Package org.antlr.v4.codegen.model

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

/*
* [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,
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package org.antlr.v4.codegen.model;

import org.antlr.v4.codegen.ActionTranslator;
import org.antlr.v4.codegen.CodeGenerator;
import org.antlr.v4.codegen.OutputModelFactory;
import org.antlr.v4.codegen.model.chunk.ActionChunk;
import org.antlr.v4.runtime.atn.AbstractPredicateTransition;
import org.antlr.v4.runtime.misc.NotNull;
import org.antlr.v4.tool.ast.ActionAST;
import org.antlr.v4.tool.ast.GrammarAST;

import java.util.List;

/** */
public class SemPred extends Action {
  /**
   * The user-specified terminal option {@code fail}, if it was used and the
   * value is a string literal. For example:
   *
   * <p>
   * {@code {pred}?<fail='message'>}</p>
   */
  public String msg;
  /**
   * The predicate string with <code>{</code> and <code>}?</code> stripped from the ends.
   */
  public String predicate;

  /**
   * The translated chunks of the user-specified terminal option {@code fail},
   * if it was used and the value is an action. For example:
   *
   * <p>
   * {@code {pred}?<fail={"Java literal"}>}</p>
   */
  @ModelElement public List<ActionChunk> failChunks;

  public SemPred(OutputModelFactory factory, @NotNull ActionAST ast) {
    super(factory,ast);

    assert ast.atnState != null
      && ast.atnState.getNumberOfTransitions() == 1
      && ast.atnState.transition(0) instanceof AbstractPredicateTransition;

    GrammarAST failNode = ast.getOptionAST("fail");
    CodeGenerator gen = factory.getGenerator();
    predicate = ast.getText();
    if (predicate.startsWith("{") && predicate.endsWith("}?")) {
      predicate = predicate.substring(1, predicate.length() - 2);
    }
    predicate = gen.getTarget().getTargetStringLiteralFromString(predicate);

    if ( failNode==null ) return;

    if ( failNode instanceof ActionAST ) {
      ActionAST failActionNode = (ActionAST)failNode;
      RuleFunction rf = factory.getCurrentRuleFunction();
      failChunks = ActionTranslator.translateAction(factory, rf,
                              failActionNode.token,
                              failActionNode);
    }
    else {
      msg = gen.getTarget().getTargetStringLiteralFromANTLRStringLiteral(gen,
                                      failNode.getText(),
                                      true);
    }
  }
}
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