = text_method%method_control

        case(4)
! If there is no control string then the last string can be omitted and there are only 4 '"' in the record.
          read(record,*,end=99,err=99) text_method_short
          fields(num_fields)%methods(m)%method_type =&
               & lowercase(trim(text_method_short%method_type))
          fields(num_fields)%methods(m)%method_name =&
               & lowercase(trim(text_method_short%method_name))
          fields(num_fields)%methods(m)%method_control = " "

          type_str    = text_method_short%method_type
          name_str    = ""
          control_str = text_method_short%method_name

        case(2)
! If there is only the method_type string then the last 2 strings need to be blank and there
! are only 2 '"' in the record.
          read(record,*,end=99,err=99) text_method_very_short
          fields(num_fields)%methods(m)%method_type = lowercase(trim(text_method_very_short%method_type))
          fields(num_fields)%methods(m)%method_name = " "
          fields(num_fields)%methods(m)%method_control = " "

          type_str    = ""
          name_str    = ""
          control_str = text_method_very_short%method_type

        case(0)
          read(record,'(A)',end=99,err=99) control_str
          type_str = ""
          name_str = ""

        case default
          call mpp_error(FATAL,trim(error_header)//'Unterminated field in field entry.'//trim(record))
      end select

! This section of code breaks the control string into separate strings.
! The array control_array contains the following parameters.
! control_array(:,1) = index within control_str of the first character of the name.
! control_array(:,2) = index within control_str of the equal sign
! control_array(:,3) = index within control_str of the last character of the value.
!
! control_array(:,1)   -> control_array(:,2) -1 = name of the parameter.
! control_array(:,2)+1 -> control_array(:,3)    = value of the parameter.

      ltrec= len_trim(control_str)
      control_array(:,1) = 1
      control_array(:,2:3) = ltrec
      icount = 0
      do l= 1, ltrec
         if (control_str(l:l) == equal ) then
            icount = icount + 1
            control_array(icount,2) = l ! Middle of string
         elseif (control_str(l:l) == comma ) then
            if (icount .eq. 0) then
              call mpp_error(FATAL,trim(error_header) //                                &
                   ' Bad format for field entry (comma without equals sign): ''' //     &
                   trim(control_str) // '''')
            elseif (icount .gt. MAX_FIELDS) then
              call mpp_error(FATAL,trim(error_header) //        &
                   ' Too many fields in field entry: ''' //     &
                   trim(control_str) // '''')
            else
              control_array(icount,3) = l-1   !End of previous string
              control_array(min(MAX_FIELDS,icount+1),1) = l+1 !Start of next string
            endif
         endif
      enddo

      ! Make sure that we point to the end of the string (minus any trailing comma)
      ! for the last set of values. This fixes the case where the last set of values
      ! is a comma separated list

      if (control_str(ltrec:ltrec) .ne. comma) then
        control_array(max(1,icount),3) = ltrec
      endif

      if ( icount == 0 ) then
        method_name = type_str
        if (len_trim(method_name) > 0 ) then
          method_name = trim(method_name)//list_sep// trim(name_str)
        else
          method_name = trim(name_str)
        endif
        val_name = control_str

        call new_name(list_name, method_name, val_name )

      else

        do l = 1,icount
          startcont = control_array(l,1)
          midcont   = control_array(l,2)
          endcont   = control_array(l,3)

          method_name = trim(type_str)
          if (len_trim(method_name) > 0 ) then
            method_name = trim(method_name)//list_sep// trim(name_str)
          else
            method_name = trim(name_str)
          endif

          if (len_trim(method_name) > 0 ) then
            method_name = trim(method_name)//list_sep//&
                          trim(control_str(startcont:midcont-1))
          else
            method_name = trim(control_str(startcont:midcont-1))
          endif
          val_name =    trim(control_str(midcont+1:endcont))

          call new_name(list_name, method_name, val_name )
        enddo

      endif

      fields(num_fields)%num_methods = fields(num_fields)%num_methods + 1
      if (fields(num_fields)%num_methods > MAX_FIELD_METHODS) &
         call mpp_error(FATAL,trim(error_header)//'Maximum number of methods for field exceeded')
         m = m + 1
      enddo
   else
      flag_method = .TRUE.
      do while (flag_method)
         read(iunit,'(A)',end=99,err=99) record
         if ( record(LEN_TRIM(record):LEN_TRIM(record)) == list_sep) then
            flag_method = .FALSE.
         endif
      enddo
   endif
79 continue
enddo

89 continue
close(iunit, iostat=io_status)
if(io_status/=0) call mpp_error(FATAL, 'field_manager_mod: Error in closing file '//trim(tbl_name))


if(present(nfields)) nfields = num_fields

default_method%method_type = 'none'
default_method%method_name = 'none'
default_method%method_control = 'none'
return

99 continue

call mpp_error(FATAL,trim(error_header)//' Error reading field table. Record = '//trim(record))

end subroutine read_field_table_legacy

subroutine check_for_name_duplication
integer :: i

! Check that name is unique amoung fields of the same field_type and model.
do i=1,num_fields-1
  if ( fields(i)%field_type == fields(num_fields)%field_type .and. &
       fields(i)%model      == fields(num_fields)%model      .and. &
       fields(i)%field_name == fields(num_fields)%field_name ) then
    if (mpp_pe() .eq. mpp_root_pe()) then
      call mpp_error(WARNING,'Error in field_manager_mod. Duplicate field name: Field type='//&
         trim(fields(i)%field_type)// &
         ',  Model='//trim(MODEL_NAMES(fields(i)%model))// &
         ',  Duplicated name='//trim(fields(i)%field_name))
    endif
  endif
enddo

end subroutine check_for_name_duplication

!> @brief Subroutine to add new values to list parameters.
!!
!> This subroutine uses input strings list_name, method_name
!! and val_name_in to add new values to the list. Given
!! list_name a new list item is created that is named
!! method_name and is given the value or values in
!! val_name_in. If there is more than 1 value in
!! val_name_in, these values should be  comma-separated.
subroutine new_name ( list_name, method_name_in , val_name_in)
character(len=*), intent(in)    :: list_name !< The name of the field that is of interest here.
character(len=*), intent(in)    :: method_name_in !< The name of the method that values are
                                                  !! being supplied for.
character(len=*), intent(inout) :: val_name_in !< The value or values that will be parsed and
                                               !! used as the value when creating a new field or fields.

character(len=fm_string_len)   :: method_name
character(len=fm_string_len)   :: val_name
integer, dimension(MAX_FIELDS) :: end_val
integer, dimension(MAX_FIELDS) :: start_val
integer                        :: i
integer                        :: index_t
integer                        :: left_br
integer                        :: num_elem
integer                        :: out_unit
integer                        :: right_br
integer                        :: val_int
integer                        :: val_type
logical                        :: append_new
logical                        :: val_logic
real(r8_kind)                  :: val_real !< all reals converted from string will be in r8_kind precision
integer                        :: length

call strip_front_blanks(val_name_in)
method_name = trim (method_name_in)
call strip_front_blanks(method_name)

index_t  = 1
num_elem = 1
append_new = .false.
start_val(1) = 1
end_val(:) = len_trim(val_name_in)

! If the array of values being passed in is a comma delimited list then count
! the number of elements.

do i = 1, len_trim(val_name_in)
  if ( val_name_in(i:i) == comma ) then
    end_val(num_elem) = i-1
    start_val(num_elem+1) = i+1
    num_elem = num_elem + 1
  endif
enddo

! Check to see if this is an array element of form array[x] = value
left_br  = scan(method_name,'[')
right_br = scan(method_name,']')
if ( num_elem .eq. 1 ) then
  if ( left_br > 0 .and. right_br == 0 ) &
    call mpp_error(FATAL, trim(error_header)//"Left bracket present without right bracket in "//trim(method_name))
  if ( left_br== 0 .and. right_br > 0 ) &
    call mpp_error(FATAL, trim(error_header)//"Right bracket present without left bracket in "//trim(method_name))
  if ( left_br > 0 .and. right_br > 0 ) then
    if ( scan( method_name(left_br+1:right_br -1), set ) > 0 ) &
       call mpp_error(FATAL, trim(error_header)//"Using a non-numeric value for index in "//trim(method_name))
    read(method_name(left_br+1:right_br -1), *) index_t
    method_name = method_name(:left_br -1)
  endif
else
! If there are multiple values then there cannot be a bracket in method_name.
  if ( left_br > 0 .or. right_br > 0 ) &
    call mpp_error(FATAL, &
      trim(error_header)//"Using a comma delimited list with an indexed array element in "//trim(method_name))
endif

do i = 1, num_elem

  if ( i .gt. 1 .or. index_t .eq. 0 ) then
    append_new = .true.
    index_t = 0 ! If append is true then index must be <= 0
  endif
  val_type = string_type  ! Assume it is a string
  val_name = val_name_in(start_val(i):end_val(i))
  call strip_front_blanks(val_name)

!
!       if the string starts and ends with matching single quotes, then this is a string
!       if there are quotes which do not match, then this is an error
!

  length = len_trim(val_name)
  if (val_name(1:1) .eq. squote) then

    if (val_name(length:length) .eq. squote) then
      val_name = val_name(2:length-1)//repeat(" ",len(val_name)-length+2)
      val_type = string_type
    elseif (val_name(length:length) .eq. dquote) then
      call mpp_error(FATAL, trim(error_header) // ' Quotes do not match in ' // trim(val_name) //       &
           ' for ' // trim(method_name) // ' of ' // trim(list_name))
    else
      call mpp_error(FATAL, trim(error_header) // ' No trailing quote in ' // trim(val_name) //         &
           ' for ' // trim(method_name) // ' of ' // trim(list_name))
    endif

  elseif (val_name(1:1) .eq. dquote .or. val_name(length:length) .eq. dquote) then

    call mpp_error(FATAL, trim(error_header) // ' Double quotes not allowed in ' // trim(val_name) //   &
         ' for ' // trim(method_name) // ' of ' // trim(list_name))

  elseif (val_name(length:length) .eq. squote) then

    call mpp_error(FATAL, trim(error_header) // ' No leading quote in ' // trim(val_name) //            &
         ' for ' // trim(method_name) // ' of ' // trim(list_name))

  else
! If the string to be parsed is a real then all the characters must be numeric,
! be a plus/minus, be a decimal point or, for exponentials, be e or E.

! If a string is an integer, then all the characters must be numeric.

  if ( scan(val_name(1:1), setnum ) > 0 ) then

! If there is a letter in the name it may only be e or E

      if ( scan(val_name, set_nonexp ) .le. 0 ) then
! It is real if there is a . in the name or the value appears exponential
        if ( scan(val_name, '.') > 0 .or. scan(val_name, 'e') > 0 .or. scan(val_name, 'E') > 0) then
          read(val_name, *) val_real
          val_type = real_type
        else
          read(val_name, *) val_int
          val_type = integer_type
        endif
      endif

    endif

! If val_name is t/T or f/F then this is a logical flag.
    if ( len_trim(val_name) == 1 .or. len_trim(val_name) == 3) then
       if ( val_name == 't' .or. val_name == 'T' .or. val_name == '.t.' .or. val_name == '.T.' ) then
         val_logic = .TRUE.
         val_type = logical_type
       endif
       if ( val_name == 'f' .or. val_name == 'F' .or. val_name == '.f.' .or. val_name == '.F.' ) then
         val_logic = .FALSE.
         val_type = logical_type
       endif
    endif
    if ( trim(lowercase(val_name)) == 'true' .or. trim(lowercase(val_name)) == '.true.' ) then
      val_logic = .TRUE.
      val_type = logical_type
    endif
    if ( trim(lowercase(val_name)) == 'false' .or. trim(lowercase(val_name)) == '.false.' ) then
      val_logic = .FALSE.
      val_type = logical_type
    endif
  endif

  select case(val_type)

    case (integer_type)
      if ( fm_new_value( method_name, val_int, create = .true., index = index_t, append = append_new ) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (I) for '//trim(list_name))

    case (logical_type)
      if ( fm_new_value( method_name, val_logic, create = .true., index = index_t, append = append_new) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (L) for '//trim(list_name))

    case (real_type)
      if ( fm_new_value( method_name, val_real, create = .true., index = index_t, append = append_new) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (R) for '//trim(list_name))

    case (string_type)
      if ( fm_new_value( method_name, val_name, create = .true., index = index_t, append = append_new) < 0 ) &
        call mpp_error(FATAL, trim(error_header)//'Could not set "' // trim(val_name) // '" for '//trim(method_name)//&
                              ' (S) for '//trim(list_name))
    case default
      call mpp_error(FATAL, trim(error_header)//'Could not find a valid type to set the '//trim(method_name)//&
                            ' for '//trim(list_name))

  end select

enddo

end subroutine new_name

!> @brief Destructor for field manager.
!!
!> This subroutine deallocates allocated variables (if allocated) and
!! changes the initialized flag to false.
subroutine field_manager_end
integer :: j

module_is_initialized = .false.

do j=1,size(fields)
  if(allocated(fields(j)%methods)) deallocate(fields(j)%methods)
end do
if(allocated(fields)) deallocate(fields)

end subroutine field_manager_end

!> @brief A routine to strip whitespace from the start of character strings.
!!
!> This subroutine removes spaces and tabs from the start of a character string.
subroutine strip_front_blanks(name)

character(len=*), intent(inout) :: name !< name to remove whitespace from

name = trim(adjustl(name))
end subroutine strip_front_blanks

!> @brief Function to return the index of the field
!!
!> This function when passed a model number and a field name will
!! return the index of the field within the field manager. This index
!! can be used to access other information from the field manager.
!! @returns The index of the field corresponding to field_name.
function find_field_index_old(model, field_name)

integer                      :: find_field_index_old
integer,          intent(in) :: model !< The number indicating which model is used.
character(len=*), intent(in) :: field_name !< The name of the field that an index is being requested for.

integer :: i

find_field_index_old = NO_FIELD

do i=1,num_fields
   if (fields(i)%model == model .and. fields(i)%field_name == lowercase(field_name)) then
      find_field_index_old = i
      return
   endif
enddo

end function find_field_index_old

!> @returns index of the field corresponding to field_name
function find_field_index_new(field_name)

integer                      :: find_field_index_new
character(len=*), intent(in) :: field_name !< The path to the name of the field that an index is
                             !! being requested for.

find_field_index_new = NO_FIELD

find_field_index_new = fm_get_index(field_name)

end function find_field_index_new

!> @brief This routine allows access to field information given an index.
!!
!> When passed an index, this routine will return the type of field,
!! the name of the field, the model which the field is associated and
!! the number of methods associated with the field.
!! <br>Example usage:
!! @code{.F90}
!! call get_field_info( n,fld_type,fld_name,model,num_methods )
!! @endcode
subroutine get_field_info(n,fld_type,fld_name,model,num_methods)
integer,          intent(in)  :: n !< index of field
character (len=*),intent(out) :: fld_type !< field type
character (len=*),intent(out) :: fld_name !< name of the field
integer, intent(out) :: model !< number indicating which model is used
integer, intent(out) :: num_methods !< number of methods

if (n < 1 .or. n > num_fields) call mpp_error(FATAL,trim(error_header)//'Invalid field index')

fld_type    = fields(n)%field_type
fld_name    = fields(n)%field_name
model       = fields(n)%model
num_methods = fields(n)%num_methods

end subroutine get_field_info

!> @brief A routine to get a specified method
!!
!> This routine, when passed a field index and a method index will
!! return the method text associated with the field(n) method(m).
subroutine get_field_method(n,m,method)

integer,           intent(in)    :: n !< index of field
integer,           intent(in)    :: m !< index of method
type(method_type) ,intent(inout) :: method !< the m-th method of field with index n

if (n < 1 .or. n > num_fields) call mpp_error(FATAL,trim(error_header)//'Invalid field index')
if (m < 1 .or. m > fields(n)%num_methods) call mpp_error(FATAL,trim(error_header)//'Invalid method index')

  method = fields(n)%methods(m)

end subroutine get_field_method

!> @brief A routine to obtain all the methods associated with a field.
!!
!> When passed a field index, this routine will return the text
!! associated with all the methods attached to the field.
subroutine get_field_methods(n,methods)

integer,          intent(in)  :: n !< field index
type(method_type),intent(inout) :: methods(:) !< an array of methods for field with index n

  if (n < 1 .or. n > num_fields) &
    call mpp_error(FATAL,trim(error_header)//'Invalid field index')

  if (size(methods(:)) <  fields(n)%num_methods) &
    call mpp_error(FATAL,trim(error_header)//'Method array too small')

  methods = default_method
  methods(1:fields(n)%num_methods) = fields(n)%methods(1:fields(n)%num_methods)

end subroutine get_field_methods

!> @returns The number of values that have been decoded. This allows
!! a user to define a large array and fill it partially with
!! values from a list. This should be the size of the value array.
function parse_integers ( text, label, values ) result (parse)
character(len=*), intent(in)  :: text !< The text string from which the values will be parsed.
character(len=*), intent(in)  :: label !< A label which describes the values being decoded.
integer,          intent(out) :: values(:) !< The value or values that have been decoded.

include 'parse.inc'
end function parse_integers

function parse_strings ( text, label, values ) result (parse)
character(len=*), intent(in)  :: text !< The text string from which the values will be parsed.
character(len=*), intent(in)  :: label !< A label which describes the values being decoded.
character(len=*), intent(out) :: values(:) !< The value or values that have been decoded.

include 'parse.inc'
end function parse_strings

function parse_integer ( text, label, parse_ival ) result (parse)
character(len=*), intent(in)  :: text !< The text string from which the values will be parsed.
character(len=*), intent(in)  :: label !< A label which describes the values being decoded.
integer,          intent(out) :: parse_ival !< The value or values that have been decoded.
integer :: parse

integer :: values(1)

   parse = parse_integers ( text, label, values )
   if (parse > 0) parse_ival = values(1)
end function parse_integer

function parse_string ( text, label, parse_sval ) result (parse)
character(len=*), intent(in)  :: text !< The text string from which the values will be parsed.
character(len=*), intent(in)  :: label !< A label which describes the values being decoded.
character(len=*), intent(out) :: parse_sval !< The value or values that have been decoded.
integer :: parse

character(len=len(parse_sval)) :: values(1)

   parse = parse_strings ( text, label, values )
   if (parse > 0) parse_sval = values(1)
end function parse_string

!> @brief A function to create a field as a child of parent_p. This will return
!! a pointer to a field_def type.
!!
!> Allocate and initialize a new field in parent_p list.
!! Return a pointer to the field on success, or a null pointer
!! on failure.
!! <br>Example usage:
!! @code{.F90}
!! list_p => create_field(parent_p, name)
!! @endcode
function  create_field(parent_p, name)                        &
          result (list_p)
type (field_def), pointer    :: list_p
type (field_def), pointer    :: parent_p !< A pointer to the parent of the field that is to be created
character(len=*), intent(in) :: name !< The name of the field that is to be created

integer                      :: error, out_unit
!        Check for fatal errors which should never arise
out_unit = stdout()
if (.not. associated(parent_p) .or. name .eq. ' ') then
  nullify(list_p)
  return
endif

!        Allocate space for the new list
allocate(list_p, stat = error)
if (error .ne. 0) then
  write (out_unit,*) trim(error_header), 'Error ', error,       &
       ' allocating memory for list ', trim(name)
  nullify(list_p)
  return
endif
!        Initialize the new field
list_p%name = name

nullify(list_p%next)
list_p%prev => parent_p%last_field
nullify(list_p%first_field)
nullify(list_p%last_field)
list_p%length = 0
list_p%field_type = null_type
list_p%max_index = 0
list_p%array_dim = 0
if (allocated(list_p%i_value))  deallocate(list_p%i_value)
if (allocated(list_p%l_value))  deallocate(list_p%l_value)
if (allocated(list_p%r_value))  deallocate(list_p%r_value)
if (allocated(list_p%s_value))  deallocate(list_p%s_value)
!        If this is the first field in the parent, then set the pointer
!        to it, otherwise, update the "next" pointer for the last list
if (parent_p%length .le. 0) then
  parent_p%first_field => list_p
else
  parent_p%last_field%next => list_p
endif
!        Update the pointer for the last list in the parent
parent_p%last_field => list_p
!        Update the length for the parent
parent_p%length = parent_p%length + 1
!        Set the new index as the return value
list_p%index = parent_p%length
!        set the pointer to the parent list
list_p%parent => parent_p

end function  create_field

!> @brief This is a function that lists the parameters of a field.
!!
!> Given a pointer to a list, this function prints out the fields, and
!! subfields, if recursive is true, associated with the list.
!!
!! This is most likely to be used through fm_dump_list.
!! <br> Example usage:
!! @code{.F90}
!! success = dump_list(list_p, recursive=.true., depth=0)
!! @endcode
logical recursive function dump_list(list_p, recursive, depth, out_unit) result(success)

  type (field_def), pointer :: list_p !< pointer to the field to be printed out
  logical, intent(in)       :: recursive !< flag to make function recursively print subfields
  integer, intent(in)       :: depth !< Listing will be padded so that 'depth' spaces appear before
                                     !! the field being printed
  integer, intent(in)       :: out_unit !< unit number to print to

  integer                             :: depthp1
  integer                             :: j
  character(len=fm_field_name_len)    :: num, scratch
  type (field_def), pointer           :: this_field_p
  character(len=depth+fm_field_name_len) :: blank

  blank = ' ' ! initialize blank string

  ! Check for a valid list
  success = .false.
  if (.not. associated(list_p)) then
    return
  elseif (list_p%field_type .ne. list_type) then
    return
  endif

  ! set the default return value
  success = .true.

  ! Print the name of this list
  write (out_unit,'(a,a,a)') blank(1:depth), trim(list_p%name), list_sep

  !  Increment the indentation depth
  ! The following max function is to work around an error in the IBM compiler for len_trim
  ! depthp1 = depth + max(len_trim(list_p%name),0) + len_trim(list_sep)
  depthp1 = depth + 6

  this_field_p => list_p%first_field

  do while (associated(this_field_p))

     select case(this_field_p%field_type)
     case(list_type)
       ! If this is a list, then call dump_list
       if (recursive) then
          ! If recursive is true, then this routine will find and dump sub-fields.
          success =  dump_list(this_field_p, .true., depthp1, out_unit)
          if (.not.success) exit ! quit immediately in case of error
       else ! Otherwise it will print out the name of this field.
          write (out_unit,'(a,a,a)') blank(1:depthp1), trim(this_field_p%name), list_sep
       endif

     case(integer_type)
         if (this_field_p%max_index .eq. 0) then
            write (out_unit,'(a,a,a)') blank(1:depthp1),  trim(this_field_p%name), ' = NULL'
         elseif (this_field_p%max_index .eq. 1) then
            write (scratch,*) this_field_p%i_value(1)
            write (out_unit,'(a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), ' = ', &
                   trim(adjustl(scratch))
         else  ! Write out the array of values for this field.
            do j = 1, this_field_p%max_index
               write (scratch,*) this_field_p%i_value(j)
               write (num,*) j
               write (out_unit,'(a,a,a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), &
                      '[', trim(adjustl(num)), '] = ', trim(adjustl(scratch))
           enddo
         endif

     case(logical_type)
         if (this_field_p%max_index .eq. 0) then
            write (out_unit,'(a,a,a)') blank(1:depthp1),  trim(this_field_p%name), ' = NULL'
         elseif (this_field_p%max_index .eq. 1) then
            write (scratch,'(l1)') this_field_p%l_value(1)
            write (out_unit,'(a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), ' = ', &
                   trim(adjustl(scratch))
         else  ! Write out the array of values for this field.
            do j = 1, this_field_p%max_index
               write (scratch,'(l1)') this_field_p%l_value(j)
               write (num,*) j
               write (out_unit,'(a,a,a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), &
                      '[', trim(adjustl(num)), '] = ', trim(adjustl(scratch))
            enddo
         endif

     case(real_type)
         if (this_field_p%max_index .eq. 0) then
            write (out_unit,'(a,a,a)') blank(1:depthp1),  trim(this_field_p%name), ' = NULL'
         elseif (this_field_p%max_index .eq. 1) then
            write (scratch,*) this_field_p%r_value(1)
            write (out_unit,'(a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), ' = ', &
                   trim(adjustl(scratch))
         else  ! Write out the array of values for this field.
            do j = 1, this_field_p%max_index
               write (scratch,*) this_field_p%r_value(j)
               write (num,*) j
               write (out_unit,'(a,a,a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), &
                    '[', trim(adjustl(num)), '] = ', trim(adjustl(scratch))
            end do
         endif

     case(string_type)
         if (this_field_p%max_index .eq. 0) then
            write (out_unit,'(a,a,a)') blank(1:depthp1),  trim(this_field_p%name), ' = NULL'
         elseif (this_field_p%max_index .eq. 1) then
            write (out_unit,'(a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), ' = ', &
                   ''''//trim(this_field_p%s_value(1))//''''
         else  ! Write out the array of values for this field.
            do j = 1, this_field_p%max_index
               write (num,*) j
               write (out_unit,'(a,a,a,a,a,a)') blank(1:depthp1), trim(this_field_p%name), &
                      '[', trim(adjustl(num)), '] = ', ''''//trim(this_field_p%s_value(j))//''''
            enddo
         endif

     case default
         success = .false.
         exit

     end select

     this_field_p => this_field_p%next
  enddo

end function dump_list

!> @brief A subroutine that splits a listname into a path and a base.
!!
!> Find the base name for a list by splitting the list name into
!! a path and base. The base is the last field within name, while the
!! path is the preceding section of name. The base string can then be
!! used to query for values associated with name.
subroutine find_base(name, path, base)

character(len=*), intent(in)  :: name !< list name for a field
character(len=*), intent(out) :: path !< path of the base field
character(len=*), intent(out) :: base !< A string which can be used to query for values associated with name

integer :: i
integer :: length

!        Check for the last occurrence of the list separator in name
! The following max function is to work around an error in the IBM compiler for len_trim
length = max(len_trim(name),0)
if (length .eq. 0) then

   !       Empty name, so return empty path and base
   path = ' '
   base = ' '
else
   !       Remove trailing list separators
   do while (name(length:length) .eq. list_sep)
      length = length - 1
      if (length .eq. 0) then
         exit
      endif
   enddo
   if (length .eq. 0) then

      !       Name only list separators, so return empty path and base
      path = ' '
      base = ' '
   else
      !       Check for the last occurrence of the list separator in name
      i = index(name(1:length), list_sep, back = .true.)
      if (i .eq. 0) then
         !       no list separators in the path, so return an empty path
         !       and name as the base
         path = ' '
         base = name(1:length)
      else
         !       Found a list separator, so return the part up to the last
         !       list separator in path, and the remainder in base
         path = name(1:i)
         base = name(i+1:length)
      endif
   endif
endif

end subroutine find_base

!> @brief Find and return a pointer to the field in the specified
!! list. Return a null pointer on error.
!!
!> Find and return a pointer to the field in the specified
!! list. Return a null pointer on error. Given a pointer to a field,
!! this function searchs for "name" as a sub field.
!> @returns A pointer to the field corresponding to "name" or an unassociated pointer if the field
!! name does not exist.
function find_field(name, this_list_p)                                &
        result (field_p)
type (field_def), pointer    :: field_p
character(len=*), intent(in) :: name !< The name of a field that the user wishes to find
type (field_def), pointer    :: this_list_p !< A pointer to a list which the user wishes to search
                                            !! for a field "name".

type (field_def), pointer, save    :: temp_p


nullify (field_p)

if (name .eq. '.') then

!        If the field is '.' then return this list
  field_p => this_list_p
elseif (name .eq. '..') then
!        If the field is '..' then return the parent list
  field_p => this_list_p%parent
else
!        Loop over each field in this list
  temp_p => this_list_p%first_field

  do while (associated(temp_p))
!        If the name matches, then set the return pointer and exit
!        the loop
    if (temp_p%name .eq. name) then
      field_p => temp_p
      exit
    endif

    temp_p => temp_p%next

  enddo
endif

end function find_field

!> @brief Find the first list for a name by splitting the name into
!!    a head and the rest.
!!
!> Find the first list for a name by splitting the name into a head and the
!! rest. The head is the first field within name, while rest is the remaining
!! section of name. The head string can then be used to find other fields that
!! may be associated with name.
subroutine find_head(name, head, rest)

character(len=*), intent(in)  :: name !< The name of a field of interest
character(len=*), intent(out) :: head !< the first field within name
character(len=*), intent(out) :: rest !< the remaining section of name

integer        :: i
!        Check for the first occurrence of the list separator in name
i = index(name, list_sep)
!        Check for additional consecutive list separators and return
!        those also
do while (i .le. len(name))
  if (name(i+1:i+1) .eq. list_sep) then
    i = i + 1
  else
    exit
  endif
enddo

if (i .eq. 0) then
!        no list separators in the path, so return an empty head and
!        name as the rest
  head = ' '
  rest = name
elseif (i .eq. len(name)) then
!        The last character in name is a list separator, so return name
!        as head and an empty rest
  head = name
  rest = ' '
else
!        Found a list separator, so return the part up to the list
!        separator in head, and the remainder in rest
  head = name(1:i)
  rest = name(i+1:)
endif

end subroutine find_head

!> @brief Find and return a pointer to the specified list, relative to
!!    relative_p. Return a null pointer on error.
!!
!> This function, when supplied a pointer to a field and a name of a second
!! field relative to that pointer, will find a list and return the pointer to
!! the second field. If create is .true. and the second field does not exist,
!! it will be created.
!> @returns A pointer to the list to be returned
function find_list(path, relative_p, create)                    &
        result (list_p)
type (field_def), pointer        :: list_p
character(len=*), intent(in)     :: path !< path to the list of interest
type (field_def), pointer        :: relative_p !< pointer to the list to which "path" is relative to
logical,          intent(in)     :: create !< If the list does not exist, it will be created if set to true

character(len=FMS_PATH_LEN)  :: working_path
character(len=FMS_PATH_LEN)  :: rest
character(len=fm_field_name_len) :: this_list
integer                          :: i, out_unit
type (field_def), pointer, save  :: working_path_p
type (field_def), pointer, save  :: this_list_p

out_unit = stdout()
nullify(list_p)
!        If the path is empty, then return the relative list
if (path .eq. ' ') then

  list_p => relative_p

else
!        If a fully qualified path is given (i.e., starts with the
!        list separator) then do everything relative to root,
!        otherwise, do everything relative to relative list.
  if (path(1:1) .eq. list_sep) then
    working_path_p => root_p
    working_path = path(2:)
  else
    working_path_p => relative_p
    working_path = path
  endif
!        Loop over each field in the path
  do while (working_path .ne. ' ')
!        Get the first list in the working path
    call find_head(working_path, this_list, rest)
!        If the first list is empty, then the 'rest' should hold the
!        final field in the path
    if (this_list .eq. ' ') then
      this_list = rest
      rest = ' '
    endif
!        Strip off trailing list separators
    i = len_trim(this_list)
    do while (i .gt. 0 .and. this_list(i:i) .eq. list_sep)
      this_list(i:i) = ' '
      i = i - 1
    enddo
!        Find a pointer to this field in the working list
    this_list_p => find_field(this_list, working_path_p)

    if (.not. associated(this_list_p)) then
      if (create) then
!        Create the list if so requested
        this_list_p => make_list(working_path_p, this_list)
        if (.not. associated(this_list_p)) then
          nullify(list_p)
          return
        endif
      else
!        Otherwise, return an error

        nullify(list_p)
        return
      endif
    endif
!        Make sure that the field found is a list, and if so, proceed to
!        the next field in the path, otherwise, return an error
    if (this_list_p%field_type .eq. list_type) then
      working_path_p => this_list_p
      working_path = rest
    else
      nullify(list_p)
      return
    endif
  enddo
  list_p => working_path_p
endif

end function find_list

!> @brief Change the current list. Return true on success, false otherwise
!!
!> This function changes the currect list to correspond to the list named name.
!! If the first character of name is the list separator (/) then the list will
!! search for "name" starting from the root of the field tree. Otherwise it
!! will search for name starting from the current list.
!! @return A flag to indicate operation success, true = no errors
function fm_change_list(name)                                        &
        result (success)
logical        :: success
character(len=*), intent(in)  :: name !< name of a list to change to

type (field_def), pointer, save :: temp_p
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Find the list if path is not empty
temp_p => find_list(name, current_list_p, .false.)

if (associated(temp_p)) then
  current_list_p => temp_p
  success = .true.
else
  success = .false.
endif

end function fm_change_list

!> @brief Change the root list
!!
!> This function changes the root of the field tree to correspond to the
!! field named name. An example of a use of this would be if code is
!! interested in a subset of fields with a common base. This common base
!! could be set using fm_change_root and fields could be referenced using
!! this root.
!!
!! This function should be used in conjunction with fm_return_root.
!! @return A flag to indicate operation success, true = no errors
function  fm_change_root(name)                                        &
          result (success)
logical        :: success
character(len=*), intent(in)  :: name !< name of the field which the user wishes to become the root.

type (field_def), pointer, save :: temp_list_p
integer :: out_unit
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
out_unit = stdout()
!        Must supply a field field name
if (name .eq. ' ') then
  success = .false.
  return
endif
!        Get a pointer to the list
temp_list_p => find_list(name, current_list_p, .false.)

if (associated(temp_list_p)) then
!        restore the saved root values if we've already changed root
  if (save_root_name .ne. ' ') then
    root_p%name = save_root_name
    root_p%parent => save_root_parent_p
  endif
!        set the pointer for the new root field
  root_p => temp_list_p
!        save the new root field's name and parent
  save_root_name = root_p%name
  save_root_parent_p => root_p%parent
!        set the new root name and parent fields to appropriate values
  root_p%name = ' '
  nullify(root_p%parent)
!        set the current list to the new root as it likely is not
!        going to be meaningful anymore
  current_list_p => root_p
  success = .true.
else
!        Couldn't find the list
  success = .false.
endif

end function  fm_change_root

!> @brief A function to list properties associated with a field.
!!
!> This function writes the contents of the field named "name" to stdout.
!! If recursive is present and .true., then this function writes out the
!! contents of any subfields associated with the field named "name".
!! @return A flag to indicate operation success, true = no errors
logical function  fm_dump_list(name, recursive, unit) result (success)
  character(len=*), intent(in)  :: name !< The name of the field for which output is requested.
  logical, intent(in), optional :: recursive !< If present and .true., then a recursive listing of
                                             !! fields will be performed.
  integer, intent(in), optional :: unit !< file to print to

  logical                         :: recursive_t
  type (field_def), pointer, save :: temp_list_p
  integer                         :: out_unit

  if (present(unit)) then
     out_unit = unit
  else
     out_unit = stdout()
  endif

  recursive_t = .false.
  if (present(recursive)) recursive_t = recursive
  if (.not. module_is_initialized) call initialize_module_variables()

  if (name .eq. ' ') then
    ! If list is empty, then dump the current list
    temp_list_p => current_list_p
    success = .true.
  else
    ! Get a pointer to the list
    temp_list_p => find_list(name, current_list_p, .false.)
    if (associated(temp_list_p)) then
       success = .true.
    else
       success = .false.
    endif
  endif
  ! Dump the list
  if (success) then
      success = dump_list(temp_list_p, recursive_t, 0, out_unit)
  endif
end function  fm_dump_list

!> @brief A function to test whether a named field exists.
!!
!> This function determines is a field exists, relative to the current list,
!! and returns true if the list exists, false otherwise.
!! @return A flag to indicate operation success, true = no errors
function fm_exists(name)                                                &
        result (success)
logical        :: success
character(len=*), intent(in) :: name !< The name of the field that is being queried

type (field_def), pointer, save :: dummy_p
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Determine whether the field exists
dummy_p => get_field(name, current_list_p)
success = associated(dummy_p)

end function fm_exists

!> @brief A function to return the index of a named field.
!!
!> Returns the index for name, returns the parameter NO_FIELD if it does not
!! exist. If the first character of the named field is the list peparator,
!! then the named field will be relative to the root of the field tree.
!! Otherwise the named field will be relative to the current list.
!> @returns index of the named field if it exists, otherwise the parameter NO_FIELD
function  fm_get_index(name)                        &
          result (index)
integer        :: index
character(len=*), intent(in) :: name !< The name of a field that the user wishes to get an index for

type (field_def), pointer, save :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field field name
if (name .eq. ' ') then
  index = NO_FIELD
  return
endif
!        Get a pointer to the field
temp_field_p => get_field(name, current_list_p)
if (associated(temp_field_p)) then
!        Set the index
  index = temp_field_p%index
else
  index = NO_FIELD
endif

end function  fm_get_index

!> @brief A function to return the full path of the current list.
!!
!> This function returns the full path for the current list. A blank
!! path indicates an error condition has occurred.
!> @returns The path corresponding to the current list
function  fm_get_current_list()                                        &
          result (path)
character(len=FMS_PATH_LEN) :: path

type (field_def), pointer, save :: temp_list_p
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Set a pointer to the current list and proceed
!        up the tree, filling in the name as we go
temp_list_p => current_list_p
path = ' '

do while (associated(temp_list_p))
!        Check whether we are at the root field--it is the
!        only field with a blank name
  if (temp_list_p%name .eq. ' ') then
    exit
  endif
!        Append the name to the path
  path = list_sep // trim(temp_list_p%name) // path
!        Point to the next field
  temp_list_p => temp_list_p%parent
enddo

if (.not. associated(temp_list_p)) then
!        The pointer is not associated, indicating an error has
!        occurred, so set the path accordingly
  path = ' '
elseif (path .eq. ' ') then
!        If path is empty, then the current list must be root,
!        so set path accordingly
  path = list_sep
endif

end function  fm_get_current_list

!> @brief A function to return how many elements are contained within the named
!! list or entry.
!!
!> This function returns the list or entry length for the named list or entry.
!! If the named field or entry does not exist, a value of 0 is returned.
!> @returns The number of elements that the field name has.
function  fm_get_length(name)                        &
          result (length)
integer                      :: length
character(len=*), intent(in) :: name !< The name of a list or entry that the user wishes to get the length of

type (field_def), pointer, save :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field name
if (name .eq. ' ') then
  length = 0
  return
endif
!        Get a pointer to the field
temp_field_p => get_field(name, current_list_p)

if (associated(temp_field_p)) then
!        Set the field length
  if (temp_field_p%field_type .eq. list_type) then
    length = temp_field_p%length
  else
    length = temp_field_p%max_index
  endif
else
  length = 0
endif

end function  fm_get_length

!> @brief A function to return the type of the named field
!!
!> This function returns the type of the field for name.
!! This indicates whether the named field is a "list" (has children fields),
!! or has values of type "integer", "real", "logical" or "string".
!! If it does not exist it returns a blank string.
!> @returns A string containing the type of the named field
function  fm_get_type(name)                        &
          result (name_field_type)
character(len=8)             :: name_field_type
character(len=*), intent(in) :: name !< The name of a field that the user wishes to find the type of

type (field_def), pointer, save :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field name
if (name .eq. ' ') then
  name_field_type = ' '
  return
endif
!        Get a pointer to the field
temp_field_p => get_field(name, current_list_p)

if (associated(temp_field_p)) then
!        Set the field type
  name_field_type = field_type_name(temp_field_p%field_type)
else
  name_field_type = ' '
endif

end function  fm_get_type

!> @returns A flag to indicate whether the function operated with (false) or without
!! (true) errors.
function  fm_get_value_integer(name, get_ival, index)                 &
          result (success)
logical                                :: success
character(len=*), intent(in)           :: name !< The name of a field that the user wishes to get a value for.
integer,          intent(out)          :: get_ival !< The value associated with the named field.
integer,          intent(in), optional :: index !< An optional index to retrieve a single value from an array.

integer                         :: index_t
type (field_def), pointer, save :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field field name
if (name .eq. ' ') then
  get_ival = 0
  success = .false.
  return
endif
!        Set index to retrieve
if (present(index)) then
  index_t = index
else
  index_t = 1
endif
!        Get a pointer to the field
temp_field_p => get_field(name, current_list_p)

if (associated(temp_field_p)) then
!        check that the field is the correct type
  if (temp_field_p%field_type .eq. integer_type) then
    if (index_t .lt. 1 .or. index_t .gt. temp_field_p%max_index) then
!        Index is not positive or index too large
      get_ival = 0
      success = .false.
    else
!        extract the value
      get_ival = temp_field_p%i_value(index_t)
      success = .true.
    endif
  else
!        Field not corrcet type
    get_ival = 0
    success = .false.
  endif
else
  get_ival = 0
  success = .false.
endif

end function  fm_get_value_integer

!> @returns A flag to indicate whether the function operated with (false) or without
!! (true) errors.
function  fm_get_value_logical(name, get_lval, index)                 &
          result (success)
logical                                :: success
character(len=*), intent(in)           :: name !< The name of a field that the user wishes to get a value for.
logical,          intent(out)          :: get_lval !< The value associated with the named field
integer,          intent(in), optional :: index !< An optional index to retrieve a single value from an array.

integer                         :: index_t
type (field_def), pointer, save :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field field name
if (name .eq. ' ') then
  get_lval = .false.
  success = .false.
  return
endif
!        Set index to retrieve
if (present(index)) then
  index_t = index
else
  index_t = 1
endif
!        Get a pointer to the field
temp_field_p => get_field(name, current_list_p)

if (associated(temp_field_p)) then
!        check that the field is the correct type
  if (temp_field_p%field_type .eq. logical_type) then

    if (index_t .lt. 1 .or. index_t .gt. temp_field_p%max_index) then
!        Index is not positive or too large
      get_lval = .false.
      success = .false.
    else
!        extract the value
      get_lval = temp_field_p%l_value(index_t)
      success = .true.
    endif
  else
!        Field not correct type
    get_lval = .false.
    success = .false.
  endif
else
  get_lval = .false.
  success = .false.
endif

end function  fm_get_value_logical

!> @returns A flag to indicate whether the function operated with (false) or without
!! (true) errors.
function  fm_get_value_string(name, get_sval, index)                 &
          result (success)
logical                                :: success
character(len=*), intent(in)           :: name !< The name of a field that the user wishes to get a value for.
character(len=*), intent(out)          :: get_sval !< The value associated with the named field
integer,          intent(in), optional :: index !< An optional index to retrieve a single value from an array.

integer                         :: index_t
type (field_def), pointer, save :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field field name
if (name .eq. ' ') then
  get_sval = ''
  success = .false.
  return
endif
!        Set index to retrieve
if (present(index)) then
  index_t = index
else
  index_t = 1
endif
!        Get a pointer to the field
temp_field_p => get_field(name, current_list_p)

if (associated(temp_field_p)) then
!        check that the field is the correct type
  if (temp_field_p%field_type .eq. string_type) then
    if (index_t .lt. 1 .or. index_t .gt. temp_field_p%max_index) then
!        Index is not positive or is too large
      get_sval = ''
      success = .false.
    else
!        extract the value
      get_sval = temp_field_p%s_value(index_t)
        success = .true.
    endif
  else
!        Field not correct type
    get_sval = ''
    success = .false.
  endif
else
  get_sval = ''
  success = .false.
endif

end function  fm_get_value_string

!> Iterates through the given list
!> @returns A flag to indicate whether the function operated with (FALSE)
!! or without (TRUE) errors
function  fm_loop_over_list_old(list, name, field_type, index)        &
          result (success)
logical                                      :: success
character(len=*),                intent(in)  :: list !< Name of a list to loop over
character(len=*),                intent(out) :: name !< name of a field from list
character(len=fm_type_name_len), intent(out) :: field_type !< type of a list entry
integer,                         intent(out) :: index !< index of the field within the list

integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif

if (list .eq. loop_list .and. associated(loop_list_p)) then
!        We've already started this loop, so continue on
  loop_list_p => loop_list_p%next
  success = set_list_stuff()
elseif (list .eq. ' ') then
!        If list is empty, then loop over the current list
  loop_list = ' '
  loop_list_p => current_list_p%first_field
  success = set_list_stuff()
else
!        Get a pointer to the list
  loop_list = list
  loop_list_p => find_list(loop_list, current_list_p, .false.)
  if (associated(loop_list_p)) then
    loop_list_p => loop_list_p%first_field
    success = set_list_stuff()
  else
    success = .false.
  endif
endif

return

contains

!> If the the pointer matches to the right list,
!! extract the field information.  Used in fm_loop_over_list
!> @returns A flag to indicate whether the function operated with (FALSE)
!! or without (TRUE) errors
function  set_list_stuff()                                                &
          result (success)

  logical        :: success

  if (associated(loop_list_p)) then
    name = loop_list_p%name
    field_type = field_type_name(loop_list_p%field_type)
    index = loop_list_p%index
    success = .true.
  else
    name = ' '
    field_type = ' '
    index = 0
    success = .false.
    loop_list = ' '
  endif

end function  set_list_stuff

end function  fm_loop_over_list_old

!> given a name of the list, prepares an iterator over the list content.
!! If the name of the given list is blank, then the current list is used
subroutine fm_init_loop(loop_list, iter)
  character(len=*)       , intent(in)  :: loop_list !< name of the list to iterate over
  type(fm_list_iter_type), intent(out) :: iter     !< loop iterator

  if (.not.module_is_initialized) call initialize_module_variables

  if (loop_list==' ') then ! looping over current list
     iter%ptr => current_list_p%first_field
  else
     iter%ptr => find_list(loop_list,current_list_p,.false.)
     if (associated(iter%ptr)) iter%ptr => iter%ptr%first_field
  endif
end subroutine fm_init_loop

!> given a list iterator, returns information about curren list element
!! and advances the iterator to the next list element. At the end of the
!! list, returns FALSE
function fm_loop_over_list_new(iter, name, field_type, index) &
         result (success) ; logical success
  type (fm_list_iter_type), intent(inout) :: iter !< list iterator
  character(len=*), intent(out) :: name       !< name of the current list item
  character(len=*), intent(out) :: field_type !< type of the field
  integer         , intent(out) :: index      !< index in the list

  if (.not.module_is_initialized) call initialize_module_variables
  if (associated(iter%ptr)) then
     name       = iter%ptr%name
     field_type = field_type_name(iter%ptr%field_type)
     index      = iter%ptr%index
     success    = .TRUE.
     iter%ptr => iter%ptr%next
  else
     name       = ' '
     field_type = ' '
     index      = 0
     success    = .FALSE.
  endif
end function fm_loop_over_list_new

!> @brief A function to create a new list
!!
!> Allocate and initialize a new list and return the index of the list. If an
!! error occurs return the parameter NO_FIELD.
!> @return integer index of the newly created list
function  fm_new_list(name, create, keep)                        &
          result (index)
integer                                :: index
character(len=*), intent(in)           :: name !< Name of a list that user wishes to create
logical,          intent(in), optional :: create !< If present and true, create the list if it does not exist
logical,          intent(in), optional :: keep !< If present and true, make this list the current list

logical                          :: create_t
logical                          :: keep_t
character(len=FMS_PATH_LEN)  :: path
character(len=fm_field_name_len) :: base
type (field_def), pointer, save  :: temp_list_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field list name
if (name .eq. ' ') then
  index = NO_FIELD
  return
endif
!        Check for optional arguments
if (present(create)) then
  create_t = create
else
  create_t = .false.
endif

if (present(keep)) then
  keep_t = keep
else
  keep_t = .false.
endif
!        Get a pointer to the parent list
call find_base(name, path, base)

temp_list_p => find_list(path, current_list_p, create_t)

if (associated(temp_list_p)) then
!        Create the list
  temp_list_p => make_list(temp_list_p, base)
  if (associated(temp_list_p)) then
!        Make this list the current list, if requested
    if (keep_t) then
      current_list_p => temp_list_p
    endif
    index = temp_list_p%index
  else
    index = NO_FIELD
  endif
else
  index = NO_FIELD
endif

end function  fm_new_list

!> @brief Assigns a given value to a given field
!> @returns An index for the named field
function  fm_new_value_integer(name, new_ival, create, index, append)     &
          result (field_index)
integer                                :: field_index
character(len=*), intent(in)           :: name !< The name of a field that the user wishes to create
                                               !! a value for.
integer,          intent(in)           :: new_ival !< The value that the user wishes to apply to the
                                                !! named field.
logical,          intent(in), optional :: create !< If present and .true., then a value for this
                                                 !! field will be created.
integer,          intent(in), optional :: index !< The index to an array of values that the user
                                                !! wishes to apply a new value.
logical,          intent(in), optional :: append !< If present and .true., then append the value to
      !! an array of the present values. If present and .true., then index cannot be greater than 0.

logical                          :: create_t
integer                          :: i
integer                          :: index_t
integer, pointer, dimension(:)   :: temp_i_value
character(len=FMS_PATH_LEN)  :: path
character(len=fm_field_name_len) :: base
type (field_def), pointer, save  :: temp_list_p
type (field_def), pointer, save  :: temp_field_p
integer                          :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field name
if (name .eq. ' ') then
  field_index = NO_FIELD
  return
endif
!        Check for optional arguments
if (present(create)) then
  create_t = create
else
  create_t = .false.
endif
!        Check that append is not true and index non-positive
if (present(index) .and. present(append)) then
  if (append .and. index .gt. 0) then
    field_index = NO_FIELD
    return
  endif
endif
!        Set index to define
if (present(index)) then
  index_t = index
  if (index_t .lt. 0) then
!        Index is negative
    field_index = NO_FIELD
    return
  endif
else
  index_t = 1
endif
!        Get a pointer to the parent list
call find_base(name, path, base)
temp_list_p => find_list(path, current_list_p, create_t)

if (associated(temp_list_p)) then
  temp_field_p => find_field(base, temp_list_p)
  if (.not. associated(temp_field_p)) then
!        Create the field if it doesn't exist
    temp_field_p => create_field(temp_list_p, base)
  endif
  if (associated(temp_field_p)) then
!        Check if the field_type is the same as previously
!        If not then reset max_index to 0
    if (temp_field_p%field_type == real_type ) then
       ! promote integer input to real
       ! all real field values are stored as r8_kind
       field_index = fm_new_value(name, real(new_ival,r8_kind), create, index, append)
       return
    else if (temp_field_p%field_type /= integer_type ) then
      !  slm: why would we reset index? Is it not an error to have a "list" defined
      !  with different types in more than one place?
      temp_field_p%max_index = 0
    endif
!        Assign the type
    temp_field_p%field_type = integer_type
!        Set the index if appending
    if (present(append)) then
      if (append) then
        index_t = temp_field_p%max_index + 1
      endif
    endif

    if (index_t .gt. temp_field_p%max_index + 1) then
!        Index too large
      field_index = NO_FIELD
      return

    elseif (index_t .eq. 0 .and.                                &
            temp_field_p%max_index .gt. 0) then
!        Can't set non-null field to null
      field_index = NO_FIELD
      return

    elseif (.not. allocated(temp_field_p%i_value) .and.        &
            index_t .gt. 0) then
!        Array undefined, so allocate the array
      allocate(temp_field_p%i_value(1))
      temp_field_p%max_index = 1
      temp_field_p%array_dim = 1
    elseif (index_t .gt. temp_field_p%array_dim) then
!        Array is too small, so allocate new array and copy over
!        old values
      temp_field_p%array_dim = temp_field_p%array_dim + array_increment
      allocate (temp_i_value(temp_field_p%array_dim))
      do i = 1, temp_field_p%max_index
        temp_i_value(i) = temp_field_p%i_value(i)
      enddo
      if (allocated(temp_field_p%i_value)) deallocate(temp_field_p%i_value)
      temp_field_p%i_value = temp_i_value
      temp_field_p%max_index = index_t
    endif
!        Assign the value and set the field_index for return
!        for non-null fields (index_t > 0)
    if (index_t .gt. 0) then
      temp_field_p%i_value(index_t) = new_ival
      if (index_t .gt. temp_field_p%max_index) then
        temp_field_p%max_index = index_t
      endif
    endif
    field_index = temp_field_p%index

  else
    field_index = NO_FIELD
  endif
else
  field_index = NO_FIELD
endif

end function  fm_new_value_integer

!> @brief Assigns a given value to a given field
!> @returns An index for the named field
function  fm_new_value_logical(name, new_lval, create, index, append) &
          result (field_index)
integer                                :: field_index
character(len=*), intent(in)           :: name !< The name of a field that the user wishes to create
                                               !! a value for.
logical,          intent(in)           :: new_lval !< The value that the user wishes to apply to the
                                                !! named field.
logical,          intent(in), optional :: create !< If present and .true., then a value for this
                                                 !! field will be created.
integer,          intent(in), optional :: index !< The index to an array of values that the user
                                                !! wishes to apply a new value.
logical,          intent(in), optional :: append !< If present and .true., then append the value to
      !! an array of the present values. If present and .true., then index cannot be greater than 0.

character(len=FMS_PATH_LEN)      :: path
character(len=fm_field_name_len)     :: base
integer                              :: i
integer                              :: index_t
logical                              :: create_t
logical, dimension(:), pointer       :: temp_l_value
type (field_def),      pointer, save :: temp_list_p
type (field_def),      pointer, save :: temp_field_p
integer                              :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field name
if (name .eq. ' ') then
  field_index = NO_FIELD
  return
endif
!        Check for optional arguments
if (present(create)) then
  create_t = create
else
  create_t = .false.
endif
!        Check that append is not true and index greater than 0
if (present(index) .and. present(append)) then
  if (append .and. index .gt. 0) then
    field_index = NO_FIELD
    return
  endif
endif
!        Set index to define
if (present(index)) then
  index_t = index
  if (index_t .lt. 0) then
!        Index is negative
    field_index = NO_FIELD
    return
  endif
else
  index_t = 1
endif
!        Get a pointer to the parent list
call find_base(name, path, base)
temp_list_p => find_list(path, current_list_p, create_t)

if (associated(temp_list_p)) then
  temp_field_p => find_field(base, temp_list_p)
  if (.not. associated(temp_field_p)) then
!        Create the field if it doesn't exist
    temp_field_p => create_field(temp_list_p, base)
  endif
  if (associated(temp_field_p)) then
!        Check if the field_type is the same as previously
!        If not then reset max_index to 0
    if (temp_field_p%field_type /= logical_type ) then
        temp_field_p%max_index = 0
    endif
!        Assign the type
    temp_field_p%field_type = logical_type
!        Set the index if appending
    if (present(append)) then
      if (append) then
        index_t = temp_field_p%max_index + 1
      endif
    endif

    if (index_t .gt. temp_field_p%max_index + 1) then
!        Index too large
      field_index = NO_FIELD
      return

    elseif (index_t .eq. 0 .and.                                &
            temp_field_p%max_index .gt. 0) then
!        Can't set non-null field to null
      field_index = NO_FIELD
      return

    elseif (.not. allocated(temp_field_p%l_value) .and.        &
            index_t .gt. 0) then
!        Array undefined, so allocate the array
      allocate(temp_field_p%l_value(1))
      temp_field_p%max_index = 1
      temp_field_p%array_dim = 1

    elseif (index_t .gt. temp_field_p%array_dim) then
!        Array is too small, so allocate new array and copy over
!        old values
      temp_field_p%array_dim = temp_field_p%array_dim + array_increment
      allocate (temp_l_value(temp_field_p%array_dim))
      do i = 1, temp_field_p%max_index
        temp_l_value(i) = temp_field_p%l_value(i)
      enddo
      if (allocated(temp_field_p%l_value)) deallocate(temp_field_p%l_value)
      temp_field_p%l_value = temp_l_value
      temp_field_p%max_index = index_t

    endif
!        Assign the value and set the field_index for return
!        for non-null fields (index_t > 0)
    if (index_t .gt. 0) then
      temp_field_p%l_value(index_t) = new_lval
      if (index_t .gt. temp_field_p%max_index) then
        temp_field_p%max_index = index_t
      endif
    endif
    field_index = temp_field_p%index
  else
    field_index = NO_FIELD
  endif
else
  field_index = NO_FIELD
endif

end function  fm_new_value_logical

!> @brief Assigns a given value to a given field
!> @returns An index for the named field
function  fm_new_value_string(name, new_sval, create, index, append) &
          result (field_index)
integer                                :: field_index
character(len=*), intent(in)           :: name !< The name of a field that the user wishes to create
                                               !! a value for.
character(len=*), intent(in)           :: new_sval !< The value that the user wishes to apply to the
                                                !! named field.
logical,          intent(in), optional :: create !< If present and .true., then a value for this
                                                 !! field will be created.
integer,          intent(in), optional :: index !< The index to an array of values that the user
                                                !! wishes to apply a new value.
logical,          intent(in), optional :: append !< If present and .true., then append the value to

character(len=fm_string_len), dimension(:), pointer :: temp_s_value
character(len=FMS_PATH_LEN)                     :: path
character(len=fm_field_name_len)                    :: base
integer                                             :: i
integer                                             :: index_t
logical                                             :: create_t
type (field_def),                     save, pointer :: temp_list_p
type (field_def),                     save, pointer :: temp_field_p
integer                         :: out_unit

out_unit = stdout()
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Must supply a field name
if (name .eq. ' ') then
  field_index = NO_FIELD
  return
endif
!        Check for optional arguments
if (present(create)) then
  create_t = create
else
  create_t = .false.
endif
!        Check that append is not true and index greater than 0
if (present(index) .and. present(append)) then
  if (append .and. index .gt. 0) then
    field_index = NO_FIELD
    return
  endif
endif
!        Set index to define
if (present(index)) then
  index_t = index
  if (index_t .lt. 0) then
!        Index is negative
    field_index = NO_FIELD
    return
  endif
else
  index_t = 1
endif
!        Get a pointer to the parent list
call find_base(name, path, base)
temp_list_p => find_list(path, current_list_p, create_t)

if (associated(temp_list_p)) then
  temp_field_p => find_field(base, temp_list_p)
  if (.not. associated(temp_field_p)) then
!        Create the field if it doesn't exist
    temp_field_p => create_field(temp_list_p, base)
  endif
  if (associated(temp_field_p)) then
!        Check if the field_type is the same as previously
!        If not then reset max_index to 0
    if (temp_field_p%field_type /= string_type ) then
        temp_field_p%max_index = 0
    endif
!        Assign the type
    temp_field_p%field_type = string_type
!        Set the index if appending
    if (present(append)) then
      if (append) then
        index_t = temp_field_p%max_index + 1
      endif
    endif

    if (index_t .gt. temp_field_p%max_index + 1) then
!        Index too large
      field_index = NO_FIELD
      return

    elseif (index_t .eq. 0 .and.                                &
            temp_field_p%max_index .gt. 0) then
!        Can't set non-null field to null
      field_index = NO_FIELD
      return

    elseif (.not.allocated(temp_field_p%s_value) .and.        &
            index_t .gt. 0) then
!        Array undefined, so allocate the array
      allocate(temp_field_p%s_value(1))
      temp_field_p%max_index = 1
      temp_field_p%array_dim = 1

    elseif (index_t .gt. temp_field_p%array_dim) then
!        Array is too small, so allocate new array and copy over
!        old values
      temp_field_p%array_dim = temp_field_p%array_dim + array_increment
      allocate (temp_s_value(temp_field_p%array_dim))
      do i = 1, temp_field_p%max_index
        temp_s_value(i) = temp_field_p%s_value(i)
      enddo
      if (allocated(temp_field_p%s_value)) deallocate(temp_field_p%s_value)
      temp_field_p%s_value = temp_s_value
      temp_field_p%max_index = index_t

    endif
!        Assign the value and set the field_index for return
!        for non-null fields (index_t > 0)
    if (index_t .gt. 0) then
      temp_field_p%s_value(index_t) = new_sval
      if (index_t .gt. temp_field_p%max_index) then
        temp_field_p%max_index = index_t
      endif
    endif
    field_index = temp_field_p%index
  else
!        Error in making the field
    field_index = NO_FIELD
  endif
else
!        Error following the path
  field_index = NO_FIELD
endif

end function  fm_new_value_string


!> Resets the loop variable. For use in conjunction with fm_loop_over_list.
subroutine  fm_reset_loop
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        Reset the variables
loop_list = ' '
nullify(loop_list_p)

end subroutine  fm_reset_loop

!> Return the root list to the value at initialization.
!!
!> For use in conjunction with fm_change_root.
!!
!! Users should use this routine before leaving their routine if they
!! previously used fm_change_root.
subroutine  fm_return_root
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif
!        restore the saved values to the current root
root_p%name = save_root_name
root_p%parent => save_root_parent_p
!        set the pointer to the original root field
root_p => root
!        reset the save root name and parent variables
save_root_name = ' '
nullify(save_root_parent_p)

end subroutine  fm_return_root

!> Return a pointer to the field if it exists relative to this_list_p,
!! null otherwise
!! @returns A pointer to the field name
function get_field(name, this_list_p)                                        &
        result (list_p)
type (field_def), pointer        :: list_p
character(len=*), intent(in)     :: name !< The name of a list that the user wishes to get information for
type (field_def), pointer        :: this_list_p !< A pointer to a list that serves as the base point
                                                !! for searching for name

character(len=FMS_PATH_LEN)  :: path
character(len=fm_field_name_len) :: base
type (field_def), pointer, save  :: temp_p

nullify(list_p)
!        Get the path and base for name
call find_base(name, path, base)
!        Find the list if path is not empty
if (path .ne. ' ') then
  temp_p => find_list(path, this_list_p, .false.)
  if (associated(temp_p)) then
    list_p => find_field(base, temp_p)
  else
    nullify(list_p)
  endif
else
  list_p => find_field(base, this_list_p)
endif

end function get_field

!> This function allows a user to rename a field without modifying the
!! contents of the field.
!!
!> Function to modify the name of a field.
!! Should be used with caution.
!! @returns A flag to indicate whether the function operated with (FALSE) or
!!     without (TRUE) errors.
function fm_modify_name(oldname, newname)                                        &
        result (success)
logical                          :: success
character(len=*), intent(in)     :: oldname !< The name of a field that the user wishes to change
                                            !! the name of
character(len=*), intent(in)     :: newname !< The name that the user wishes to change the name of
                                            !! the field to.

character(len=FMS_PATH_LEN)  :: path
character(len=fm_field_name_len) :: base
type (field_def), pointer, save  :: list_p
type (field_def), pointer, save  :: temp_p
!        Get the path and base for name
call find_base(oldname, path, base)
!        Find the list if path is not empty
success = .false.
if (path .ne. ' ') then
  temp_p => find_list(path, current_list_p, .false.)
  if (associated(temp_p)) then
    list_p => find_field(base, temp_p)
    if (associated(list_p)) then
      list_p%name = newname
      success = .true.
    endif
  else
    nullify(list_p)
  endif
else
  list_p => find_field(base, current_list_p)
  if (associated(list_p)) then
    list_p%name = newname
    success = .true.
  endif
endif

end function fm_modify_name

!> A function to initialize the values of the pointers. This will remove
!! all fields and reset the field tree to only the root field.
subroutine initialize_module_variables
  !        Initialize the root field
  integer :: io, ierr !< Error codes when reading the namelist
  integer :: logunit !< Unit number for the log file

  if (.not. module_is_initialized) then

  read (input_nml_file, nml=field_manager_nml, iostat=io)
  ierr = check_nml_error(io,"field_manager_nml")

  logunit = stdlog()
  if (mpp_pe() == mpp_root_pe()) write (logunit, nml=field_manager_nml)

  root_p => root

  field_type_name(integer_type) = 'integer'
  field_type_name(list_type) = 'list'
  field_type_name(logical_type) = 'logical'
  field_type_name(real_type) = 'real'
  field_type_name(string_type) = 'string'

  root%name = ' '
  root%index = 1
  root%parent => root_p

  root%field_type = list_type

  root%length = 0
  nullify(root%first_field)
  nullify(root%last_field)
  root%max_index = 0
  root%array_dim = 0
  if (allocated(root%i_value)) deallocate(root%i_value)
  if (allocated(root%l_value)) deallocate(root%l_value)
  if (allocated(root%r_value)) deallocate(root%r_value)
  if (allocated(root%s_value)) deallocate(root%s_value)

  nullify(root%next)
  nullify(root%prev)

  current_list_p => root

  nullify(loop_list_p)
  loop_list = ' '

  nullify(save_root_parent_p)
  save_root_name = ' '

  module_is_initialized = .true.

endif

end subroutine initialize_module_variables

!> This function creates a new field and returns a pointer to that field.
!!
!> Allocate and initialize a new list in this_list_p list.
!! @return a pointer to the list on success, or a null pointer
!! on failure.
function  make_list(this_list_p, name)                        &
          result (list_p)
type (field_def), pointer    :: list_p
type (field_def), pointer    :: this_list_p !< Base of a list that the user wishes to add a list to
character(len=*), intent(in) :: name !< name of a list that the user wishes to create

type (field_def), pointer, save :: dummy_p
integer                         :: out_unit

out_unit = stdout()
!        Check to see whether there is already a list with
!        this name, and if so, return an error as list names
!        must be unique
dummy_p => find_field(name, this_list_p )
if (associated(dummy_p)) then
!        This list is already specified, return an error
  list_p => dummy_p
  return
endif
!        Create a field for the new list
nullify(list_p)
list_p => create_field(this_list_p, name)
if (.not. associated(list_p)) then
  nullify(list_p)
  return
endif
!        Initialize the new list
list_p%length = 0
list_p%field_type = list_type
if (allocated(list_p%i_value))  deallocate(list_p%i_value)
if (allocated(list_p%l_value))  deallocate(list_p%l_value)
if (allocated(list_p%r_value))  deallocate(list_p%r_value)
if (allocated(list_p%s_value))  deallocate(list_p%s_value)

end function  make_list

!> This is a function that provides the capability to return parameters
!! associated with a field in a pair of strings.
!!
!> Given a name return a list of method names and control strings.
!! This function should return strings similar to those in the field
!! table if a comma delimited format is being used.
!> @return A flag to indicate whether the function operated with (FALSE) or
!! without (TRUE) errors
function fm_query_method(name, method_name, method_control)                &
          result (success)
logical                       :: success
character(len=*), intent(in)  :: name !< name of a list that the user wishes to change to
character(len=*), intent(out) :: method_name !< name of a parameter associated with the named field
character(len=*), intent(out) :: method_control !< value of parameters associated with the named field

character(len=FMS_PATH_LEN) :: path
character(len=FMS_PATH_LEN) :: base
character(len=FMS_PATH_LEN) :: name_loc
logical                         :: recursive_t
type (field_def), pointer, save :: temp_list_p
type (field_def), pointer, save :: temp_value_p
type (field_def), pointer, save :: this_field_p
integer                         :: out_unit

  out_unit = stdout()
  success     = .false.
  recursive_t = .true.
  method_name = " "
  method_control = " "
!        Initialize the field manager if needed
if (.not. module_is_initialized) call initialize_module_variables
name_loc = lowercase(name)
call find_base(name_loc, path, base)

  temp_list_p => find_list(name_loc, current_list_p, .false.)

if (associated(temp_list_p)) then
! Find the entry values for the list.
  success = query_method(temp_list_p, recursive_t, base, method_name, method_control)
else
! This is not a list but it may be a parameter with a value
! If so put the parameter value in method_name.

  temp_value_p => find_list(path, current_list_p, .false.)
  if (associated(temp_value_p)) then
! Find the entry values for this item.
  this_field_p => temp_value_p%first_field

  do while (associated(this_field_p))
    if ( this_field_p%name == base ) then
      method_name = this_field_p%s_value(1)
      method_control = ""
      success = .true.
      exit
    else
      success = .false.
    endif
    this_field_p => this_field_p%next
  enddo

  else
!        Error following the path
    success = .false.
  endif
endif

end function  fm_query_method

!> A private function that can recursively recover values for parameters
!! associated with a field.
!> @return A flag to indicate whether the function operated with (FALSE) or
!! without (TRUE) errors
recursive function query_method(list_p, recursive, name, method_name, method_control) &
          result (success)
logical :: success
type (field_def), pointer     :: list_p !< A pointer to the field that is of interest
logical,          intent(in)  :: recursive !< A flag to enable recursive searching if true
character(len=*), intent(in)  :: name !<  name of a list that the user wishes to change to
character(len=*), intent(out) :: method_name !< name of a parameter associated with the named field
character(len=*), intent(out) :: method_control !< value of parameters associated with the named field

integer                         :: i
character(len=64)               :: scratch
type (field_def), pointer :: this_field_p
integer                         :: out_unit

out_unit = stdout()

!  Check for a valid list
if (.not. associated(list_p) .or. list_p%field_type .ne. list_type) then
  success = .false.
else

  ! set the default return value
  success = .true.

  this_field_p => list_p%first_field

  do while (associated(this_field_p))
    select case(this_field_p%field_type)
    case(list_type)
      ! If this is a list, then this is the method name
      if (recursive) then
        if (.not. query_method(this_field_p, .true., this_field_p%name, method_name, method_control)) then
          success = .false.
          exit
        else
          method_name = trim(method_name)//trim(this_field_p%name)
        endif
      endif

    case(integer_type)
        write (scratch,*) this_field_p%i_value
        call concat_strings(method_control, comma//trim(this_field_p%name)//' = '//trim(adjustl(scratch)))

    case(logical_type)
        write (scratch,'(l1)')this_field_p%l_value
        call concat_strings(method_control, comma//trim(this_field_p%name)//' = '//trim(adjustl(scratch)))

    case(real_type)
        write (scratch,*) this_field_p%r_value
        call concat_strings(method_control, comma//trim(this_field_p%name)//' = '//trim(adjustl(scratch)))

    case(string_type)
        call concat_strings(method_control, comma//trim(this_field_p%name)//' = '//trim(this_field_p%s_value(1)))
        do i = 2, this_field_p%max_index
           call concat_strings(method_control, comma//trim(this_field_p%s_value(i)))
        enddo

    case default
        success = .false.
        exit

    end select
    this_field_p => this_field_p%next
  enddo
endif

end function query_method

!> private function: appends str2 to the end of str1, with length check
subroutine concat_strings(str1,str2)
   character(*), intent(inout) :: str1
   character(*), intent(in)    :: str2

   character(64) :: n1,n2 ! for error reporting

   if (len_trim(str1)+len_trim(str2)>len(str1)) then
      write(n1,*)len(str1)
      write(n2,*)len_trim(str1)+len_trim(str2)
      call mpp_error(FATAL,'length of output string ('//trim(adjustl(n1))&
           //') is not enough for the result of concatenation (len='&
           //trim(adjustl(n2))//')')
   endif
   str1 = trim(str1)//trim(str2)
end subroutine concat_strings

!> A function that allows the user to copy a field and add a suffix to
!! the name of the new field.
!!
!> Given the name of a pre-existing field and a suffix, this function
!! will create a new field. The name of the new field will be that of
!! the old field with a suffix supplied by the user.
!! @return index of the field that has been created by the copy
function fm_copy_list(list_name, suffix, create ) &
         result(index)
integer        :: index
character(len=*), intent(in)           :: list_name !< name of a field that the user wishes to copy
character(len=*), intent(in)           :: suffix !< suffix that will be added to list_name when
                                                 !! field is copied
logical,          intent(in), optional :: create !< flag to create new list if applicable

character(len=fm_string_len), dimension(:), allocatable    :: control
character(len=fm_string_len), dimension(:), allocatable    :: method
character(len=fm_string_len)                               :: head
character(len=fm_string_len)                               :: list_name_new
character(len=fm_string_len)                               :: tail
character(len=fm_string_len)                               :: val_str
integer                                                    :: n
integer                                                    :: num_meth
integer                                                    :: val_int
logical                                                    :: found_methods
logical                                                    :: got_value
logical                                                    :: recursive_t
logical                                                    :: success
logical                                                    :: val_logical
real(r8_kind)                                              :: val_real
type (field_def), pointer, save                            :: temp_field_p
type (field_def), pointer, save                            :: temp_list_p
integer                                                    :: out_unit

out_unit = stdout()


num_meth= 1
list_name_new = trim(list_name)//trim(suffix)
  recursive_t = .true.
!        Initialize the field manager if needed
if (.not. module_is_initialized) then
  call initialize_module_variables
endif

if (list_name .eq. ' ') then
!        If list is empty, then dump the current list
  temp_list_p => current_list_p
  success = .true.
else
!        Get a pointer to the list
  temp_list_p => find_list(list_name, current_list_p, .false.)
  if (associated(temp_list_p)) then
    success = .true.
  else
!        Error following the path
    success = .false.
  endif
endif
!        Find the list
if (success) then
  found_methods = fm_find_methods(trim(list_name), method, control)
  do n = 1, size(method)
    if (LEN_TRIM(method(n)) > 0 ) then
      index = fm_new_list(trim(list_name_new)//list_sep//method(n), create = create)
      call find_base(method(n), head, tail)
      temp_field_p => find_list(trim(list_name)//list_sep//head,temp_list_p, .false.)
      temp_field_p => find_field(tail,temp_field_p)
      select case (temp_field_p%field_type)
        case (integer_type)
          got_value = fm_get_value( trim(list_name)//list_sep//method(n), val_int)
          if ( fm_new_value( trim(list_name_new)//list_sep//method(n), val_int, &
                             create = create, append = .true.) < 0 ) &
            call mpp_error(FATAL, trim(error_header)//'Could not set the '//trim(method(n))//&
                                  ' for '//trim(list_name)//trim(suffix))

        case (logical_type)
          got_value = fm_get_value( trim(list_name)//list_sep//method(n), val_logical)
          if ( fm_new_value( trim(list_name_new)//list_sep//method(n), val_logical, &
                             create = create, append = .true.) < 0 ) &
            call mpp_error(FATAL, trim(error_header)//'Could not set the '//trim(method(n))//&
                                  ' for '//trim(list_name)//trim(suffix))

       case (real_type)
          got_value = fm_get_value( trim(list_name)//list_sep//method(n), val_real)
          if ( fm_new_value( trim(list_name_new)//list_sep//method(n), val_real, &
               create = create, append = .true.) < 0 ) &
               call mpp_error(FATAL, trim(error_header)//'Could not set the '//trim(method(n))//&
               ' for '//trim(list_name)//trim(suffix))

        case (string_type)
          got_value = fm_get_value( trim(list_name)//list_sep//method(n), val_str)
          if ( fm_new_value( trim(list_name_new)//list_sep//method(n), val_str, &
                             create = create, append = .true.) < 0 ) &
            call mpp_error(FATAL, trim(error_header)//'Could not set the '//trim(method(n))//&
                                  ' for '//trim(list_name)//trim(suffix))
        case default
      end select

    endif
  enddo
endif

end function fm_copy_list

!> This function retrieves all the methods associated with a field.
!!
!> This is different from fm_query_method in that this function gets all
!! the methods associated as opposed to 1 method.
!! @return A flag to indicate whether the function operated with (FALSE) or
!!     without (TRUE) errors.
function fm_find_methods(list_name, methods, control ) &
         result(success)
logical                                     :: success
character(len=*), intent(in)                :: list_name !< The name of a list that the user wishes to find methods for
character(len=*), intent(out), dimension(:) :: methods !< An array of the methods associated with list_name
character(len=*), intent(out), dimension(:) :: control !< An array of the parameters associated with methods

integer                         :: num_meth
logical                         :: recursive_t
type (field_def), pointer, save :: temp_list_p
integer                         :: out_unit

out_unit = stdout()
num_meth= 1
!        Check whether to do things recursively
  recursive_t = .true.

if (.not. module_is_initialized) then
  call initialize_module_variables
endif

if (list_name .eq. ' ') then
!        If list is empty, then dump the current list
  temp_list_p => current_list_p
  success = .true.
else
!        Get a pointer to the list
  temp_list_p => find_list(list_name, current_list_p, .false.)
  if (associated(temp_list_p)) then
    success = .true.
  else
!        Error following the path
    success = .false.
  endif
endif
!        Find the list
if (success) then
  success = find_method(temp_list_p, recursive_t, num_meth, methods, control)
endif

end function fm_find_methods

!> Given a field list pointer this function retrieves methods and
!! associated parameters for the field list.
!! @returns A flag to indicate whether the function operated with (FALSE) or
!!     without (TRUE) errors.
recursive function find_method(list_p, recursive, num_meth, method, control)   &
          result (success)
logical                                     :: success
type (field_def), pointer                   :: list_p !< A pointer to the field of interest
logical,          intent(in)                :: recursive !< If true, search recursively for fields
integer,          intent(inout)             :: num_meth !< The number of methods found
character(len=*), intent(out), dimension(:) :: method !< The methods associated with the field pointed to by list_p
character(len=*), intent(out), dimension(:) :: control !< The control parameters for the methods found

character(len=FMS_PATH_LEN) :: scratch
integer                         :: i
integer                         :: n
type (field_def), pointer, save :: this_field_p
integer                         :: out_unit

out_unit = stdout()
!        Check for a valid list
if (.not. associated(list_p) .or. list_p%field_type .ne. list_type) then
  success = .false.
else
!        set the default return value
  success = .true.

  this_field_p => list_p%first_field

  do while (associated(this_field_p))
    select case(this_field_p%field_type)
    case(list_type)
!        If this is a list, then this is the method name
        if ( this_field_p%length > 1) then
           do n = num_meth+1, num_meth + this_field_p%length - 1
              write (method(n),'(a,a,a,$)') trim(method(num_meth)), &
                                            trim(this_field_p%name), list_sep
           enddo
           write (method(num_meth),'(a,a,a,$)') trim(method(num_meth)), &
                                                trim(this_field_p%name), list_sep
        else
           write (method(num_meth),'(a,a,a,$)') trim(method(num_meth)), &
                                                trim(this_field_p%name), list_sep
        endif
        success = find_method(this_field_p, .true., num_meth, method, control)

    case(integer_type)
        write (scratch,*) this_field_p%i_value
        call strip_front_blanks(scratch)
        write (method(num_meth),'(a,a)') trim(method(num_meth)), &
                trim(this_field_p%name)
        write (control(num_meth),'(a)') &
                trim(scratch)
        num_meth = num_meth + 1


    case(logical_type)

        write (method(num_meth),'(a,a)') trim(method(num_meth)), &
                trim(this_field_p%name)
        write (control(num_meth),'(l1)') &
                this_field_p%l_value
        num_meth = num_meth + 1

    case(real_type)

       if(allocated(this_field_p%r_value)) write (scratch,*) this_field_p%r_value
        call strip_front_blanks(scratch)
        write (method(num_meth),'(a,a)') trim(method(num_meth)), &
                trim(this_field_p%name)
        write (control(num_meth),'(a)') &
                trim(scratch)
        num_meth = num_meth + 1


    case(string_type)
        write (method(num_meth),'(a,a)') trim(method(num_meth)), &
                trim(this_field_p%name)
        write (control(num_meth),'(a)') &
                 trim(this_field_p%s_value(1))
        do i = 2, this_field_p%max_index
          write (control(num_meth),'(a,a,$)') comma//trim(this_field_p%s_value(i))
        enddo
        num_meth = num_meth + 1


    case default
        success = .false.
        exit

    end select

    this_field_p => this_field_p%next
  enddo
endif

end function find_method

#include "field_manager_r4.fh"
#include "field_manager_r8.fh"

end module field_manager_mod
!> @}
! close documentation grouping