ANTLR 3.5.3 · org.antlr.analysis.NFAState

Field Summary

Modifier and Type	Field and Description
public GrammarAST	associatedASTNode Associate this NFAState with the corresponding GrammarAST node from which this node was created.
public static final int	BLOCK_START
public static final int	BYPASS
protected int	decisionNumber What's its decision number from 1..n?
public int	decisionStateType Subrules (...)* and (...)+ have more than one decision point in the NFA created for them.
protected String	description During debugging and for nondeterminism warnings, it's useful to know what relationship this node has to the original grammar.
public Rule	enclosingRule What rule do we live in?
public int	endOfBlockStateNumber Jean Bovet needs in the GUI to know which state pairs correspond to the start/stop of a block.
protected boolean	EOTTargetState Is this state the sole target of an EOT transition?
public Label	incidentEdgeLabel For o-A->o type NFA tranitions, record the label that leads to this state.
public static final int	LOOPBACK
public static final int	MAX_TRANSITIONS
public NFA	nfa Which NFA are we in?
pack-priv int	numTransitions How many transitions; 0, 1, or 2 transitions
public static final int	OPTIONAL_BLOCK_START
public static final int	RIGHT_EDGE_OF_BLOCK
public Transition[]	transition

Inherited from org.antlr.analysis.State:: acceptState INVALID_STATE_NUMBER stateNumber

Constructor Summary

Access	Constructor and Description
public	NFAState(NFA nfa)

Method Summary

Modifier and Type	Method and Description
public void	addTransition(Transition e) Implements abstract org.antlr.analysis.State.addTransition.
public int	getDecisionNumber()
public String	getDescription()
public int	getNumberOfTransitions() Implements abstract org.antlr.analysis.State.getNumberOfTransitions.
public boolean	isDecisionState()
public boolean	isEOTTargetState()
public void	setDecisionASTNode(GrammarAST decisionASTNode) What AST node is associated with this NFAState?
public void	setDecisionNumber(int decisionNumber)
public void	setDescription(String description)
public void	setEOTTargetState(boolean eot)
public void	setTransition0(Transition e) Used during optimization to reset a state to have the (single) transition another state has.
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
public Transition	transition(int i) Implements abstract org.antlr.analysis.State.transition.
public int	translateDisplayAltToWalkAlt(int displayAlt) The DFA decision for this NFA decision state always has an exit path for loops as n+1 for n alts in the loop.

Inherited from org.antlr.analysis.State:: isAcceptState setAcceptState

Field Detail

associatedASTNode	back to summary
public GrammarAST associatedASTNode Associate this NFAState with the corresponding GrammarAST node from which this node was created. This is useful not only for associating the eventual lookahead DFA with the associated Grammar position, but also for providing users with nondeterminism warnings. Mainly used by decision states to report line:col info. Could also be used to track line:col for elements such as token refs.

associatedASTNode

back to summary

public GrammarAST associatedASTNode

Associate this NFAState with the corresponding GrammarAST node from which this node was created. This is useful not only for associating the eventual lookahead DFA with the associated Grammar position, but also for providing users with nondeterminism warnings. Mainly used by decision states to report line:col info. Could also be used to track line:col for elements such as token refs.

BLOCK_START	back to summary
public static final int BLOCK_START

BYPASS	back to summary
public static final int BYPASS

decisionNumber	back to summary
protected int decisionNumber What's its decision number from 1..n?

decisionStateType	back to summary
public int decisionStateType Subrules (...)* and (...)+ have more than one decision point in the NFA created for them. They both have a loop-exit-or-stay-in decision node (the loop back node). They both have a normal alternative block decision node at the left edge. The (...)* is worse as it even has a bypass decision (2 alts: stay in or bypass) node at the extreme left edge. This is not how they get generated in code as a while-loop or whatever deals nicely with either. For error messages (where I need to print the nondeterministic alts) and for interpretation, I need to use the single DFA that is created (for efficiency) but interpret the results differently depending on which of the 2 or 3 decision states uses the DFA. For example, the DFA will always report alt n+1 as the exit branch for n real alts, so I need to translate that depending on the decision state. If decisionNumber>0 then this var tells you what kind of decision state it is.

decisionStateType

back to summary

public int decisionStateType

Subrules (...)* and (...)+ have more than one decision point in the NFA created for them. They both have a loop-exit-or-stay-in decision node (the loop back node). They both have a normal alternative block decision node at the left edge. The (...)* is worse as it even has a bypass decision (2 alts: stay in or bypass) node at the extreme left edge. This is not how they get generated in code as a while-loop or whatever deals nicely with either. For error messages (where I need to print the nondeterministic alts) and for interpretation, I need to use the single DFA that is created (for efficiency) but interpret the results differently depending on which of the 2 or 3 decision states uses the DFA. For example, the DFA will always report alt n+1 as the exit branch for n real alts, so I need to translate that depending on the decision state. If decisionNumber>0 then this var tells you what kind of decision state it is.

description	back to summary
protected String description During debugging and for nondeterminism warnings, it's useful to know what relationship this node has to the original grammar. For example, "start of alt 1 of rule a".

enclosingRule	back to summary
public Rule enclosingRule What rule do we live in?

endOfBlockStateNumber	back to summary
public int endOfBlockStateNumber Jean Bovet needs in the GUI to know which state pairs correspond to the start/stop of a block.

EOTTargetState	back to summary
protected boolean EOTTargetState Is this state the sole target of an EOT transition?

incidentEdgeLabel	back to summary
public Label incidentEdgeLabel For o-A->o type NFA tranitions, record the label that leads to this state. Useful for creating rich error messages when we find insufficiently (with preds) covered states.

LOOPBACK	back to summary
public static final int LOOPBACK

MAX_TRANSITIONS	back to summary
public static final int MAX_TRANSITIONS

nfa	back to summary
public NFA nfa Which NFA are we in?

numTransitions	back to summary
pack-priv int numTransitions How many transitions; 0, 1, or 2 transitions

OPTIONAL_BLOCK_START	back to summary
public static final int OPTIONAL_BLOCK_START

RIGHT_EDGE_OF_BLOCK	back to summary
public static final int RIGHT_EDGE_OF_BLOCK

transition	back to summary
public Transition[] transition

Constructor Detail

NFAState	back to summary
public NFAState(NFA nfa)

Method Detail

addTransition	back to summary
public void addTransition(Transition e) Implements abstract org.antlr.analysis.State.addTransition. Annotations @Override

addTransition

back to summary

public void addTransition(Transition e)

Implements abstract org.antlr.analysis.State.addTransition.

Annotations

@Override

getDecisionNumber	back to summary
public int getDecisionNumber()

getDescription	back to summary
public String getDescription()

getNumberOfTransitions	back to summary
public int getNumberOfTransitions() Implements abstract org.antlr.analysis.State.getNumberOfTransitions. Annotations @Override

getNumberOfTransitions

back to summary

public int getNumberOfTransitions()

Implements abstract org.antlr.analysis.State.getNumberOfTransitions.

Annotations

@Override

isDecisionState	back to summary
public boolean isDecisionState()

isEOTTargetState	back to summary
public boolean isEOTTargetState()

setDecisionASTNode	back to summary
public void setDecisionASTNode(GrammarAST decisionASTNode) What AST node is associated with this NFAState? When you set the AST node, I set the node to point back to this NFA state.

setDecisionNumber	back to summary
public void setDecisionNumber(int decisionNumber)

setDescription	back to summary
public void setDescription(String description)

setEOTTargetState	back to summary
public void setEOTTargetState(boolean eot)

setTransition0	back to summary
public void setTransition0(Transition e) Used during optimization to reset a state to have the (single) transition another state has.

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

transition	back to summary
public Transition transition(int i) Implements abstract org.antlr.analysis.State.transition. Annotations @Override

transition

back to summary

public Transition transition(int i)

Implements abstract org.antlr.analysis.State.transition.

Annotations

@Override

translateDisplayAltToWalkAlt	back to summary
public int translateDisplayAltToWalkAlt(int displayAlt) The DFA decision for this NFA decision state always has an exit path for loops as n+1 for n alts in the loop. That is really useful for displaying nondeterministic alts and so on, but for walking the NFA to get a sequence of edge labels or for actually parsing, we need to get the real alt number. The real alt number for exiting a loop is always 1 as transition 0 points at the exit branch (we compute DFAs always for loops at the loopback state). For walking/parsing the loopback state: 1 2 3 display alt (for human consumption) 2 3 1 walk alt For walking the block start: 1 2 3 display alt 1 2 3 For walking the bypass state of a (...)* loop: 1 2 3 display alt 1 1 2 all block alts map to entering loop exit means take bypass Non loop EBNF do not need to be translated; they are ignored by this method as decisionStateType==0. Return same alt if we can't translate.

translateDisplayAltToWalkAlt

back to summary

public int translateDisplayAltToWalkAlt(int displayAlt)

The DFA decision for this NFA decision state always has an exit path for loops as n+1 for n alts in the loop. That is really useful for displaying nondeterministic alts and so on, but for walking the NFA to get a sequence of edge labels or for actually parsing, we need to get the real alt number. The real alt number for exiting a loop is always 1 as transition 0 points at the exit branch (we compute DFAs always for loops at the loopback state). For walking/parsing the loopback state: 1 2 3 display alt (for human consumption) 2 3 1 walk alt For walking the block start: 1 2 3 display alt 1 2 3 For walking the bypass state of a (...)* loop: 1 2 3 display alt 1 1 2 all block alts map to entering loop exit means take bypass Non loop EBNF do not need to be translated; they are ignored by this method as decisionStateType==0. Return same alt if we can't translate.

public Class NFAState

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Field Detail

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Method Detail