Package org.antlr.v4.codegen.model

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

/*
* [The "BSD license"]
*  Copyright (c) 2012 Terence Parr
*  Copyright (c) 2012 Sam Harwell
*  All rights reserved.
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*  1. Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*  2. Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in the
*     documentation and/or other materials provided with the distribution.
*  3. The name of the author may not be used to endorse or promote products
*     derived from this software without specific prior written permission.
*
*  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
*  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
*  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
*  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
*  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
*  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
*  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
*  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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*  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

package org.antlr.v4.codegen.model;

import org.antlr.v4.codegen.OutputModelFactory;
import org.antlr.v4.codegen.model.decl.Decl;
import org.antlr.v4.codegen.model.decl.TokenTypeDecl;
import org.antlr.v4.misc.Utils;
import org.antlr.v4.runtime.misc.IntervalSet;
import org.antlr.v4.tool.ast.GrammarAST;

import java.util.ArrayList;
import java.util.List;

/** The class hierarchy underneath SrcOp is pretty deep but makes sense that,
*  for example LL1StarBlock is a kind of LL1Loop which is a kind of Choice.
*  The problem is it's impossible to figure
*  out how to construct one of these deeply nested objects because of the
*  long super constructor call chain. Instead, I decided to in-line all of
*  this and then look for opportunities to re-factor code into functions.
*  It makes sense to use a class hierarchy to share data fields, but I don't
*  think it makes sense to factor code using super constructors because
*  it has too much work to do.
*/
public abstract class Choice extends RuleElement {
  public int decision = -1;
  public Decl label;

  @ModelElement public List<CodeBlockForAlt> alts;
  @ModelElement public List<SrcOp> preamble = new ArrayList<SrcOp>();

  public Choice(OutputModelFactory factory,
          GrammarAST blkOrEbnfRootAST,
          List<CodeBlockForAlt> alts)
  {
    super(factory, blkOrEbnfRootAST);
    this.alts = alts;
  }

  public void addPreambleOp(SrcOp op) {
    preamble.add(op);
  }

  public List<String[]> getAltLookaheadAsStringLists(IntervalSet[] altLookSets) {
    List<String[]> altLook = new ArrayList<String[]>();
    for (IntervalSet s : altLookSets) {
      altLook.add(factory.getGenerator().getTarget().getTokenTypesAsTargetLabels(factory.getGrammar(), s.toArray()));
    }
    return altLook;
  }

  public TestSetInline addCodeForLookaheadTempVar(IntervalSet look) {
    List<SrcOp> testOps = factory.getLL1Test(look, ast);
    TestSetInline expr = Utils.find(testOps, TestSetInline.class);
    if (expr != null) {
      Decl d = new TokenTypeDecl(factory, expr.varName);
      factory.getCurrentRuleFunction().addLocalDecl(d);
      CaptureNextTokenType nextType = new CaptureNextTokenType(factory,expr.varName);
      addPreambleOp(nextType);
    }
    return expr;
  }

  public ThrowNoViableAlt getThrowNoViableAlt(OutputModelFactory factory,
                        GrammarAST blkAST,
                        IntervalSet expecting) {
    return new ThrowNoViableAlt(factory, blkAST, expecting);
  }
}
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