dump.py

import yaml


import re

try:
    from yaml import CSafeLoader as Loader, CDumper as Dumper
except ImportError:
    from yaml import SafeLoader as Loader, Dumper
from collections import OrderedDict

def construct_odict(load, node):
    omap = OrderedDict()
    yield omap
    if not isinstance(node, yaml.MappingNode):
        raise yaml.constructor.ConstructorError(
            "while constructing an ordered map",
            node.start_mark,
            "expected a map, but found %s" % node.id, node.start_mark
        )
    for key, value in node.value:
        key = load.construct_object(key)
        value = load.construct_object(value)
        omap[key] = value

Loader.add_constructor(u'tag:yaml.org,2002:map', construct_odict)
def ordered_dict_serializer(self, data):
    return self.represent_mapping('tag:yaml.org,2002:map', data.items())
Dumper.add_representer(OrderedDict, ordered_dict_serializer)

# Likewise, when we store unicode objects make sure we don't write
# them with weird YAML tags indicating the Python data type. The
# standard string type is fine. We should do this:
# Dumper.add_representer(unicode, lambda dumper, value: dumper.represent_scalar(u'tag:yaml.org,2002:str', value))
#
# However, the standard PyYAML representer for strings does something
# weird: if a value cannot be parsed as an integer quotes are omitted.
#
# This is incredibly odd when the value is an integer with a leading
# zero. These values are typically parsed as octal integers, meaning
# quotes would normally be required (that's good). But when the value
# has an '8' or '9' in it, this would make it an invalid octal number
# and so quotes would no longer be required (that's confusing).
# We will override str and unicode output to choose the quotation
# style with our own logic. (According to PyYAML, style can be one of
# the empty string, ', ", |, or >, or None to, presumably, choose
# automatically.
def our_string_representer(dumper, value):
# If it looks like an octal number, force '-quote style.
    style = None
    if re.match(r"^0\d*$", value): style = "'"
    return dumper.represent_scalar(u'tag:yaml.org,2002:str', value, style=style)
Dumper.add_representer(str, our_string_representer)
Dumper.add_representer(unicode, our_string_representer)

# Add a representer for nulls too. YAML accepts "~" for None, but the
# default output converts that to "null".
Dumper.add_representer(type(None), lambda dumper, value : \
dumper.represent_scalar(u'tag:yaml.org,2002:null', u"~"))

def dump_data(data) :
    out = open("dump.yaml", 'w')
    yaml.dump(data, out,  default_flow_style=False, allow_unicode=True, Dumper=Dumper)

def dump(legs) :    
    dump_data(legs['raw'])