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reflection_test.dart
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reflection_test.dart
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import 'package:petitparser/petitparser.dart';
import 'package:petitparser/reflection.dart';
import 'package:petitparser/src/reflection/internal/linter_rules.dart'
as linter_rules;
import 'package:petitparser/src/reflection/internal/optimize_rules.dart'
as optimize_rules;
import 'package:test/test.dart';
import 'utils/matchers.dart';
// Güting, Erwig, Übersetzerbau, Springer (p.63)
Map<Symbol, Parser> createUebersetzerbau() {
final grammar = <Symbol, Parser>{};
grammar[#a] = char('a');
grammar[#b] = char('b');
grammar[#c] = char('c');
grammar[#d] = char('d');
grammar[#e] = epsilon();
grammar[#B] = grammar[#b]! | grammar[#e]!;
grammar[#A] = grammar[#a]! | grammar[#B]!;
grammar[#S] = grammar[#A]! & grammar[#B]! & grammar[#c]! & grammar[#d]!;
return grammar;
}
// The canonical grammar to exercise first- and follow-set calculation,
// likely originally from the dragon-book.
Map<Symbol, Parser> createDragon() {
final grammar = <Symbol, SettableParser<dynamic>>{
for (final symbol in [#E, #Ep, #T, #Tp, #F]) symbol: undefined(),
};
grammar[#E]!.set(grammar[#T]! & grammar[#Ep]!);
grammar[#Ep]!.set((char('+') & grammar[#T]! & grammar[#Ep]!).optional());
grammar[#T]!.set(grammar[#F]! & grammar[#Tp]!);
grammar[#Tp]!.set((char('*') & grammar[#F]! & grammar[#Tp]!).optional());
grammar[#F]!.set((char('(') & grammar[#E]! & char(')')) | char('i'));
return grammar;
}
// A highly ambiguous grammar by Saichaitanya Jampana. Exploring the problem of
// ambiguity in context-free grammars.
Map<Symbol, Parser> createAmbiguous() {
final grammar = <Symbol, SettableParser<dynamic>>{
for (final symbol in [#S, #A, #a, #B, #b]) symbol: undefined(),
};
grammar[#S]!.set((grammar[#A]! & grammar[#B]!) | grammar[#a]!);
grammar[#A]!.set((grammar[#S]! & grammar[#B]!) | grammar[#b]!);
grammar[#a]!.set(char('a'));
grammar[#B]!.set((grammar[#B]! & grammar[#A]!) | grammar[#a]!);
grammar[#b]!.set(char('b'));
return grammar;
}
// A highly recursive parser.
Map<Symbol, Parser> createRecursive() {
final grammar = <Symbol, SettableParser<dynamic>>{
for (final symbol in [#S, #P, #p, #+]) symbol: undefined(),
};
grammar[#S]!.set(grammar[#P]! | grammar[#p]!);
grammar[#P]!.set(grammar[#S]! & grammar[#+]! & grammar[#S]!);
grammar[#p]!.set(char('p'));
grammar[#+]!.set(char('+'));
return grammar;
}
// A parser that references itself.
Parser<void> createSelfReference() {
final parser = undefined<void>();
parser.set(parser);
return parser;
}
void expectTerminals(Iterable<Parser> parsers, Iterable<String> inputs) {
final expectedInputs = {...inputs};
final actualInputs = {
for (final parser in [for (final parser in parsers) parser.end()])
for (final character in [
for (var code = 32; code <= 126; code++) String.fromCharCode(code),
'',
])
if (parser.accept(character)) character
};
expect(actualInputs, expectedInputs);
}
class PluggableLinterRule extends LinterRule {
const PluggableLinterRule(super.type, super.title, this._run);
final void Function(LinterRule rule, Analyzer, Parser, LinterCallback) _run;
@override
void run(Analyzer analyzer, Parser parser, LinterCallback callback) =>
_run(this, analyzer, parser, callback);
}
class PluggableOptimizeRule extends OptimizeRule {
const PluggableOptimizeRule(this._run);
final void Function<R>(OptimizeRule rule, Analyzer analyzer, Parser<R> parser,
ReplaceParser<R> replace) _run;
@override
void run<R>(Analyzer analyzer, Parser<R> parser, ReplaceParser<R> replace) =>
_run<R>(this, analyzer, parser, replace);
}
void main() {
group('analyzer', () {
test('root', () {
final parser = char('a').plus();
final analyzer = Analyzer(parser);
expect(analyzer.root, parser);
});
test('parsers', () {
final parser = char('a').plus();
final analyzer = Analyzer(parser);
expect(analyzer.parsers, {parser, parser.children.first});
});
group('allChildren', () {
test('single', () {
final inner = char('a');
final parser = inner.plus();
final analyzer = Analyzer(parser);
expect(analyzer.allChildren(parser), {inner});
expect(analyzer.allChildren(inner), isEmpty);
});
test('multiple', () {
final inner1 = char('a');
final inner2 = char('b');
final parser = inner1 & inner2;
final analyzer = Analyzer(parser);
expect(analyzer.allChildren(parser), {inner1, inner2});
expect(analyzer.allChildren(inner1), isEmpty);
expect(analyzer.allChildren(inner2), isEmpty);
});
test('repeated', () {
final inner1 = char('a');
final inner2 = char('b');
final parser = inner1 | inner2 | inner2;
final analyzer = Analyzer(parser);
expect(analyzer.allChildren(parser), {inner1, inner2});
expect(analyzer.allChildren(inner1), isEmpty);
expect(analyzer.allChildren(inner2), isEmpty);
});
test('recursive', () {
final inner1 = char('a');
final inner2 = undefined<String>();
final parser = [inner1, inner2].toChoiceParser();
inner2.set(parser);
final analyzer = Analyzer(parser);
expect(analyzer.allChildren(parser), {inner1, inner2, parser});
expect(analyzer.allChildren(inner1), isEmpty);
expect(analyzer.allChildren(inner2), {inner1, inner2, parser});
});
test('übersetzerbau grammar', () {
final parsers = createUebersetzerbau();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.allChildren(parsers[#S]!), {
parsers[#A],
parsers[#B],
parsers[#a],
parsers[#b],
parsers[#c],
parsers[#d],
parsers[#e],
});
expect(analyzer.allChildren(parsers[#A]!), {
parsers[#B],
parsers[#a],
parsers[#b],
parsers[#e],
});
expect(analyzer.allChildren(parsers[#B]!), {
parsers[#b],
parsers[#e],
});
expect(analyzer.allChildren(parsers[#a]!), isEmpty);
expect(analyzer.allChildren(parsers[#b]!), isEmpty);
expect(analyzer.allChildren(parsers[#c]!), isEmpty);
expect(analyzer.allChildren(parsers[#d]!), isEmpty);
expect(analyzer.allChildren(parsers[#e]!), isEmpty);
});
test('recursive grammar', () {
final parsers = createRecursive();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.allChildren(parsers[#S]!), analyzer.parsers);
expect(analyzer.allChildren(parsers[#P]!), analyzer.parsers);
expect(analyzer.allChildren(parsers[#p]!), {
parsers[#p]!.children.first,
});
expect(analyzer.allChildren(parsers[#+]!), {
parsers[#+]!.children.first,
});
});
test('self reference', () {
final parser = createSelfReference();
final analyzer = Analyzer(parser);
expect(analyzer.allChildren(parser), {parser});
});
});
group('findPath', () {
test('simple', () {
final parser = char('a');
final analyzer = Analyzer(parser);
final path = analyzer.findPathTo(parser, parser)!;
expect(path.source, parser);
expect(path.target, parser);
expect(path.parsers, [parser]);
expect(path.indexes, isEmpty);
final paths = analyzer.findAllPathsTo(parser, parser).toList();
expect(paths, hasLength(1));
expect(paths[0].parsers, [parser]);
expect(paths[0].indexes, isEmpty);
});
test('choice', () {
final terminal = char('a');
final parser = terminal | terminal;
final analyzer = Analyzer(parser);
final path = analyzer.findPathTo(parser, terminal)!;
expect(path.source, parser);
expect(path.target, terminal);
expect(path.parsers, [parser, terminal]);
expect(path.indexes, [0]);
final paths = analyzer.findAllPathsTo(parser, terminal).toList();
expect(paths, hasLength(2));
expect(paths[0].parsers, [parser, terminal]);
expect(paths[0].indexes, [0]);
expect(paths[1].parsers, [parser, terminal]);
expect(paths[1].indexes, [1]);
});
test('length', () {
final terminal = char('a');
final repeated = terminal.star();
final parser = repeated | terminal;
final analyzer = Analyzer(parser);
final path = analyzer.findPathTo(parser, terminal)!;
expect(path.source, parser);
expect(path.target, terminal);
expect(path.parsers, [parser, terminal]);
expect(path.indexes, [1]);
final paths = analyzer.findAllPathsTo(parser, terminal).toList();
expect(paths, hasLength(2));
expect(paths[0].parsers, [parser, repeated, terminal]);
expect(paths[0].indexes, [0, 0]);
expect(paths[1].parsers, [parser, terminal]);
expect(paths[1].indexes, [1]);
});
test('recursive grammar', () {
final parsers = createRecursive();
final analyzer = Analyzer(parsers[#S]!);
expect(
analyzer.findAllPaths(analyzer.root, (target) => false), isEmpty);
});
test('self reference', () {
final parser = createSelfReference();
final analyzer = Analyzer(parser);
expect(
analyzer.findAllPaths(analyzer.root, (target) => false), isEmpty);
});
});
group('isNullable', () {
test('plus', () {
final parser = char('a').plus();
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isFalse);
});
test('star', () {
final parser = char('a').star();
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isTrue);
});
test('optional', () {
final parser = char('a').optional();
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isTrue);
});
test('choice', () {
final parser = char('a').or(char('b'));
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isFalse);
});
test('epsilon choice', () {
final parser = char('a').or(epsilon());
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isTrue);
});
test('sequence', () {
final parser = char('a').seq(char('b'));
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isFalse);
});
test('epsilon sequence', () {
final parser = epsilon().seq(char('a'));
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isFalse);
});
test('optional sequence', () {
final parser = char('a').optional().seq(char('b'));
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isFalse);
});
test('übersetzerbau grammar', () {
final parsers = createUebersetzerbau();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.isNullable(parsers[#S]!), isFalse);
expect(analyzer.isNullable(parsers[#A]!), isTrue);
expect(analyzer.isNullable(parsers[#B]!), isTrue);
expect(analyzer.isNullable(parsers[#a]!), isFalse);
expect(analyzer.isNullable(parsers[#b]!), isFalse);
expect(analyzer.isNullable(parsers[#c]!), isFalse);
expect(analyzer.isNullable(parsers[#d]!), isFalse);
expect(analyzer.isNullable(parsers[#e]!), isTrue);
});
test('dragon grammar', () {
final parsers = createDragon();
final analyzer = Analyzer(parsers[#E]!);
expect(analyzer.isNullable(parsers[#E]!), isFalse);
expect(analyzer.isNullable(parsers[#Ep]!), isTrue);
expect(analyzer.isNullable(parsers[#T]!), isFalse);
expect(analyzer.isNullable(parsers[#Tp]!), isTrue);
expect(analyzer.isNullable(parsers[#F]!), isFalse);
});
test('ambiguous grammar', () {
final parsers = createAmbiguous();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.isNullable(parsers[#S]!), isFalse);
expect(analyzer.isNullable(parsers[#A]!), isFalse);
expect(analyzer.isNullable(parsers[#B]!), isFalse);
expect(analyzer.isNullable(parsers[#a]!), isFalse);
expect(analyzer.isNullable(parsers[#b]!), isFalse);
});
test('recursive grammar', () {
final parsers = createRecursive();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.isNullable(parsers[#S]!), isFalse);
expect(analyzer.isNullable(parsers[#P]!), isFalse);
expect(analyzer.isNullable(parsers[#p]!), isFalse);
});
test('self reference', () {
final parser = createSelfReference();
final analyzer = Analyzer(parser);
expect(analyzer.isNullable(parser), isFalse);
});
});
group('first-set', () {
test('plus', () {
final parser = char('a').plus();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a']);
});
test('star', () {
final parser = char('a').star();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a', '']);
});
test('optional', () {
final parser = char('a').optional();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a', '']);
});
test('choice', () {
final parser = char('a').or(char('b'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a', 'b']);
});
test('epsilon choice', () {
final parser = char('a').or(epsilon());
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a', '']);
});
test('sequence', () {
final parser = char('a').seq(char('b'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a']);
});
test('epsilon sequence', () {
final parser = epsilon().seq(char('a'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a']);
});
test('optional sequence', () {
final parser = char('a').optional().seq(char('b'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), ['a', 'b']);
});
test('übersetzerbau grammar', () {
final parsers = createUebersetzerbau();
final analyzer = Analyzer(parsers[#S]!);
expectTerminals(analyzer.firstSet(parsers[#S]!), ['a', 'b', 'c']);
expectTerminals(analyzer.firstSet(parsers[#A]!), ['a', 'b', '']);
expectTerminals(analyzer.firstSet(parsers[#B]!), ['b', '']);
expectTerminals(analyzer.firstSet(parsers[#a]!), ['a']);
expectTerminals(analyzer.firstSet(parsers[#b]!), ['b']);
expectTerminals(analyzer.firstSet(parsers[#c]!), ['c']);
expectTerminals(analyzer.firstSet(parsers[#d]!), ['d']);
expectTerminals(analyzer.firstSet(parsers[#e]!), ['']);
});
test('dragon grammar', () {
final parsers = createDragon();
final analyzer = Analyzer(parsers[#E]!);
expectTerminals(analyzer.firstSet(parsers[#E]!), ['(', 'i']);
expectTerminals(analyzer.firstSet(parsers[#Ep]!), ['+', '']);
expectTerminals(analyzer.firstSet(parsers[#T]!), ['(', 'i']);
expectTerminals(analyzer.firstSet(parsers[#Tp]!), ['*', '']);
expectTerminals(analyzer.firstSet(parsers[#F]!), ['(', 'i']);
});
test('ambiguous grammar', () {
final parsers = createAmbiguous();
final analyzer = Analyzer(parsers[#S]!);
expectTerminals(analyzer.firstSet(parsers[#S]!), ['a', 'b']);
expectTerminals(analyzer.firstSet(parsers[#A]!), ['a', 'b']);
expectTerminals(analyzer.firstSet(parsers[#B]!), ['a']);
expectTerminals(analyzer.firstSet(parsers[#a]!), ['a']);
expectTerminals(analyzer.firstSet(parsers[#b]!), ['b']);
});
test('recursive grammar', () {
final parsers = createRecursive();
final analyzer = Analyzer(parsers[#S]!);
expectTerminals(analyzer.firstSet(parsers[#S]!), ['p']);
expectTerminals(analyzer.firstSet(parsers[#P]!), ['p']);
expectTerminals(analyzer.firstSet(parsers[#p]!), ['p']);
});
test('self reference', () {
final parser = createSelfReference();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.firstSet(parser), []);
});
});
group('follow-set', () {
test('plus', () {
final parser = char('a').plus();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['a', '']);
});
test('star', () {
final parser = char('a').star();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['a', '']);
});
test('optional', () {
final parser = char('a').optional();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['']);
});
test('choice', () {
final parser = char('a').or(char('b'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['']);
expectTerminals(analyzer.followSet(parser.children[1]), ['']);
});
test('epsilon choice', () {
final parser = char('a').or(epsilon());
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['']);
expectTerminals(analyzer.followSet(parser.children[1]), ['']);
});
test('sequence', () {
final parser = char('a').seq(char('b'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['b']);
expectTerminals(analyzer.followSet(parser.children[1]), ['']);
});
test('epsilon sequence', () {
final parser = epsilon().seq(char('a'));
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['a']);
expectTerminals(analyzer.followSet(parser.children[1]), ['']);
});
test('optional sequence', () {
final parser = char('a').seq(char('b').optional());
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
expectTerminals(analyzer.followSet(parser.children[0]), ['b', '']);
expectTerminals(analyzer.followSet(parser.children[1]), ['']);
});
test('übersetzerbau grammar', () {
final parsers = createUebersetzerbau();
final analyzer = Analyzer(parsers[#S]!);
expectTerminals(analyzer.followSet(parsers[#S]!), ['']);
expectTerminals(analyzer.followSet(parsers[#A]!), ['b', 'c']);
expectTerminals(analyzer.followSet(parsers[#B]!), ['b', 'c']);
expectTerminals(analyzer.followSet(parsers[#a]!), ['b', 'c']);
expectTerminals(analyzer.followSet(parsers[#b]!), ['b', 'c']);
expectTerminals(analyzer.followSet(parsers[#c]!), ['d']);
expectTerminals(analyzer.followSet(parsers[#d]!), ['']);
expectTerminals(analyzer.followSet(parsers[#e]!), ['b', 'c']);
});
test('dragon grammar', () {
final parsers = createDragon();
final analyzer = Analyzer(parsers[#E]!);
expectTerminals(analyzer.followSet(parsers[#E]!), [')', '']);
expectTerminals(analyzer.followSet(parsers[#Ep]!), [')', '']);
expectTerminals(analyzer.followSet(parsers[#T]!), [')', '+', '']);
expectTerminals(analyzer.followSet(parsers[#Tp]!), [')', '+', '']);
expectTerminals(analyzer.followSet(parsers[#F]!), [')', '+', '*', '']);
});
test('ambiguous grammar', () {
final parsers = createAmbiguous();
final analyzer = Analyzer(parsers[#S]!);
expectTerminals(analyzer.followSet(parsers[#S]!), ['a', '']);
expectTerminals(analyzer.followSet(parsers[#A]!), ['a', 'b', '']);
expectTerminals(analyzer.followSet(parsers[#B]!), ['a', 'b', '']);
expectTerminals(analyzer.followSet(parsers[#a]!), ['a', 'b', '']);
expectTerminals(analyzer.followSet(parsers[#b]!), ['a', 'b', '']);
});
test('recursive grammar', () {
final parsers = createRecursive();
final analyzer = Analyzer(parsers[#S]!);
expectTerminals(analyzer.followSet(parsers[#S]!), ['+', '']);
expectTerminals(analyzer.followSet(parsers[#P]!), ['+', '']);
expectTerminals(analyzer.followSet(parsers[#p]!), ['+', '']);
});
test('self reference', () {
final parser = createSelfReference();
final analyzer = Analyzer(parser);
expectTerminals(analyzer.followSet(parser), ['']);
});
});
group('cycle-set', () {
test('übersetzerbau grammar', () {
final parsers = createUebersetzerbau();
final analyzer = Analyzer(parsers[#S]!);
for (final parser in parsers.values) {
expect(analyzer.cycleSet(parser), isEmpty);
}
});
test('dragon grammar', () {
final parsers = createDragon();
final analyzer = Analyzer(parsers[#E]!);
for (final parser in parsers.values) {
expect(analyzer.cycleSet(parser), isEmpty);
}
});
test('ambiguous grammar', () {
final parsers = createAmbiguous();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.cycleSet(parsers[#S]!),
allOf(hasLength(6), containsAll([parsers[#S], parsers[#A]])));
expect(analyzer.cycleSet(parsers[#A]!),
allOf(hasLength(6), containsAll([parsers[#S], parsers[#A]])));
expect(analyzer.cycleSet(parsers[#B]!),
allOf(hasLength(3), containsAll([parsers[#B]])));
expect(analyzer.cycleSet(parsers[#a]!), isEmpty);
expect(analyzer.cycleSet(parsers[#b]!), isEmpty);
});
test('recursive grammar', () {
final parsers = createRecursive();
final analyzer = Analyzer(parsers[#S]!);
expect(analyzer.cycleSet(parsers[#S]!),
allOf(hasLength(4), containsAll([parsers[#S], parsers[#P]])));
expect(analyzer.cycleSet(parsers[#P]!),
allOf(hasLength(4), containsAll([parsers[#S], parsers[#P]])));
expect(analyzer.cycleSet(parsers[#p]!), isEmpty);
});
test('self reference', () {
final parser = createSelfReference();
final analyzer = Analyzer(parser);
expect(analyzer.cycleSet(parser),
allOf(hasLength(1), containsAll([parser])));
});
});
});
group('iterable', () {
test('single', () {
final parser1 = lowercase();
final parsers = allParser(parser1).toList();
expect(parsers, [parser1]);
});
test('nested', () {
final parser3 = lowercase();
final parser2 = parser3.star();
final parser1 = parser2.flatten();
final parsers = allParser(parser1).toList();
expect(parsers, [parser1, parser2, parser3]);
});
test('branched', () {
final parser3 = lowercase();
final parser2 = uppercase();
final parser1 = parser2.seq(parser3);
final parsers = allParser(parser1).toList();
expect(parsers, [parser1, parser2, parser3]);
});
test('duplicated', () {
final parser2 = uppercase();
final parser1 = parser2.seq(parser2);
final parsers = allParser(parser1).toList();
expect(parsers, [parser1, parser2]);
});
test('knot', () {
final parser1 = undefined<void>();
parser1.set(parser1);
final parsers = allParser(parser1).toList();
expect(parsers, [parser1]);
});
test('looping', () {
final parser1 = undefined<void>();
final parser2 = undefined<void>();
final parser3 = undefined<void>();
parser1.set(parser2);
parser2.set(parser3);
parser3.set(parser1);
final parsers = allParser(parser1).toList();
expect(parsers, [parser1, parser2, parser3]);
});
});
group('linter', () {
test('rules called on all parsers', () {
final seen = <Parser>{};
final input = char('a') | char('b');
final rule = PluggableLinterRule(LinterType.error, 'Fake Rule',
(rule, analyzer, parser, callback) => seen.add(parser));
final results = linter(input,
rules: [rule], callback: (issue) => fail('Unexpected callback'));
expect(results, isEmpty);
expect(seen, {input, input.children[0], input.children[1]});
});
test('issue triggered', () {
final input = 'trigger'.toParser();
final called = <LinterIssue>[];
final rule = PluggableLinterRule(LinterType.error, 'Fake Rule',
(rule, analyzer, parser, callback) {
expect(parser, same(input));
callback(LinterIssue(rule, parser, 'Described'));
});
expect(
rule,
isLinterRule(
type: LinterType.error,
title: 'Fake Rule',
toString:
'LinterRule(type: LinterType.error, title: Fake Rule)'));
final results = linter(input, rules: [rule], callback: called.add);
expect(results, [
isLinterIssue(
rule: same(rule),
type: LinterType.error,
title: 'Fake Rule',
parser: same(input),
description: 'Described',
toString: 'LinterIssue(type: LinterType.error, title: Fake Rule, '
'parser: PredicateParser["trigger" expected], description: '
'Described)')
]);
expect(called, results);
});
group('rules', () {
group('character repetition', () {
const rules = [linter_rules.CharacterRepeater()];
test('with character predicate parser', () {
final parser = char('a').star().flatten();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.warning,
title: 'Character repeater')
]);
});
test('with any parser', () {
final parser = any().plus().flatten();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.warning,
title: 'Character repeater')
]);
});
test('without issue', () {
final parser = char('a').plus().token();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('left recursion', () {
const rules = [linter_rules.LeftRecursion()];
test('with issue', () {
final parser = createSelfReference();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser.children[0],
type: LinterType.error,
title: 'Left recursion')
]);
});
test('without issue', () {
final parser = digit();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('nested choice', () {
const rules = [linter_rules.NestedChoice()];
test('with issue', () {
final parser = [
char('1'),
[char('2'), char('3')].toChoiceParser(),
char('4'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser, type: LinterType.info, title: 'Nested choice')
]);
});
test('without issue', () {
final parser = [
char('1'),
[char('2'), char('3')].toChoiceParser().flatten(),
char('4'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('nullable repeater', () {
const rules = [linter_rules.NullableRepeater()];
test('with issue', () {
final parser = epsilon().star().optional();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser.children[0],
type: LinterType.error,
title: 'Nullable repeater')
]);
});
test('without issue', () {
final parser = digit().star().optional();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('overlapping choice', () {
const rules = [linter_rules.OverlappingChoice()];
test('with issue', () {
final parser = [
char('1'),
char('2') & char('a'),
char('2') & char('b'),
char('3'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.info,
title: 'Overlapping choice')
]);
});
test('without issue', () {
final parser = [
char('1'),
char('2'),
char('3'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('repeated choice', () {
const rules = [linter_rules.RepeatedChoice()];
test('with issue', () {
final parser = [
char('1'),
char('2'),
char('3'),
char('2'),
char('4'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.warning,
title: 'Repeated choice')
]);
});
test('without issue', () {
final parser = [
char('1'),
char('2'),
char('3'),
char('4'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('unnecessary flatten', () {
const rules = [linter_rules.UnnecessaryFlatten()];
test('with issue', () {
final parser = any().flatten();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.warning,
title: 'Unnecessary flatten')
]);
});
test('without issue', () {
final parser = any().optional().flatten();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('unnecessary resolvable', () {
const rules = [linter_rules.UnnecessaryResolvable()];
test('with issue', () {
final parser = char('a').settable();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.warning,
title: 'Unnecessary resolvable')
]);
});
test('without issue', () {
final parser = char('a');
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('unoptimized flatten', () {
const rules = [linter_rules.UnoptimizedFlatten()];
test('with issue', () {
final parser = any().flatten();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.info,
title: 'Unoptimized flatten')
]);
});
test('without issue', () {
final parser = any().flatten('anything really');
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('unreachable choice', () {
const rules = [linter_rules.UnreachableChoice()];
test('with issue', () {
final parser = [
char('1'),
char('2'),
epsilon(),
char('3'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.warning,
title: 'Unreachable choice')
]);
});
test('without issue', () {
final parser = [
char('1'),
char('2'),
char('3'),
].toChoiceParser();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('unresolved settable', () {
const rules = [linter_rules.UnresolvedSettable()];
test('with issue', () {
final parser = undefined<void>();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser,
type: LinterType.error,
title: 'Unresolved settable')
]);
});
test('without issue', () {
final parser = digit().settable();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
group('unused result', () {
const rules = [linter_rules.UnusedResult()];
test('with issue', () {
final parser = digit().map(int.parse).star().flatten();
final results = linter(parser, rules: rules);
expect(results, [
isLinterIssue(
parser: parser, type: LinterType.info, title: 'Unused result')
]);
});
test('without issue', () {
final parser = digit().star().flatten();
final results = linter(parser, rules: rules);
expect(results, isEmpty);
});
});
});
group('regressions', () {
test('separatedBy and nullable repeater', () {
const rules = [linter_rules.NullableRepeater()];
// Both repeater and separator are nullable, this might cause an
// infinite loop.
expect(linter(epsilon().starSeparated(epsilon()), rules: rules),
[isLinterIssue(title: 'Nullable repeater')]);
// If either the repeater or the separator is non-nullable, everything
// is fine.
expect(linter(epsilon().starSeparated(any()), rules: rules), isEmpty);
expect(linter(any().starSeparated(epsilon()), rules: rules), isEmpty);
});
});
});
group('transform', () {
test('copy', () {
final input = lowercase().settable();
final output = transformParser(input, <T>(parser) => parser);
expect(input, isNot(output));
expect(input.isEqualTo(output), isTrue);
expect(input.children.single, isNot(output.children.single));
});
test('root', () {
final source = lowercase();
final input = source;
final target = uppercase();
final output = transformParser(
input,
<T>(parser) =>
source.isEqualTo(parser) ? target as Parser<T> : parser);
expect(input, isNot(output));
expect(input.isEqualTo(output), isFalse);
expect(input, source);
expect(output, target);
});
test('single', () {
final source = lowercase();
final input = source.settable();
final target = uppercase();
final output = transformParser(
input,
<T>(parser) =>
source.isEqualTo(parser) ? target as Parser<T> : parser);
expect(input, isNot(output));
expect(input.isEqualTo(output), isFalse);
expect(input.children.single, source);
expect(output.children.single, target);
});
test('double', () {
final source = lowercase();
final input = source & source;
final target = uppercase();
final output = transformParser(
input,
<T>(parser) =>
source.isEqualTo(parser) ? target as Parser<T> : parser);
expect(input, isNot(output));
expect(input.isEqualTo(output), isFalse);
expect(input.isEqualTo(source & source), isTrue);
expect(input.children.first, input.children.last);
expect(output.isEqualTo(target & target), isTrue);
expect(output.children.first, output.children.last);
});
test('loop (existing)', () {
final inner = failure<void>().settable();
final outer = inner.settable().settable();
inner.set(outer);
final output = transformParser(outer, <T>(parser) => parser);
expect(outer, isNot(output));
expect(outer.isEqualTo(output), isTrue);
final inputs = allParser(outer).toSet();
final outputs = allParser(output).toSet();
for (final input in inputs) {
expect(outputs.contains(input), isFalse);
}
for (final output in outputs) {
expect(inputs.contains(output), isFalse);
}
});
test('loop (new)', () {
final source = lowercase();
final input = source;
final inner = failure<String>().settable();
final outer = inner.settable().settable();
inner.set(outer);
final output = transformParser(
input,
<T>(parser) =>