petitparser/lib/src/json/grammar.dart

part of json;

/**
 * JSON grammar.
 */
class JsonGrammar extends GrammarParser {
  JsonGrammar() : super(new JsonGrammarDefinition());
}

/**
 * JSON grammar definition.
 */
class JsonGrammarDefinition extends GrammarDefinition {

  final _escapeTable = const {
    '\\': '\\',
    '/': '/',
    '"': '"',
    'b': '\b',
    'f': '\f',
    'n': '\n',
    'r': '\r',
    't': '\t'
  };

  start() => ref(value).end();
  token(p) => p.flatten().trim();

  array() => ref(token, char('['))
      & ref(elements).optional()
      & ref(token, char(']'));
  elements() => ref(value).separatedBy(ref(token, char(',')), includeSeparators: false);
  members() => ref(pair).separatedBy(ref(token, char(',')), includeSeparators: false);
  object() => ref(token, char('{'))
      & ref(members).optional()
      & ref(token, char('}'));
  pair() => ref(stringToken)
      & ref(token, char(':'))
      & ref(value);
  value() => ref(stringToken)
      | ref(numberToken)
      | ref(object)
      | ref(array)
      | ref(trueToken)
      | ref(falseToken)
      | ref(nullToken);

  trueToken() => ref(token, string('true'));
  falseToken() => ref(token, string('false'));
  nullToken() => ref(token, string('null'));
  stringToken() => ref(token, ref(stringPrimitive));
  numberToken() => ref(token, ref(numberPrimitive));

  characterPrimitive() => ref(characterNormal)
      | ref(characterEscape)
      | ref(characterOctal);
  characterNormal() => pattern('^"\\');
  characterEscape() => char('\\')
      & pattern(new List.from(_escapeTable.keys).join());
  characterOctal() => string('\\u').seq(pattern("0-9A-Fa-f").times(4).flatten());
  numberPrimitive() => char('-').optional()
      & char('0').or(digit().plus())
      & char('.').seq(digit().plus()).optional()
      & pattern('eE').seq(pattern('-+').optional()).seq(digit().plus()).optional();
  stringPrimitive() => char('"')
      & ref(characterPrimitive).star()
      & char('"');

}