nltk.parse.featurechart.FeatureTreeEdge

class documentation

class FeatureTreeEdge(TreeEdge): (source)

Constructor: FeatureTreeEdge(span, lhs, rhs, dot, bindings)

A specialized tree edge that allows shared variable bindings between nonterminals on the left-hand side and right-hand side.

Each FeatureTreeEdge contains a set of bindings, i.e., a dictionary mapping from variables to values. If the edge is not complete, then these bindings are simply stored. However, if the edge is complete, then the constructor applies these bindings to every nonterminal in the edge whose symbol implements the interface SubstituteBindingsI.

Static Method	`from_production`	No summary
Method	`__init__`	Construct a new edge. If the edge is incomplete (i.e., if `dot<len(rhs)`), then store the bindings as-is. If the edge is complete (i.e., if `dot==len(rhs)`), then apply the bindings to all nonterminals in ...
Method	`__str__`	Undocumented
Method	`bindings`	Return a copy of this edge's bindings dictionary.
Method	`move_dot_forward`	No summary
Method	`next_with_bindings`	Undocumented
Method	`variables`	No summary
Method	`_bind`	Undocumented
Instance Variable	`_bindings`	Undocumented
Instance Variable	`_comparison_key`	Undocumented

Inherited from TreeEdge:

Method	`__repr__`	Undocumented
Method	`dot`	Return this edge's dot position, which indicates how much of the hypothesized structure is consistent with the sentence. In particular, `self.rhs[:dot]` is consistent with `tokens[self.start():self.end()]`...
Method	`end`	Return the end index of this edge's span.
Method	`is_complete`	Return True if this edge's structure is fully consistent with the text.
Method	`is_incomplete`	Return True if this edge's structure is partially consistent with the text.
Method	`length`	Return the length of this edge's span.
Method	`lhs`	Return this edge's left-hand side, which specifies what kind of structure is hypothesized by this edge.
Method	`nextsym`	Return the element of this edge's right-hand side that immediately follows its dot.
Method	`rhs`	Return this edge's right-hand side, which specifies the content of the structure hypothesized by this edge.
Method	`span`	Return a tuple `(s, e)`, where `tokens[s:e]` is the portion of the sentence that is consistent with this edge's structure.
Method	`start`	Return the start index of this edge's span.
Instance Variable	`_dot`	Undocumented
Instance Variable	`_lhs`	Undocumented
Instance Variable	`_rhs`	Undocumented
Instance Variable	`_span`	Undocumented

Inherited from EdgeI (via TreeEdge):

Method	`__eq__`	Undocumented
Method	`__hash__`	Undocumented
Method	`__lt__`	Undocumented
Method	`__ne__`	Undocumented
Instance Variable	`_hash`	Undocumented

@staticmethod
def from_production(production, index): (source) ¶

overrides nltk.parse.chart.TreeEdge.from_production

Returns
TreeEdge	A new `TreeEdge` formed from the given production. The new edge's left-hand side and right-hand side will be taken from `production`; its span will be `(index,index)`; and its dot position will be `0`.

def __init__(self, span, lhs, rhs, dot=0, bindings=None): (source) ¶

overrides nltk.parse.chart.TreeEdge.__init__

Construct a new edge. If the edge is incomplete (i.e., if dot<len(rhs)), then store the bindings as-is. If the edge is complete (i.e., if dot==len(rhs)), then apply the bindings to all nonterminals in lhs and rhs, and then clear the bindings. See TreeEdge for a description of the other arguments.

def __str__(self): (source) ¶

overrides nltk.parse.chart.TreeEdge.__str__

Undocumented

def bindings(self): (source) ¶

Return a copy of this edge's bindings dictionary.

def move_dot_forward(self, new_end, bindings=None): (source) ¶

overrides nltk.parse.chart.TreeEdge.move_dot_forward

Parameters
new_end:int	The new end index.
bindings:dict	Bindings for the new edge.
Returns
FeatureTreeEdge	A new `FeatureTreeEdge` formed from this edge. The new edge's dot position is increased by `1`, and its end index will be replaced by `new_end`.

def next_with_bindings(self): (source) ¶

Undocumented

def variables(self): (source) ¶

Returns
set(Variable)	The set of variables used by this edge.

def _bind(self, nt, bindings): (source) ¶

Undocumented

_bindings = (source) ¶

Undocumented

_comparison_key = (source) ¶

overrides nltk.parse.chart.TreeEdge._comparison_key

Undocumented