yaml representer

[MatthewRalston]

The util module has a YAML representer for collections.OrderedDict that is utilized in the __init__.py to display the YAML metadata header in a convenient way when writing to disk.

This should be addressed in graph_algo by now, but I'm adding this to be sure.

[MatthewRalston]

def represent_yaml_from_collections_dot_OrderedDict(dumper, data):
    """
    Thanks to Blender and EquipDev on StackOverflow for this handy method to pass to yaml.add_representer
    https://stackoverflow.com/a/16782282

    I use this throughout the metadata representation in the bgzf specification to print out the representer, it's just awesome.

    I really like this answer. Finally got around to liking it this year, in Jan 2022 after using it for like a few years. 

    :param dumper: The OrderedDict_Representer, this faciliatates key sorting, consistent ordering of hasmap values, and can retain order during print for optimal metadata block structure.
    :type dumper: 
    :param data:
    :type data: dict
    """



import yaml

from collections import OrderedDict

def represent_ordereddict(dumper, data):
    value = []

    for item_key, item_value in data.items():
        node_key = dumper.represent_data(item_key)
        node_value = dumper.represent_data(item_value)

        value.append((node_key, node_value))

    return yaml.nodes.MappingNode(u'tag:yaml.org,2002:map', value)

yaml.add_representer(OrderedDict, represent_ordereddict)