nltk.parse.featurechart.InstantiateVarsChart

class documentation

class InstantiateVarsChart(FeatureChart): (source)

Constructor: InstantiateVarsChart(tokens)

A specialized chart that 'instantiates' variables whose names start with '@', by replacing them with unique new variables. In particular, whenever a complete edge is added to the chart, any variables in the edge's lhs whose names start with '@' will be replaced by unique new ``Variable``s.

Method	`__init__`	Construct a new chart. The chart is initialized with the leaf edges corresponding to the terminal leaves.
Method	`initialize`	Clear the chart.
Method	`insert`	Add a new edge to the chart, and return True if this operation modified the chart. In particular, return true iff the chart did not already contain `edge`, or if it did not already associate `child_pointer_lists`...
Method	`inst_vars`	Undocumented
Method	`instantiate_edge`	If the edge is a `FeatureTreeEdge`, and it is complete, then instantiate all variables whose names start with '@', by replacing them with unique new variables.
Instance Variable	`_instantiated`	Undocumented

Inherited from FeatureChart:

Method	`parses`	Return an iterator of the complete tree structures that span the entire chart, and whose root node is `root`.
Method	`select`	Returns an iterator over the edges in this chart. See `Chart.select` for more information about the `restrictions` on the edges.
Method	`_add_index`	A helper function for `select`, which creates a new index for a given set of attributes (aka restriction keys).
Method	`_get_type_if_possible`	Helper function which returns the `TYPE` feature of the `item`, if it exists, otherwise it returns the `item` itself
Method	`_register_with_indexes`	A helper function for `insert`, which registers the new edge with all existing indexes.

Inherited from Chart (via FeatureChart):

Method	`child_pointer_lists`	Return the set of child pointer lists for the given edge. Each child pointer list is a list of edges that have been used to form this edge.
Method	`dot_digraph`	Undocumented
Method	`edges`	Return a list of all edges in this chart. New edges that are added to the chart after the call to edges() will not be contained in this list.
Method	`insert_with_backpointer`	Add a new edge to the chart, using a pointer to the previous edge.
Method	`iteredges`	Return an iterator over the edges in this chart. It is not guaranteed that new edges which are added to the chart before the iterator is exhausted will also be generated.
Method	`leaf`	Return the leaf value of the word at the given index.
Method	`leaves`	Return a list of the leaf values of each word in the chart's sentence.
Method	`num_edges`	Return the number of edges contained in this chart.
Method	`num_leaves`	Return the number of words in this chart's sentence.
Method	`pretty_format`	Return a pretty-printed string representation of this chart.
Method	`pretty_format_edge`	Return a pretty-printed string representation of a given edge in this chart.
Method	`pretty_format_leaves`	Return a pretty-printed string representation of this chart's leaves. This string can be used as a header for calls to `pretty_format_edge`.
Method	`trees`	Return an iterator of the tree structures that are associated with `edge`.
Method	`_append_edge`	Undocumented
Method	`_trees`	A helper function for `trees`.
Instance Variable	`_edge_to_cpls`	A dictionary mapping each edge to a set of child pointer lists that are associated with that edge.
Instance Variable	`_edges`	A list of the edges in the chart
Instance Variable	`_indexes`	A dictionary mapping tuples of edge attributes to indices, where each index maps the corresponding edge attribute values to lists of edges.
Instance Variable	`_num_leaves`	The number of tokens.
Instance Variable	`_tokens`	The sentence that the chart covers.

def __init__(self, tokens): (source) ¶

overrides nltk.parse.chart.Chart.__init__

Construct a new chart. The chart is initialized with the leaf edges corresponding to the terminal leaves.

Parameters
tokens:list	The sentence that this chart will be used to parse.

def initialize(self): (source) ¶

overrides nltk.parse.chart.Chart.initialize

Clear the chart.

def insert(self, edge, child_pointer_list): (source) ¶

overrides nltk.parse.chart.Chart.insert

Add a new edge to the chart, and return True if this operation modified the chart. In particular, return true iff the chart did not already contain edge, or if it did not already associate child_pointer_lists with edge.

Parameters
edge:EdgeI	The new edge
child_pointer_list	Undocumented
*child_pointer_lists:sequence of tuple(EdgeI)	A sequence of lists of the edges that were used to form this edge. This list is used to reconstruct the trees (or partial trees) that are associated with `edge`.
Returns
bool	Undocumented

def inst_vars(self, edge): (source) ¶

Undocumented

def instantiate_edge(self, edge): (source) ¶

If the edge is a FeatureTreeEdge, and it is complete, then instantiate all variables whose names start with '@', by replacing them with unique new variables.

Note that instantiation is done in-place, since the parsing algorithms might already hold a reference to the edge for future use.

_instantiated = (source) ¶

Undocumented