aima.core.nlp.parsing.grammars

Class ProbContextFreeGrammar

java.lang.Object

aima.core.nlp.parsing.grammars.ProbUnrestrictedGrammar

aima.core.nlp.parsing.grammars.ProbContextSensitiveGrammar

aima.core.nlp.parsing.grammars.ProbContextFreeGrammar

All Implemented Interfaces:

ProbabilisticGrammar

Direct Known Subclasses:

ProbCNFGrammar

public class ProbContextFreeGrammar
extends ProbContextSensitiveGrammar
implements ProbabilisticGrammar

Field Summary

Fields inherited from class aima.core.nlp.parsing.grammars.ProbUnrestrictedGrammar

CNFGRAMMAR, CONTEXT_FREE, CONTEXT_SENSITIVE, PROB_CONTEXT_FREE, REGULAR, rules, terminals, type, UNRESTRICTED, vars

Constructor Summary

Constructors

Constructor and Description
ProbContextFreeGrammar()

Method Summary

Modifier and Type	Method and Description
boolean	addRule(Rule r) Add a rule to the grammar's rule list if it passes both the restrictions of the parent grammars (unrestricted and context-sens) and this grammar's restrictions.
boolean	addRules(java.util.List<Rule> ruleList) Add a ruleList as the grammar's rule list if all rules in it pass both the restrictions of the parent grammars (unrestricted and context-sens) and this grammar's restrictions.
boolean	leftDerivesRight(java.util.ArrayList<java.lang.String> lhs, java.util.ArrayList<java.lang.String> rhs) Test whether LHS -> RHS is a rule in the grammar.
boolean	validRule(Rule r) For a grammar rule to be valid in a context-free grammar, all the restrictions of the parent grammars must hold, and the restriction of the context-free grammar must hold.

Methods inherited from class aima.core.nlp.parsing.grammars.ProbContextSensitiveGrammar

addRules

Methods inherited from class aima.core.nlp.parsing.grammars.ProbUnrestrictedGrammar

isTerminal, isVariable, toString, updateVarsAndTerminals, updateVarsAndTerminals, validateRuleProbabilities

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface aima.core.nlp.parsing.grammars.ProbabilisticGrammar

updateVarsAndTerminals, updateVarsAndTerminals, validateRuleProbabilities

Constructor Detail

ProbContextFreeGrammar

public ProbContextFreeGrammar()

Method Detail

addRules

public boolean addRules(java.util.List<Rule> ruleList)

Add a ruleList as the grammar's rule list if all rules in it pass both the restrictions of the parent grammars (unrestricted and context-sens) and this grammar's restrictions.

Specified by:

addRules in interface ProbabilisticGrammar

Overrides:

addRules in class ProbUnrestrictedGrammar

Returns:

true if rules are valid and incorporated into the grammar. false, otherwise

addRule

public boolean addRule(Rule r)

Add a rule to the grammar's rule list if it passes both the restrictions of the parent grammars (unrestricted and context-sens) and this grammar's restrictions.

Specified by:

addRule in interface ProbabilisticGrammar

Overrides:

addRule in class ProbContextSensitiveGrammar

Returns:

true if rule is incorporated. false, otherwise

validRule

public boolean validRule(Rule r)

For a grammar rule to be valid in a context-free grammar, all the restrictions of the parent grammars must hold, and the restriction of the context-free grammar must hold. The restriction is that the lhs must consist of a single non-terminal (variable). There are no restrictions on the rhs

Specified by:

validRule in interface ProbabilisticGrammar

Overrides:

validRule in class ProbContextSensitiveGrammar

Parameters:

r - ( a rule )

Returns:

true, if rule has valid form. false, otherwise

leftDerivesRight

public boolean leftDerivesRight(java.util.ArrayList<java.lang.String> lhs,
                                java.util.ArrayList<java.lang.String> rhs)

Test whether LHS -> RHS is a rule in the grammar. Note: it must be a DIRECT derivation

Parameters:

lhs -

rhs -

Returns: