com.oracle.truffle.regex.tregex.parser.ast.visitors

Class NFATraversalRegexASTVisitor

java.lang.Object

com.oracle.truffle.regex.tregex.parser.ast.visitors.NFATraversalRegexASTVisitor

Direct Known Subclasses:

ASTStepVisitor, MarkLookBehindEntriesVisitor

public abstract class NFATraversalRegexASTVisitor
extends Object

Special AST visitor that will find all immediate successors of a given Term when the AST is seen as a NFA, in priority order. A successor can either be a CharacterClass or a MatchFound node.

 
 Examples:

 Successors of "b" in (a|b)c:
 1.: "c"

 Successors of "b" in (a|b)*c:
 1.: "a"
 2.: "b"
 3.: "c"
 
 

For every successor, the visitor will find the full path of AST nodes that have been traversed from the initial node to the successor node, where Group nodes are treated specially: The path will contain separate entries for entering and leaving a Group, and a special pass-through node for empty sequences of Groups marked with Group.isExpandedQuantifier(). Furthermore, the visitor will not descend into lookaround assertions, it will jump over them and just add their corresponding LookAheadAssertion or LookBehindAssertion node to the path. This visitor is not thread-safe, since it uses the methods of RegexASTVisitorIterable for traversing groups.

 
 Examples with full path information:

 Successors of "b" in (a|b)c:
 1.: [leave group 1], [CharClass c]

 Successors of "b" in (a|b)*c:
 1.: [leave group 1], [enter group 1], [CharClass a]
 2.: [leave group 1], [enter group 1], [CharClass b]
 3.: [leave group 1], [CharClass c]
 
 

Field Summary

Fields

Modifier and Type	Field and Description
protected RegexAST	ast

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	NFATraversalRegexASTVisitor(RegexAST ast)

Method Summary

Modifier and Type	Method and Description
boolean	canTraverseCaret()
protected boolean	dollarsOnPath()
protected abstract void	enterLookAhead(LookAheadAssertion assertion)
protected GroupBoundaries	getGroupBoundaries()
protected PositionAssertion	getLastDollarOnPath()
Set<LookBehindAssertion>	getTraversableLookBehindAssertions()
protected abstract void	leaveLookAhead(LookAheadAssertion assertion)
protected void	run(Term runRoot)
void	setCanTraverseCaret(boolean canTraverseCaret)
void	setReverse(boolean reverse)
void	setTraversableLookBehindAssertions(Set<LookBehindAssertion> traversableLookBehindAssertions)
protected abstract void	visit(RegexASTNode target) Visit the next successor found.

Methods inherited from class java.lang.Object

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

Field Detail

ast

protected final RegexAST ast

Constructor Detail

NFATraversalRegexASTVisitor

protected NFATraversalRegexASTVisitor(RegexAST ast)

Method Detail

getTraversableLookBehindAssertions

public Set<LookBehindAssertion> getTraversableLookBehindAssertions()

setTraversableLookBehindAssertions

public void setTraversableLookBehindAssertions(Set<LookBehindAssertion> traversableLookBehindAssertions)

canTraverseCaret

public boolean canTraverseCaret()

setCanTraverseCaret

public void setCanTraverseCaret(boolean canTraverseCaret)

setReverse

public void setReverse(boolean reverse)

run

protected void run(Term runRoot)

visit

protected abstract void visit(RegexASTNode target)

Visit the next successor found.

enterLookAhead

protected abstract void enterLookAhead(LookAheadAssertion assertion)

leaveLookAhead

protected abstract void leaveLookAhead(LookAheadAssertion assertion)

dollarsOnPath

protected boolean dollarsOnPath()

getLastDollarOnPath

protected PositionAssertion getLastDollarOnPath()

getGroupBoundaries

protected GroupBoundaries getGroupBoundaries()