Package org.antlr.v4.codegen.model

Source Code of org.antlr.v4.codegen.model.LeftRecursiveRuleFunction

/*
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*  Copyright (c) 2012 Terence Parr
*  Copyright (c) 2012 Sam Harwell
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package org.antlr.v4.codegen.model;

import org.antlr.v4.codegen.CodeGenerator;
import org.antlr.v4.codegen.OutputModelFactory;
import org.antlr.v4.codegen.model.decl.RuleContextDecl;
import org.antlr.v4.codegen.model.decl.RuleContextListDecl;
import org.antlr.v4.codegen.model.decl.StructDecl;
import org.antlr.v4.parse.ANTLRParser;
import org.antlr.v4.runtime.misc.Pair;
import org.antlr.v4.tool.LeftRecursiveRule;
import org.antlr.v4.tool.Rule;
import org.antlr.v4.tool.ast.GrammarAST;

public class LeftRecursiveRuleFunction extends RuleFunction {
  public LeftRecursiveRuleFunction(OutputModelFactory factory, LeftRecursiveRule r) {
    super(factory, r);

    CodeGenerator gen = factory.getGenerator();
    // Since we delete x=lr, we have to manually add decls for all labels
    // on left-recur refs to proper structs
    for (Pair<GrammarAST,String> pair : r.leftRecursiveRuleRefLabels) {
      GrammarAST idAST = pair.a;
      String altLabel = pair.b;
      String label = idAST.getText();
      GrammarAST rrefAST = (GrammarAST)idAST.getParent().getChild(1);
      if ( rrefAST.getType() == ANTLRParser.RULE_REF ) {
        Rule targetRule = factory.getGrammar().getRule(rrefAST.getText());
        String ctxName = gen.getTarget().getRuleFunctionContextStructName(targetRule);
        RuleContextDecl d;
        if (idAST.getParent().getType() == ANTLRParser.ASSIGN) {
          d = new RuleContextDecl(factory, label, ctxName);
        }
        else {
          d = new RuleContextListDecl(factory, label, ctxName);
        }

        StructDecl struct = ruleCtx;
        if ( altLabelCtxs!=null ) {
          StructDecl s = altLabelCtxs.get(altLabel);
          if ( s!=null ) struct = s; // if alt label, use subctx
        }
        struct.addDecl(d); // stick in overall rule's ctx
      }
    }
  }
}
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