You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
74 lines
2.1 KiB
74 lines
2.1 KiB
5 years ago
|
package com.fr.third.antlr;
|
||
|
|
|
||
|
|
/* ANTLR Translator Generator
|
||
|
|
* Project led by Terence Parr at http://www.cs.usfca.edu
|
||
|
|
* Software rights: http://www.antlr.org/license.html
|
||
|
|
*
|
||
|
|
* $Id: //depot/code/org.antlr/release/antlr-2.7.7/antlr/Alternative.java#2 $
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
/** Intermediate data class holds information about an alternative */
|
||
|
|
class Alternative {
|
||
|
|
// Tracking alternative linked list
|
||
|
|
AlternativeElement head; // head of alt element list
|
||
|
|
AlternativeElement tail; // last element added
|
||
|
|
|
||
|
|
// Syntactic predicate block if non-null
|
||
|
|
protected SynPredBlock synPred;
|
||
|
|
// Semantic predicate action if non-null
|
||
|
|
protected String semPred;
|
||
|
|
// Exception specification if non-null
|
||
|
|
protected ExceptionSpec exceptionSpec;
|
||
|
|
// Init action if non-null;
|
||
|
|
protected Lookahead[] cache; // lookahead for alt. Filled in by
|
||
|
|
// deterministic() only!!!!!!! Used for
|
||
|
|
// code gen after calls to deterministic()
|
||
|
|
// and used by deterministic for (...)*, (..)+,
|
||
|
|
// and (..)? blocks. 1..k
|
||
|
|
protected int lookaheadDepth; // each alt has different look depth possibly.
|
||
|
|
// depth can be NONDETERMINISTIC too.
|
||
|
|
// 0..n-1
|
||
|
|
// If non-null, Tree specification ala -> A B C (not implemented)
|
||
|
|
protected Token treeSpecifier = null;
|
||
|
|
// True of AST generation is on for this alt
|
||
|
|
private boolean doAutoGen;
|
||
|
|
|
||
|
|
|
||
|
|
public Alternative() {
|
||
|
|
}
|
||
|
|
|
||
|
|
public Alternative(AlternativeElement firstElement) {
|
||
|
|
addElement(firstElement);
|
||
|
|
}
|
||
|
|
|
||
|
|
public void addElement(AlternativeElement e) {
|
||
|
|
// Link the element into the list
|
||
|
|
if (head == null) {
|
||
|
|
head = tail = e;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
tail.next = e;
|
||
|
|
tail = e;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
public boolean atStart() {
|
||
|
|
return head == null;
|
||
|
|
}
|
||
|
|
|
||
|
|
public boolean getAutoGen() {
|
||
|
|
// Don't build an AST if there is a tree-rewrite-specifier
|
||
|
|
return doAutoGen && treeSpecifier == null;
|
||
|
|
}
|
||
|
|
|
||
|
|
public Token getTreeSpecifier() {
|
||
|
|
return treeSpecifier;
|
||
|
|
}
|
||
|
|
|
||
|
|
public void setAutoGen(boolean doAutoGen_) {
|
||
|
|
doAutoGen = doAutoGen_;
|
||
|
|
}
|
||
|
|
}
|