Package org.antlr.v4.analysis

Class LeftRecursiveRuleTransformer

java.lang.Object

org.antlr.v4.analysis.LeftRecursiveRuleTransformer

public class LeftRecursiveRuleTransformer
extends Object

Remove left-recursive rule refs, add precedence args to recursive rule refs. Rewrite rule so we can create ATN. MODIFIES grammar AST in place.

Field Summary

Fields

Modifier and Type	Field	Description
GrammarRootAST	ast
Grammar	g
static String	PRECEDENCE_OPTION_NAME
Collection<Rule>	rules
static String	TOKENINDEX_OPTION_NAME
Tool	tool

Constructor Summary

Constructors

Constructor	Description
LeftRecursiveRuleTransformer(GrammarRootAST ast, Collection<Rule> rules, Grammar g)

Method Summary

Modifier and Type	Method	Description
RuleAST	parseArtificialRule(Grammar g, String ruleText)
void	setAltASTPointers(LeftRecursiveRule r, RuleAST t)	(RULE e int _p (returns int v) (BLOCK (ALT (BLOCK (ALT INT {$v = $INT.int;}) (ALT '(' (= x e) ')' {$v = $x.v;}) (ALT ID)) (* (BLOCK (OPTIONS ...) (ALT {7 >= $_p}? '*' (= b e) {$v = $a.v * $b.v;}) (ALT {6 >= $_p}? '+' (= b e) {$v = $a.v + $b.v;}) (ALT {3 >= $_p}? '++') (ALT {2 >= $_p}? '--'))))))
boolean	translateLeftRecursiveRule(GrammarRootAST ast, LeftRecursiveRule r, String language)	Return true if successful
void	translateLeftRecursiveRules()

Methods inherited from class java.lang.Object

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

Field Detail

PRECEDENCE_OPTION_NAME

public static final String PRECEDENCE_OPTION_NAME

See Also:

Constant Field Values

TOKENINDEX_OPTION_NAME

public static final String TOKENINDEX_OPTION_NAME

See Also:

Constant Field Values

ast

public GrammarRootAST ast

rules

public Collection<Rule> rules

g

public Grammar g

tool

public Tool tool

Constructor Detail

LeftRecursiveRuleTransformer

public LeftRecursiveRuleTransformer(GrammarRootAST ast,
                                    Collection<Rule> rules,
                                    Grammar g)

Method Detail

translateLeftRecursiveRules

public void translateLeftRecursiveRules()

translateLeftRecursiveRule

public boolean translateLeftRecursiveRule(GrammarRootAST ast,
                                          LeftRecursiveRule r,
                                          String language)

Return true if successful

parseArtificialRule

public RuleAST parseArtificialRule(Grammar g,
                                   String ruleText)

setAltASTPointers

public void setAltASTPointers(LeftRecursiveRule r,
                              RuleAST t)

 (RULE e int _p (returns int v)
        (BLOCK
          (ALT
                (BLOCK
                        (ALT INT {$v = $INT.int;})
                        (ALT '(' (= x e) ')' {$v = $x.v;})
                        (ALT ID))
                (* (BLOCK
                        (OPTIONS ...)
                        (ALT {7 >= $_p}? '*' (= b e) {$v = $a.v * $b.v;})
                        (ALT {6 >= $_p}? '+' (= b e) {$v = $a.v + $b.v;})
                        (ALT {3 >= $_p}? '++') (ALT {2 >= $_p}? '--'))))))