petitparser/lib/src/lisp/grammar.dart

part of lisp;

/**
 * LISP grammar.
 */
class LispGrammar extends GrammarParser {
  LispGrammar() : super(new LispGrammarDefinition());
}

/**
 * LISP grammar definition.
 */
class LispGrammarDefinition extends GrammarDefinition {

  start() => ref(atom).star().end();

  atom() => ref(atom_).trim(ref(space));
  atom_() => ref(list)
      | ref(number)
      | ref(string)
      | ref(symbol)
      | ref(quote)
      | ref(quasiquote)
      | ref(unquote)
      | ref(splice);

  list() => ref(bracket, '()', ref(cells))
      | ref(bracket, '[]', ref(cells))
      | ref(bracket, '{}', ref(cells));
  cells() => ref(cell)
      | ref(empty);
  cell() => ref(atom) & ref(cells);
  empty() => ref(space).star();

  number() => ref(number_).flatten();
  number_() => anyIn('-+').optional()
      & char('0').or(digit().plus())
      & char('.').seq(digit().plus()).optional()
      & anyIn('eE').seq(anyIn('-+').optional()).seq(digit().plus()).optional();

  string() => ref(bracket, '""', ref(character).star());
  character() => ref(characterEscape) | ref(characterRaw);
  characterEscape() => char('\\') & any();
  characterRaw() => pattern('^"');

  symbol() => ref(symbol_).flatten();
  symbol_() => pattern('a-zA-Z!#\$%&*/:<=>?@\\^_|~+-')
      & pattern('a-zA-Z0-9!#\$%&*/:<=>?@\\^_|~+-').star();

  quote() => char('\'') & ref(list);
  quasiquote() => char('`') & ref(list);
  unquote() => char(',') & ref(list);
  splice() => char('@') & ref(list);

  space() => whitespace() | ref(comment);
  comment() => char(';') & Token.newlineParser().neg().star();
  bracket(String brackets, Parser parser) => char(brackets[0]) & parser & char(brackets[1]);

}