nltk.parse.chart.ChartRuleI

class documentation

class ChartRuleI(object): (source)

Known subclasses: nltk.parse.chart.AbstractChartRule

A rule that specifies what new edges are licensed by any given set of existing edges. Each chart rule expects a fixed number of edges, as indicated by the class variable NUM_EDGES. In particular:

A chart rule with NUM_EDGES=0 specifies what new edges are licensed, regardless of existing edges.
A chart rule with NUM_EDGES=1 specifies what new edges are licensed by a single existing edge.
A chart rule with NUM_EDGES=2 specifies what new edges are licensed by a pair of existing edges.

Method	`apply`	Return a generator that will add edges licensed by this rule and the given edges to the chart, one at a time. Each time the generator is resumed, it will either add a new edge and yield that edge; or return.
Method	`apply_everywhere`	Return a generator that will add all edges licensed by this rule, given the edges that are currently in the chart, one at a time. Each time the generator is resumed, it will either add a new edge and yield that edge; or return.
Class Variable	`NUM_EDGES`	The number of existing edges that this rule uses to license new edges. Typically, this number ranges from zero to two.

def apply(self, chart, grammar, *edges): (source) ¶

overridden in nltk.parse.chart.AbstractChartRule

Return a generator that will add edges licensed by this rule and the given edges to the chart, one at a time. Each time the generator is resumed, it will either add a new edge and yield that edge; or return.

Parameters
chart	Undocumented
grammar	Undocumented
*edges:list(EdgeI)	A set of existing edges. The number of edges that should be passed to `apply()` is specified by the `NUM_EDGES` class variable.
Returns
iter(EdgeI)	Undocumented

def apply_everywhere(self, chart, grammar): (source) ¶

overridden in nltk.parse.chart.AbstractChartRule

Return a generator that will add all edges licensed by this rule, given the edges that are currently in the chart, one at a time. Each time the generator is resumed, it will either add a new edge and yield that edge; or return.

Returns
iter(EdgeI)	Undocumented

NUM_EDGES: int = (source) ¶

overridden in nltk.parse.chart.BottomUpPredictRule, nltk.parse.chart.EmptyPredictRule, nltk.parse.chart.FundamentalRule, nltk.parse.chart.LeafInitRule, nltk.parse.chart.TopDownInitRule, nltk.parse.chart.TopDownPredictRule, nltk.parse.pchart.ProbabilisticBottomUpInitRule, nltk.parse.pchart.ProbabilisticBottomUpPredictRule, nltk.parse.pchart.ProbabilisticFundamentalRule, nltk.parse.pchart.SingleEdgeProbabilisticFundamentalRule

The number of existing edges that this rule uses to license new edges. Typically, this number ranges from zero to two.