peg2 0.2.4 
peg2: ^0.2.4 copied to clipboard
PEG+ (Parsing expression grammar) parser source code generator, command line tool.
// Generated by 'peg2'
// https://pub.dev/packages/peg2
void main() {
final text = '''
{"rocket": "🚀 flies to the stars"}
''';
final parser = ExampleParser();
final result = parser.parse(text);
if (!parser.ok) {
throw parser.error!;
}
print(result);
}
class ExampleParser {
static const int _eof = 1114112;
static const List<String> _terminals = [
'\'end of file\'',
'\'false\'',
'\'leading spaces\'',
'\'null\'',
'\'true\'',
'\'string\'',
'\'number\'',
'\'{\'',
'\'}\'',
'\'[\'',
'\']\'',
'\',\'',
'\':\''
];
FormatException? error;
bool ok = false;
int _ch = 0;
int _failPos = -1;
int _failStart = -1;
int _failures0 = 0;
int _length = 0;
int _pos = 0;
String _source = '';
String? _unterminated;
dynamic parse(String source) {
_source = source;
_reset();
final result = _parseJson();
if (!ok) {
_buildError();
}
return result;
}
void _buildError() {
final sink = StringBuffer();
sink.write('Syntax error, ');
if (_unterminated != null) {
sink.write('unterminated ');
sink.write(_unterminated);
} else {
final names = <String>[];
final flags = <int>[];
flags.add(_failures0);
for (var i = 0, id = 0; i < flags.length; i++) {
final flag = flags[i];
for (var j = 0; j < 32; j++) {
final mask = 1 << j;
if (flag & mask != 0) {
final name = _terminals[id];
names.add(name);
}
id++;
}
}
names.sort();
if (names.isEmpty) {
if (_failStart == _length) {
sink.write('unexpected end of input');
} else {
sink.write('unexpected charcater ');
final ch = _getChar(_failStart);
if (ch >= 32 && ch < 126) {
sink.write('\'');
sink.write(String.fromCharCode(ch));
sink.write('\'');
} else {
sink.write('(');
sink.write(ch);
sink.write(')');
}
}
} else {
sink.write('expected ');
sink.write(names.join(', '));
}
}
error = FormatException(sink.toString(), _source, _failStart);
}
@pragma('vm:prefer-inline')
bool _fail(String name) {
if (_failStart > _pos) {
return false;
}
if (_failStart < _pos) {
_failStart = _pos;
_unterminated = null;
_failures0 = 0;
}
if (_failPos == _length) {
_unterminated = name;
}
return true;
}
@pragma('vm:prefer-inline')
int _getChar(int pos) {
if (pos < _source.length) {
var ch = _source.codeUnitAt(pos);
if (ch >= 0xD800 && ch <= 0xDBFF) {
if (pos + 1 < _source.length) {
final ch2 = _source.codeUnitAt(pos + 1);
if (ch2 >= 0xDC00 && ch2 <= 0xDFFF) {
ch = ((ch - 0xD800) << 10) + (ch2 - 0xDC00) + 0x10000;
} else {
throw FormatException('Unpaired high surrogate', _source, pos);
}
} else {
throw FormatException('The source has been exhausted', _source, pos);
}
} else {
if (ch >= 0xDC00 && ch <= 0xDFFF) {
throw FormatException(
'UTF-16 surrogate values are illegal in UTF-32', _source, pos);
}
}
return ch;
}
return _eof;
}
@pragma('vm:prefer-inline')
int? _matchAny() {
if (_ch == _eof) {
if (_failPos < _pos) {
_failPos = _pos;
}
ok = false;
return null;
}
final ch = _ch;
_pos += _ch <= 0xffff ? 1 : 2;
_ch = _getChar(_pos);
ok = true;
return ch;
}
@pragma('vm:prefer-inline')
T? _matchChar<T>(int ch, T? result) {
if (ch != _ch) {
if (_failPos < _pos) {
_failPos = _pos;
}
ok = false;
return null;
}
_pos += _ch <= 0xffff ? 1 : 2;
_ch = _getChar(_pos);
ok = true;
return result;
}
@pragma('vm:prefer-inline')
int? _matchRange(int start, int end) {
if (_ch >= start && _ch <= end) {
final ch = _ch;
_pos += _ch <= 0xffff ? 1 : 2;
_ch = _getChar(_pos);
ok = true;
return ch;
}
if (_failPos < _pos) {
_failPos = _pos;
}
ok = false;
return null;
}
@pragma('vm:prefer-inline')
int? _matchRanges(List<int> ranges) {
// Use binary search
for (var i = 0; i < ranges.length; i += 2) {
if (ranges[i] <= _ch) {
if (ranges[i + 1] >= _ch) {
final ch = _ch;
_pos += _ch <= 0xffff ? 1 : 2;
_ch = _getChar(_pos);
ok = true;
return ch;
}
} else {
break;
}
}
ok = false;
if (_failPos < _pos) {
_failPos = _pos;
}
return null;
}
@pragma('vm:prefer-inline')
String? _matchString(String text) {
var i = 0;
if (_ch == text.codeUnitAt(0)) {
i++;
if (_pos + text.length <= _source.length) {
for (; i < text.length; i++) {
if (text.codeUnitAt(i) != _source.codeUnitAt(_pos + i)) {
break;
}
}
}
}
ok = i == text.length;
if (ok) {
_pos = _pos + text.length;
_ch = _getChar(_pos);
return text;
} else {
final pos = _pos + i;
if (_failPos < pos) {
_failPos = pos;
}
return null;
}
}
@pragma('vm:prefer-inline')
int? _parse$$char() {
int? $0;
final $1 = _ch;
final $2 = _pos;
while (true) {
int? $3;
_matchChar(92, 92);
if (ok) {
final $4 = _parse$$escaped();
if (ok) {
final r = $4!;
$3 = r;
$0 = $3;
break;
}
}
_ch = $1;
_pos = $2;
int? $5;
final $6 = _parse$$unescaped();
if (ok) {
$5 = $6;
$0 = $5;
break;
}
_ch = $1;
break;
}
return $0;
}
@pragma('vm:prefer-inline')
int? _parse$$escaped() {
int? $0;
final $1 = _ch;
final $2 = _pos;
while (true) {
int? $3;
final $4 = _matchChar(34, 34);
if (ok) {
$3 = $4;
$0 = $3;
break;
}
_ch = $1;
int? $5;
final $6 = _matchChar(92, 92);
if (ok) {
$5 = $6;
$0 = $5;
break;
}
_ch = $1;
int? $7;
final $8 = _matchChar(47, 47);
if (ok) {
$7 = $8;
$0 = $7;
break;
}
_ch = $1;
int? $9;
_matchChar(98, 98);
if (ok) {
late int $$;
$$ = 0x8;
$9 = $$;
$0 = $9;
break;
}
_ch = $1;
int? $10;
_matchChar(102, 102);
if (ok) {
late int $$;
$$ = 0xC;
$10 = $$;
$0 = $10;
break;
}
_ch = $1;
int? $11;
_matchChar(110, 110);
if (ok) {
late int $$;
$$ = 0xA;
$11 = $$;
$0 = $11;
break;
}
_ch = $1;
int? $12;
_matchChar(114, 114);
if (ok) {
late int $$;
$$ = 0xD;
$12 = $$;
$0 = $12;
break;
}
_ch = $1;
int? $13;
_matchChar(116, 116);
if (ok) {
late int $$;
$$ = 0x9;
$13 = $$;
$0 = $13;
break;
}
_ch = $1;
int? $14;
_matchChar(117, 117);
if (ok) {
final $15 = _parse$$hexdig4();
if (ok) {
final r = $15!;
$14 = r;
$0 = $14;
break;
}
}
_ch = $1;
_pos = $2;
break;
}
return $0;
}
int? _parse$$hexdig() {
int? $0;
final $1 = _ch;
while (true) {
int? $2;
final $3 = _matchRange(97, 102);
if (ok) {
final v = $3!;
late int $$;
$$ = v - 97;
$2 = $$;
$0 = $2;
break;
}
_ch = $1;
int? $4;
final $5 = _matchRange(65, 70);
if (ok) {
final v = $5!;
late int $$;
$$ = v - 65;
$4 = $$;
$0 = $4;
break;
}
_ch = $1;
int? $6;
final $7 = _matchRange(48, 57);
if (ok) {
final v = $7!;
late int $$;
$$ = v - 48;
$6 = $$;
$0 = $6;
break;
}
_ch = $1;
break;
}
return $0;
}
@pragma('vm:prefer-inline')
int? _parse$$hexdig4() {
int? $0;
final $2 = _ch;
final $3 = _pos;
int? $4;
final $5 = _parse$$hexdig();
if (ok) {
final $6 = _parse$$hexdig();
if (ok) {
final $7 = _parse$$hexdig();
if (ok) {
final $8 = _parse$$hexdig();
if (ok) {
final a = $5!;
final b = $6!;
final c = $7!;
final d = $8!;
late int $$;
$$ = a * 0xfff + b * 0xff + c * 0xf + d;
$4 = $$;
$0 = $4;
}
}
}
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
List<int>? _parse$$spacing() {
while (true) {
const $0 = [9, 10, 13, 13, 32, 32];
_matchRanges($0);
if (!ok) {
break;
}
}
ok = true;
return null;
}
@pragma('vm:prefer-inline')
int? _parse$$unescaped() {
int? $0;
final $1 = _ch;
while (true) {
int? $2;
final $3 = _matchRange(32, 33);
if (ok) {
$2 = $3;
$0 = $2;
break;
}
_ch = $1;
int? $4;
final $5 = _matchRange(35, 91);
if (ok) {
$4 = $5;
$0 = $4;
break;
}
_ch = $1;
int? $6;
final $7 = _matchRange(93, 1114111);
if (ok) {
$6 = $7;
$0 = $6;
break;
}
_ch = $1;
break;
}
return $0;
}
@pragma('vm:prefer-inline')
List? _parseArray() {
List? $0;
final $2 = _ch;
final $3 = _pos;
List? $4;
_parse_$LeftSquareBracket();
if (ok) {
final $6 = _parseValues();
final $5 = $6;
ok = true;
_parse_$RightSquareBracket();
if (ok) {
final v = $5;
late List $$;
$$ = v ?? [];
$4 = $$;
$0 = $4;
}
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
@pragma('vm:prefer-inline')
dynamic _parseJson() {
dynamic $0;
final $2 = _ch;
final $3 = _pos;
dynamic $4;
_parse_leading_spaces();
final $5 = _parseValue();
if (ok) {
_parse_end_of_file();
if (ok) {
final v = $5;
$4 = v;
$0 = $4;
}
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
MapEntry<String, dynamic>? _parseMember() {
MapEntry<String, dynamic>? $0;
final $2 = _ch;
final $3 = _pos;
MapEntry<String, dynamic>? $4;
final $5 = _parse_string();
if (ok) {
_parse_$Colon();
if (ok) {
final $6 = _parseValue();
if (ok) {
final k = $5!;
final v = $6;
late MapEntry<String, dynamic> $$;
$$ = MapEntry(k, v);
$4 = $$;
$0 = $4;
}
}
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
@pragma('vm:prefer-inline')
List<MapEntry<String, dynamic>>? _parseMembers() {
List<MapEntry<String, dynamic>>? $0;
final $2 = _ch;
final $3 = _pos;
List<MapEntry<String, dynamic>>? $4;
final $5 = _parseMember();
if (ok) {
List<MapEntry<String, dynamic>>? $6;
final $7 = <MapEntry<String, dynamic>>[];
while (true) {
MapEntry<String, dynamic>? $8;
final $10 = _ch;
final $11 = _pos;
MapEntry<String, dynamic>? $12;
_parse_$Comma();
if (ok) {
final $13 = _parseMember();
if (ok) {
final m = $13!;
$12 = m;
$8 = $12;
}
}
if (!ok) {
_ch = $10;
_pos = $11;
}
if (!ok) {
break;
}
$7.add($8!);
}
if (ok = true) {
$6 = $7;
}
final m = $5!;
final n = $6!;
late List<MapEntry<String, dynamic>> $$;
$$ = [m, ...n];
$4 = $$;
$0 = $4;
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
@pragma('vm:prefer-inline')
Map<String, dynamic>? _parseObject() {
Map<String, dynamic>? $0;
final $2 = _ch;
final $3 = _pos;
Map<String, dynamic>? $4;
_parse_$LeftBrace();
if (ok) {
final $6 = _parseMembers();
final $5 = $6;
ok = true;
_parse_$RightBrace();
if (ok) {
final m = $5;
late Map<String, dynamic> $$;
$$ = <String, dynamic>{}..addEntries(m ?? []);
$4 = $$;
$0 = $4;
}
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
dynamic _parseValue() {
dynamic $0;
final $1 = _ch;
while (true) {
List? $2;
final $3 = _parseArray();
if (ok) {
$2 = $3;
$0 = $2;
break;
}
_ch = $1;
dynamic $4;
final $5 = _parse_false();
if (ok) {
$4 = $5;
$0 = $4;
break;
}
_ch = $1;
dynamic $6;
final $7 = _parse_null();
if (ok) {
$6 = $7;
$0 = $6;
break;
}
_ch = $1;
dynamic $8;
final $9 = _parse_true();
if (ok) {
$8 = $9;
$0 = $8;
break;
}
_ch = $1;
Map<String, dynamic>? $10;
final $11 = _parseObject();
if (ok) {
$10 = $11;
$0 = $10;
break;
}
_ch = $1;
num? $12;
final $13 = _parse_number();
if (ok) {
$12 = $13;
$0 = $12;
break;
}
_ch = $1;
String? $14;
final $15 = _parse_string();
if (ok) {
$14 = $15;
$0 = $14;
break;
}
_ch = $1;
break;
}
return $0;
}
@pragma('vm:prefer-inline')
List? _parseValues() {
List? $0;
final $2 = _ch;
final $3 = _pos;
List? $4;
final $5 = _parseValue();
if (ok) {
List? $6;
final $7 = <dynamic>[];
while (true) {
dynamic $8;
final $10 = _ch;
final $11 = _pos;
dynamic $12;
_parse_$Comma();
if (ok) {
final $13 = _parseValue();
if (ok) {
final v = $13;
$12 = v;
$8 = $12;
}
}
if (!ok) {
_ch = $10;
_pos = $11;
}
if (!ok) {
break;
}
$7.add($8);
}
if (ok = true) {
$6 = $7;
}
final v = $5;
final n = $6!;
late List $$;
$$ = [v, ...n];
$4 = $$;
$0 = $4;
}
if (!ok) {
_ch = $2;
_pos = $3;
}
return $0;
}
@pragma('vm:prefer-inline')
String? _parse_$Colon() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
_matchChar(58, ':');
if (ok) {
_parse$$spacing();
}
if (!ok) {
_ch = $0;
_pos = $1;
if (_fail('\':\'')) {
_failures0 |= 0x1000;
}
}
return null;
}
String? _parse_$Comma() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
_matchChar(44, ',');
if (ok) {
_parse$$spacing();
}
if (!ok) {
_ch = $0;
_pos = $1;
if (_fail('\',\'')) {
_failures0 |= 0x800;
}
}
return null;
}
@pragma('vm:prefer-inline')
String? _parse_$LeftBrace() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
_matchChar(123, '{');
if (ok) {
_parse$$spacing();
}
if (!ok) {
_ch = $0;
_pos = $1;
if (_fail('\'{\'')) {
_failures0 |= 0x80;
}
}
return null;
}
@pragma('vm:prefer-inline')
String? _parse_$LeftSquareBracket() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
_matchChar(91, '[');
if (ok) {
_parse$$spacing();
}
if (!ok) {
_ch = $0;
_pos = $1;
if (_fail('\'[\'')) {
_failures0 |= 0x200;
}
}
return null;
}
@pragma('vm:prefer-inline')
String? _parse_$RightBrace() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
_matchChar(125, '}');
if (ok) {
_parse$$spacing();
}
if (!ok) {
_ch = $0;
_pos = $1;
if (_fail('\'}\'')) {
_failures0 |= 0x100;
}
}
return null;
}
@pragma('vm:prefer-inline')
String? _parse_$RightSquareBracket() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
_matchChar(93, ']');
if (ok) {
_parse$$spacing();
}
if (!ok) {
_ch = $0;
_pos = $1;
if (_fail('\']\'')) {
_failures0 |= 0x400;
}
}
return null;
}
@pragma('vm:prefer-inline')
dynamic _parse_end_of_file() {
_failPos = _pos;
final $0 = _ch;
final $1 = _pos;
final $2 = _failPos;
final $3 = _failStart;
final $4 = _failures0;
_matchAny();
_ch = $0;
_pos = $1;
_failPos = $2;
_failStart = $3;
_failures0 = $4;
ok = !ok;
if (!ok) {
if (_fail('\'end of file\'')) {
_failures0 |= 0x1;
}
}
return null;
}
@pragma('vm:prefer-inline')
dynamic _parse_false() {
_failPos = _pos;
dynamic $0;
final $2 = _ch;
final $3 = _pos;
dynamic $4;
_matchString('false');
if (ok) {
_parse$$spacing();
dynamic $$;
$$ = false;
$4 = $$;
$0 = $4;
}
if (!ok) {
_ch = $2;
_pos = $3;
if (_fail('\'false\'')) {
_failures0 |= 0x2;
}
}
return $0;
}
@pragma('vm:prefer-inline')
List<int>? _parse_leading_spaces() {
_parse$$spacing();
return null;
}
@pragma('vm:prefer-inline')
dynamic _parse_null() {
_failPos = _pos;
dynamic $0;
final $2 = _ch;
final $3 = _pos;
dynamic $4;
_matchString('null');
if (ok) {
_parse$$spacing();
dynamic $$;
$$ = null;
$4 = $$;
$0 = $4;
}
if (!ok) {
_ch = $2;
_pos = $3;
if (_fail('\'null\'')) {
_failures0 |= 0x8;
}
}
return $0;
}
@pragma('vm:prefer-inline')
num? _parse_number() {
_failPos = _pos;
num? $0;
final $2 = _ch;
final $3 = _pos;
num? $4;
String? $5;
final $6 = _pos;
final $7 = _ch;
final $8 = _pos;
_matchChar(45, 45);
ok = true;
final $9 = _ch;
final $10 = _pos;
while (true) {
_matchChar(48, 48);
if (ok) {
break;
}
_ch = $9;
_matchRange(49, 57);
if (ok) {
while (true) {
_matchRange(48, 57);
if (!ok) {
break;
}
}
ok = true;
}
if (ok) {
break;
}
_ch = $9;
_pos = $10;
break;
}
if (ok) {
final $11 = _ch;
final $12 = _pos;
_matchChar(46, 46);
if (ok) {
var $13 = 0;
while (true) {
_matchRange(48, 57);
if (!ok) {
break;
}
$13++;
}
ok = $13 != 0;
}
if (!ok) {
_ch = $11;
_pos = $12;
}
ok = true;
final $14 = _ch;
final $15 = _pos;
const $16 = [69, 69, 101, 101];
_matchRanges($16);
if (ok) {
const $17 = [43, 43, 45, 45];
_matchRanges($17);
ok = true;
var $18 = 0;
while (true) {
_matchRange(48, 57);
if (!ok) {
break;
}
$18++;
}
ok = $18 != 0;
}
if (!ok) {
_ch = $14;
_pos = $15;
}
ok = true;
}
if (!ok) {
_ch = $7;
_pos = $8;
}
if (ok) {
$5 = _source.substring($6, _pos);
}
if (ok) {
_parse$$spacing();
final n = $5!;
late num $$;
$$ = num.parse(n);
$4 = $$;
$0 = $4;
}
if (!ok) {
_ch = $2;
_pos = $3;
if (_fail('\'number\'')) {
_failures0 |= 0x40;
}
}
return $0;
}
String? _parse_string() {
_failPos = _pos;
String? $0;
final $2 = _ch;
final $3 = _pos;
String? $4;
_matchChar(34, '"');
if (ok) {
List<int>? $5;
final $6 = <int>[];
while (true) {
final $7 = _parse$$char();
if (!ok) {
break;
}
$6.add($7!);
}
if (ok = true) {
$5 = $6;
}
_matchChar(34, '"');
if (ok) {
_parse$$spacing();
final c = $5!;
late String $$;
$$ = String.fromCharCodes(c);
$4 = $$;
$0 = $4;
}
}
if (!ok) {
_ch = $2;
_pos = $3;
if (_fail('\'string\'')) {
_failures0 |= 0x20;
}
}
return $0;
}
@pragma('vm:prefer-inline')
dynamic _parse_true() {
_failPos = _pos;
dynamic $0;
final $2 = _ch;
final $3 = _pos;
dynamic $4;
_matchString('true');
if (ok) {
_parse$$spacing();
dynamic $$;
$$ = true;
$4 = $$;
$0 = $4;
}
if (!ok) {
_ch = $2;
_pos = $3;
if (_fail('\'true\'')) {
_failures0 |= 0x10;
}
}
return $0;
}
void _reset() {
error = null;
_failPos = 0;
_failStart = 0;
_failures0 = 0;
_length = _source.length;
_pos = 0;
_unterminated = null;
_ch = _getChar(0);
ok = false;
}
}
// ignore_for_file: non_constant_identifier_names
// ignore_for_file: unused_elementMetadata
1
likes
0
pub points
0%
popularity
Publisher
unverified uploader
Metadata
PEG+ (Parsing expression grammar) parser source code generator, command line tool.
Repository (GitHub)
View/report issues
License
unknown (LICENSE)
Dependencies
args, code_builder, dart_style, enumerable, lists, meta, path, strings
