strings.dart

import 'package:json_path/src/grammar/child_selector.dart';
import 'package:json_path/src/grammar/parser_ext.dart';
import 'package:petitparser/petitparser.dart';

final _escape = char(r'\');
final _doubleQuote = char('"');

final _singleQuote = char("'");

final _escapedSlash = string(r'\/').value(r'/');
final _escapedBackSlash = string(r'\\').value(r'\');

final _escapedBackspace = string(r'\b').value('\b');
final _escapedFormFeed = string(r'\f').value('\f');

final _escapedNewLine = string(r'\n').value('\n');
final _escapedReturn = string(r'\r').value('\r');
final _escapedTab = string(r'\t').value('\t');
final _escapedControl = [
  _escapedSlash,
  _escapedBackSlash,
  _escapedBackspace,
  _escapedFormFeed,
  _escapedNewLine,
  _escapedReturn,
  _escapedTab
].toChoiceParser();

// The highest unicode character
final _unicodeBoundary = String.fromCharCode(0xFFFF);

// Exclude double quote '"' and back slash '\'
final _doubleUnescaped = [
  range(' ', '!'),
  range('#', '['),
  range(']', _unicodeBoundary)
].toChoiceParser();

final _hexDigit = anyOf('0123456789ABCDEFabcdef');

final _unicodeSymbol = (string(r'\u') & _hexDigit.timesString(4))
    .map((value) => String.fromCharCode(int.parse(value.last, radix: 16)));

final _escapedDoubleQuote = (_escape & _doubleQuote).map((_) => '"');

final _doubleInner = [
  _doubleUnescaped,
  _escapedDoubleQuote,
  _escapedControl,
  _unicodeSymbol
].toChoiceParser().star().join();

// Exclude single quote "'" and back slash "\"
final _singleUnescaped = [
  range(' ', '&'),
  range('(', '['),
  range(']', _unicodeBoundary)
].toChoiceParser();

final _escapedSingleQuote = (_escape & _singleQuote).map((_) => "'");

final _singleInner = [
  _singleUnescaped,
  _escapedSingleQuote,
  _escapedControl,
  _unicodeSymbol
].toChoiceParser().star().join();

final _doubleQuotedString =
    _doubleInner.skip(before: _doubleQuote, after: _doubleQuote);

final _singleQuotedString =
    _singleInner.skip(before: _singleQuote, after: _singleQuote);

final _nameFirst =
    (char('_') | letter() | range(String.fromCharCode(0x80), _unicodeBoundary))
        .plus()
        .flatten('a correct member name expected');

final _nameChar = digit() | _nameFirst;

final quotedString = (_singleQuotedString | _doubleQuotedString).cast<String>();

final memberNameShorthand = (_nameFirst & _nameChar.star())
    .flatten('a member name shorthand expected')
    .map(childSelector);