class graf.FeatureStructure(type_var=None, items=None)[source]

A dict of key -> feature, where feature is either a string or another FeatureStructure. A FeatureStructure may also have a type. When key is a tuple of names, or a string of names joined by ‘/’, it is interpreted as the path to a nested feature structure. Additionally, a FeatureStructure defines the operations ‘subsumes’ and ‘unify’.

__init__(type_var=None, items=None)[source]

Constructor for C{FeatureStructure}.

Parameters:type – C{str}

Returns the value corresponding to key if it is a FeatureStructure, and otherwise throws a ValueError


Returns the value corresponding to key but throws a ValueError if it is a FeatureStructure