Class ChartRuleI

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object --+
         |
        ChartRuleI

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.

Instance Methods

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list of EdgeI

apply(self, chart, grammar, *edges)
Add the edges licensed by this rule and the given edges to the chart.

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iter of EdgeI

apply_iter(self, chart, grammar, *edges)
Returns: A generator that will add edges licensed by this rule and the given edges to the chart, one at a time.

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list of EdgeI

apply_everywhere(self, chart, grammar)
Add all the edges licensed by this rule and the edges in the chart to the chart.

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iter of EdgeI

apply_everywhere_iter(self, chart, grammar)
Returns: A generator that will add all edges licensed by this rule, given the edges that are currently in the chart, one at a time.

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Inherited from object: __delattr__, __getattribute__, __hash__, __init__, __new__, __reduce__, __reduce_ex__, __repr__, __setattr__, __str__

Class Variables

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int NUM_EDGES
The number of existing edges that this rule uses to license new edges.

Properties

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Inherited from object: __class__

Method Details

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apply(self, chart, grammar, *edges)

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Add the edges licensed by this rule and the given edges to the chart.

Parameters:

edges (list of 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: list of EdgeI

A list of the edges that were added.

apply_iter(self, chart, grammar, *edges)

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Parameters:

edges (list of 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 of EdgeI

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.

apply_everywhere(self, chart, grammar)

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Add all the edges licensed by this rule and the edges in the chart to the chart.

Returns: list of EdgeI: A list of the edges that were added.

apply_everywhere_iter(self, chart, grammar)

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Returns: iter of EdgeI: 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 Details

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NUM_EDGES

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

Type:: int