Package jflex.core

Class NFA

java.lang.Object

jflex.core.NFA

public final class NFA
extends Object

Non-deterministic finite automata representation in JFlex.

Contains algorithms RegExp → NFA.

Version:

JFlex 1.8.1

Author:

Gerwin Klein

Constructor Summary

Constructors

Constructor	Description
NFA(int numInput, int estSize)	Constructor for NFA.
NFA(int numInput, LexScan scanner, RegExps regExps, Macros macros, CharClasses classes)	Construct new NFA.

Method Summary

Modifier and Type	Method	Description
void	addEpsilonTransition(int start, int dest)
void	addRegExp(int regExpNum)	Add a regexp to this NFA.
void	addStandaloneRule()	Add a standalone rule that has minimum priority, fires a transition on all single input characters and has a "print yytext" action.
void	addTransition(int start, int input, int dest)
boolean	containsFinal(StateSet set)	Returns true, iff the specified set of states contains a final state.
String	dotFormat()
void	dumpTable()
StateSet	epsilon(int i)
void	epsilonFill()
Action	getAction(StateSet set)	Returns the action with highest priority in the specified set of states.
IntPair	insertNFA(RegExp regExp)	Constructs an NFA for regExp such that the NFA has
int	numEntryStates()
int	numInput()
int	numLexStates()
int	numStates()
StateSet	reachableStates(int currentState, int nextChar)	Returns the set of states that can be reached from currentState with an input nextChar.
StateSetEnumerator	states()
StateSet	tempStateSet()
String	toString()
void	writeDot(File file)

Methods inherited from class java.lang.Object

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

Constructor Detail

NFA

public NFA(int numInput,
           int estSize)

Constructor for NFA.

NFA

public NFA(int numInput,
           LexScan scanner,
           RegExps regExps,
           Macros macros,
           CharClasses classes)

Construct new NFA.

Assumes that lookahead cases and numbers are already resolved in RegExps.

Parameters:

numInput - a int.

scanner - a LexScan object.

regExps - a RegExps object.

macros - a Macros object.

classes - a CharClasses object.

See Also:

RegExps.checkLookAheads()

Method Detail

epsilon

public StateSet epsilon(int i)

numEntryStates

public int numEntryStates()

numInput

public int numInput()

numLexStates

public int numLexStates()

numStates

public int numStates()

reachableStates

public StateSet reachableStates(int currentState,
                                int nextChar)

Returns the set of states that can be reached from currentState with an input nextChar.

states

public StateSetEnumerator states()

tempStateSet

public StateSet tempStateSet()

addStandaloneRule

public void addStandaloneRule()

Add a standalone rule that has minimum priority, fires a transition on all single input characters and has a "print yytext" action.

addRegExp

public void addRegExp(int regExpNum)

Add a regexp to this NFA.

Parameters:

regExpNum - the number of the regexp to add.

addTransition

public void addTransition(int start,
                          int input,
                          int dest)

addEpsilonTransition

public void addEpsilonTransition(int start,
                                 int dest)

containsFinal

public boolean containsFinal(StateSet set)

Returns true, iff the specified set of states contains a final state.

Parameters:

set - the set of states that is tested for final states.

getAction

public Action getAction(StateSet set)

Returns the action with highest priority in the specified set of states.

Parameters:

set - the set of states for which to determine the action

epsilonFill

public void epsilonFill()

dumpTable

public void dumpTable()

toString

public String toString()

Overrides:

toString in class Object

writeDot

public void writeDot(File file)

dotFormat

public String dotFormat()

insertNFA

public IntPair insertNFA(RegExp regExp)

Constructs an NFA for regExp such that the NFA has

exactly one start state, exactly one end state, no transitions leading out of the end state no transitions leading into the start state

Parameters:

regExp - the regular expression to construct the NFA for

Returns:

a pair of integers denoting the index of start and end state of the NFA.