/// Parses a JSON encoded `true`
/// @param {String} $source - JSON complete source
/// @param {Number} $pointer - current pointer
/// @throw Unexpected token `t`.
/// @return {List} - (new pointer, true)
/// @require {function} _throw
@function _json-decode--true($source, $pointer) {
  $length: str-length($source);

  @if $length - $pointer < 2
  or str-slice($source, $pointer, $pointer) != 'r'
  or str-slice($source, $pointer + 1, $pointer + 1) != 'u'
  or str-slice($source, $pointer + 2, $pointer + 2) != 'e' {
    @return _throw("Unexpected token: `t`.", $pointer);
  }

  @return ($pointer + 3, true);
}

/// Parses a JSON encoded `false`
/// @param {String} $source - JSON complete source
/// @param {Number} $pointer - current pointer
/// @throw Unexpected token `f`.
/// @return {List} - (new pointer, false)
/// @require {function} _throw
@function _json-decode--false($source, $pointer) {
  $length: str-length($source);

  @if $length - $pointer < 3
  or str-slice($source, $pointer, $pointer) != 'a'
  or str-slice($source, $pointer + 1, $pointer + 1) != 'l'
  or str-slice($source, $pointer + 2, $pointer + 2) != 's'
  or str-slice($source, $pointer + 3, $pointer + 3) != 'e' {
    @return _throw("Unexpected token: `f`.", $pointer);
  }

  @return ($pointer + 4, false);
}