ANTLR 3.5.3 · org.antlr.analysis.NFAConfiguration

Field Summary

Modifier and Type	Field and Description
public int	alt What alt is predicted by this configuration
public NFAContext	context What is the stack of rule invocations that got us to state?
protected int	numberEpsilonTransitionsEmanatingFromState Lots of NFA states have only epsilon edges (1 or 2).
protected boolean	resolved Indicate that this configuration has been resolved and no further DFA processing should occur with it.
protected boolean	resolveWithPredicate This bit is used to indicate a semantic predicate will be used to resolve the conflict.
public SemanticContext	semanticContext The set of semantic predicates associated with this NFA configuration.
protected boolean	singleAtomTransitionEmanating Indicates that the NFA state associated with this configuration has exactly one transition and it's an atom (not epsilon etc...).
public int	state The NFA state associated with this configuration

Constructor Summary

Access	Constructor and Description
public	NFAConfiguration(int state, int alt, NFAContext context, SemanticContext semanticContext)

Method Summary

Modifier and Type	Method and Description
public boolean	equals(Object the reference object with which to compare. o) Overrides java.lang.Object.equals. An NFA configuration is equal to another if both have the same state, the predict the same alternative, and syntactic/semantic contexts are the same.
public int	hashCode() Overrides java.lang.Object.hashCode. Returns a hash code value for this object.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
public String	toString(boolean showAlt)

Inherited from java.lang.Object:: clone finalize getClass notify notifyAll wait wait wait

Field Detail

alt	back to summary
public int alt What alt is predicted by this configuration

context	back to summary
public NFAContext context What is the stack of rule invocations that got us to state?

numberEpsilonTransitionsEmanatingFromState	back to summary
protected int numberEpsilonTransitionsEmanatingFromState Lots of NFA states have only epsilon edges (1 or 2). We can safely consider only n>0 during closure.

resolved	back to summary
protected boolean resolved Indicate that this configuration has been resolved and no further DFA processing should occur with it. Essentially, this is used as an "ignore" bit so that upon a set of nondeterministic configurations such as (s\|2) and (s\|3), I can set (s\|3) to resolved=true (and any other configuration associated with alt 3).

resolveWithPredicate	back to summary
protected boolean resolveWithPredicate This bit is used to indicate a semantic predicate will be used to resolve the conflict. Method DFA.findNewDFAStatesAndAddDFATransitions will add edges for the predicates after it performs the reach operation. The nondeterminism resolver sets this when it finds a set of nondeterministic configurations (as it does for "resolved" field) that have enough predicates to resolve the conflit.

resolveWithPredicate

back to summary

protected boolean resolveWithPredicate

This bit is used to indicate a semantic predicate will be used to resolve the conflict. Method DFA.findNewDFAStatesAndAddDFATransitions will add edges for the predicates after it performs the reach operation. The nondeterminism resolver sets this when it finds a set of nondeterministic configurations (as it does for "resolved" field) that have enough predicates to resolve the conflit.

semanticContext	back to summary
public SemanticContext semanticContext The set of semantic predicates associated with this NFA configuration. The predicates were found on the way to the associated NFA state in this syntactic context. Set<AST>: track nodes in grammar containing the predicate for error messages and such (nice to know where the predicate came from in case of duplicates etc...). By using a set, the equals() method will correctly show {pred1,pred2} as equals() to {pred2,pred1}.

semanticContext

back to summary

public SemanticContext semanticContext

The set of semantic predicates associated with this NFA configuration. The predicates were found on the way to the associated NFA state in this syntactic context. Set<AST>: track nodes in grammar containing the predicate for error messages and such (nice to know where the predicate came from in case of duplicates etc...). By using a set, the equals() method will correctly show {pred1,pred2} as equals() to {pred2,pred1}.

singleAtomTransitionEmanating	back to summary
protected boolean singleAtomTransitionEmanating Indicates that the NFA state associated with this configuration has exactly one transition and it's an atom (not epsilon etc...).

state	back to summary
public int state The NFA state associated with this configuration

Constructor Detail

NFAConfiguration	back to summary
public NFAConfiguration(int state, int alt, NFAContext context, SemanticContext semanticContext)

Method Detail

equals back to summary

equals	back to summary
public boolean equals(Object o) Overrides java.lang.Object.equals. An NFA configuration is equal to another if both have the same state, the predict the same alternative, and syntactic/semantic contexts are the same. I don't think the state\|alt\|ctx could be the same and have two different semantic contexts, but might as well define equals to be everything. Parameters o:Object Doc from java.lang.Object.equals. the reference object with which to compare. Returns:boolean Doc from java.lang.Object.equals. `true` if this object is the same as the obj argument; `false` otherwise. Annotations @Override

public boolean equals(Object o)

Overrides java.lang.Object.equals.

An NFA configuration is equal to another if both have the same state, the predict the same alternative, and syntactic/semantic contexts are the same. I don't think the state|alt|ctx could be the same and have two different semantic contexts, but might as well define equals to be everything.

Parameters

o:Object

Doc from java.lang.Object.equals.

the reference object with which to compare.

Returns:boolean

Doc from java.lang.Object.equals.

true if this object is the same as the obj argument; false otherwise.

Annotations

@Override

hashCode back to summary

hashCode	back to summary
public int hashCode() Overrides java.lang.Object.hashCode. Doc from java.lang.Object.hashCode. Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by `java.util.HashMap`. The general contract of `hashCode` is: Whenever it is invoked on the same object more than once during an execution of a Java application, the `hashCode` method must consistently return the same integer, provided no information used in `equals` comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application. If two objects are equal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce the same integer result. It is not required that if two objects are unequal according to the `equals` method, then calling the `hashCode` method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables. Returns:int a hash code value for this object Annotations @Override

public int hashCode()

Overrides java.lang.Object.hashCode.

Doc from java.lang.Object.hashCode.

Returns a hash code value for this object. This method is supported for the benefit of hash tables such as those provided by java.util.HashMap.

The general contract of hashCode is:

Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
If two objects are equal according to the equals method, then calling the hashCode method on each of the two objects must produce the same integer result.
It is not required that if two objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

Returns:int

a hash code value for this object

Annotations

@Override

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object

Annotations

@Override

toString	back to summary
public String toString(boolean showAlt)

public Class NFAConfiguration

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail