added is_array()

doc/api.rst

@@ -64,6 +64,8 @@ Inform Utilities
 
 .. autofunction:: inform.is_iterable
 
+.. autofunction:: inform.is_array
+
 .. autofunction:: inform.is_mapping
 
 .. autofunction:: inform.is_str

doc/releases.rst

@@ -9,6 +9,8 @@ Latest development release
     | Version: 1.33
     | Released: 2024-12-11
 
+- Added :func:`is_array`.
+
 
 1.33 (2024-12-11)
 -----------------

doc/user.rst

@@ -797,17 +797,25 @@ You can specify the output stream when creating an informant. If you do not,
 then the stream uses is under the control of *Inform's* *stream_policy* 
 argument.
 
-If *stream_policy* is set to 'termination', then all messages are sent to the 
+If *stream_policy* is set to 'termination' then all messages are sent to the 
 standard output except the final termination message, which is set to standard 
 error.  This is suitable for programs whose output largely consists of status 
 messages rather than data, and so would be unlikely to be used in a pipeline. 
 
-If *stream_policy* is 'header'. then all messages with headers (those messages 
+If *stream_policy* is 'header' then all messages with headers (those messages 
 produced from informants with *severity*) are sent to the standard error stream 
 and all other messages are sent to the standard output. This is more suitable 
 for programs whose output largely consists of data and so would likely be used 
 in a pipeline.
 
+If *stream_policy* is 'errors' then all error messages are sent to the standard 
+error stream and all other messages are sent to the standard output.  This is 
+also commonly used for programs that act s filters.
+
+If *stream_policy* is 'all' stderr is used for all informants that do not 
+explicitly set their stream.  By default, no informants explicitly set their 
+stream, but your can create new informants and explicitly set the stream.
+
 It is also possible for *stream_policy* to be a function that takes three 
 arguments, the informant and the standard output and error streams. It should 
 return the desired stream.
@@ -1534,6 +1542,37 @@ is_iterable
     True
 
 
+.. _is_array desc:
+
+is_array
+""""""""
+
+.. py:function:: is_array(obj)
+   :noindex:
+
+:func:`is_array` returns *True* if its argument is a list or a tuple.  This 
+includes other list-like objects.
+
+.. code-block:: python
+
+    >>> from inform import is_array
+
+    >>> is_array('')  # string
+    False
+
+    >>> is_array([])  # list
+    True
+
+    >>> is_array(())  # tuple
+    True
+
+    >>> is_array({})  # dictionary
+    False
+
+    >>> is_array(set())  # set
+    False
+
+
 .. _is_mapping desc:
 
 is_mapping
@@ -1542,8 +1581,8 @@ is_mapping
 .. py:function:: is_mapping(obj)
    :noindex:
 
-:func:`is_collection` returns *True* if its argument is a mapping.  This 
-includes dictionary and other dictionary-like objects.
+:func:`is_mapping` returns *True* if its argument is a mapping.  This includes 
+dictionary and other dictionary-like objects.
 
 .. code-block:: python
 

inform/__init__.py

@@ -1,6 +1,6 @@
 from .inform import (
     # inform utility functions and classes
-    cull, indent, is_collection, is_iterable, is_mapping, is_str, join,
+    cull, indent, is_collection, is_iterable, is_array, is_mapping, is_str, join,
     Color, Info, LoggingCache,
 
     # user utility functions and classes

inform/inform.py

@@ -227,9 +227,41 @@ def is_collection(obj):
         >>> is_collection({})  # dictionary
         True
 
+        >>> is_collection(set())  # set
+        True
+
     """
     return is_iterable(obj) and not is_str(obj)
 
+# is_array {{{2
+def is_array(obj):
+    """Identifies objects that are is_array (tuples and arrays).
+
+    Returns *True* if argument is a sequence (tuple or list).
+
+    **Example**::
+
+        >>> from inform import is_array
+        >>> is_array('')  # string
+        False
+
+        >>> is_array([])  # list
+        True
+
+        >>> is_array(())  # tuple
+        True
+
+        >>> is_array({})  # dictionary
+        False
+
+        >>> is_array(set())  # set
+        False
+
+    """
+    from collections.abc import Sequence
+    return isinstance(obj, Sequence) and not is_str(obj)
+
+
 # is_mapping {{{2
 def is_mapping(obj):
     """Identifies objects that are mappings (are dictionary like).

inform/inform.pyi

@@ -23,6 +23,7 @@ def is_str(arg: Any) -> bool: ...
 def is_iterable(obj: Any) -> bool: ...
 def is_collection(obj: Any) -> bool: ...
 def is_mapping(obj: Any) -> bool: ...
+def is_array(obj: Any) -> bool: ...
 
 class Color:
     enable: bool

tests/test_utilities.py

@@ -3,10 +3,10 @@
 from inform import (
     Color, Error, Info, LoggingCache, columns, conjoin, did_you_mean, comment,
     cull, dedent, display, done, error, fatal, fmt, full_stop, indent, Inform,
-    is_collection, is_iterable, is_mapping, is_str, join, get_prog_name,
-    get_informer, narrate, os_error, output, plural, render, terminate,
-    title_case, tree, truth, warn, ddd, ppp, sss, vvv, ProgressBar, parse_range,
-    format_range
+    is_collection, is_iterable, is_mapping, is_array, is_str, join,
+    get_prog_name, get_informer, narrate, os_error, output, plural, render,
+    terminate, title_case, tree, truth, warn, ddd, ppp, sss, vvv, ProgressBar,
+    parse_range, format_range
 )
 from textwrap import dedent as tw_dedent
 import sys
@@ -795,20 +795,31 @@ def test_is_iterable():
     assert is_iterable([]) == True
     assert is_iterable(()) == True
     assert is_iterable({}) == True
+    assert is_iterable(set()) == True
 
 def test_is_collection():
     assert is_collection(0) == False
     assert is_collection('') == False
     assert is_collection([]) == True
     assert is_collection(()) == True
     assert is_collection({}) == True
+    assert is_collection(set()) == True
 
 def test_is_mapping():
     assert is_mapping(0) == False
     assert is_mapping('') == False
     assert is_mapping([]) == False
     assert is_mapping(()) == False
     assert is_mapping({}) == True
+    assert is_mapping(set()) == False
+
+def test_is_array():
+    assert is_array(0) == False
+    assert is_array('') == False
+    assert is_array([]) == True
+    assert is_array(()) == True
+    assert is_array({}) == False
+    assert is_array(set()) == False
 
 def test_color():
     assert Color('white', scheme='dark')('') == ''

tests/test_zdoctests.py

@@ -23,7 +23,7 @@ def test_inform():
         return
 
     rv = doctest.testfile('../inform/inform.py', optionflags=doctest.ELLIPSIS)
-    assert rv.attempted == 173
+    assert rv.attempted == 181
     assert rv.failed == 0
 
 def test_manual():