nltk.parse.featurechart

Module featurechart

Extension of chart parsing implementation to handle grammars with feature structures as nodes.

Classes

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

FeatureFundamentalRule
A specialized version of the fundamental rule that operates on nonterminals whose symbols are FeatStructNonterminals.

FeatureTopDownExpandRule
A specialized version of the top down expand rule that operates on nonterminals whose symbols are FeatStructNonterminals.

FeatureCompleterRule
A specialized version of the completer rule that operates on nonterminals whose symbols are FeatStructNonterminals.

FeatureScannerRule

FeaturePredictorRule

EarleyChartParser
A chart parser implementing the Earley parsing algorithm:

FeatureEarleyChartParser
A chart parser implementing the Earley parsing algorithm, allowing nonterminals that have features (known as FeatStructNonterminals).

InstantiateVarsChart
A specialized chart that 'instantiates' variables whose names start with '@', by replacing them with unique new variables.

Functions

[hide private]

load_earley(filename, trace=0, cache=False, verbose=False, chart_class=<class 'nltk.parse.chart.Chart'>)
Load a grammar from a file, and build an Earley feature parser based on that grammar.

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demo()

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run_profile()

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Function Details

[hide private]

load_earley(filename, trace=0, cache=False, verbose=False, chart_class=<class 'nltk.parse.chart.Chart'>)

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Load a grammar from a file, and build an Earley feature parser based on that grammar.

You can optionally specify a tracing level, for how much output you want to see:

0: No output. 1: Show edges from scanner and completer rules (not predictor). 2 (default): Show all edges as they are added to the chart. 3: Show all edges, plus the results of successful unifications. 4: Show all edges, plus the results of all attempted unifications. 5: Show all edges, plus the results of all attempted unifications, including those with cached results.

If verbose is set to True, then more diagnostic information about grammar-loading is displayed.