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/*
 * SonarQube JSON Analyzer
 * Copyright (C) 2015-2017 David RACODON
 * [email protected]
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.json.parser;

import com.sonar.sslr.api.GenericTokenType;
import org.sonar.sslr.grammar.GrammarRuleKey;
import org.sonar.sslr.grammar.LexerlessGrammarBuilder;

/*
 * See https://tools.ietf.org/html/rfc7159 and http://json.org/
 */
public enum JSONLexicalGrammar implements GrammarRuleKey {

  JSON,
  OBJECT,
  PAIR,
  KEY,
  ARRAY,
  VALUE,

  TRUE,
  FALSE,
  NULL,

  STRING,
  NUMBER,

  COMMA,
  COLON,
  LEFT_BRACE,
  RIGHT_BRACE,
  LEFT_BRACKET,
  RIGHT_BRACKET,

  BOM,
  EOF,

  SPACING;

  public static LexerlessGrammarBuilder createGrammar() {
    LexerlessGrammarBuilder b = LexerlessGrammarBuilder.create();
    syntax(b);
    b.setRootRule(JSON);
    return b;
  }

  private static void syntax(LexerlessGrammarBuilder b) {
    b.rule(TRUE).is(SPACING, "true");
    b.rule(FALSE).is(SPACING, "false");
    b.rule(NULL).is(SPACING, "null");

    b.rule(NUMBER).is(SPACING, b.regexp("[-]?[0-9]*\\.?[0-9]+([eE][-+]?[0-9]+)?"));
    b.rule(STRING).is(SPACING, b.regexp("\"([^\"\\\\]*+(\\\\([\\\\\"/bfnrt]|u[0-9a-fA-F]{4}))?+)*+\""));

    b.rule(COMMA).is(SPACING, ",");
    b.rule(COLON).is(SPACING, ":");
    b.rule(LEFT_BRACE).is(SPACING, "{");
    b.rule(RIGHT_BRACE).is(SPACING, "}");
    b.rule(LEFT_BRACKET).is(SPACING, "[");
    b.rule(RIGHT_BRACKET).is(SPACING, "]");

    b.rule(BOM).is("\ufeff");
    b.rule(EOF).is(SPACING, b.token(GenericTokenType.EOF, b.endOfInput()));

    b.rule(SPACING).is(b.skippedTrivia(b.regexp("(?