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pegjs/spec/generated-parser.spec.js

954 lines
31 KiB
JavaScript

describe("generated parser", function() {
function vary(names, block) {
var values = {
trackLineAndColumn: [false, true],
cache: [false, true]
};
function varyStep(names, options) {
var clonedOptions = {}, key, name, i;
if (names.length === 0) {
/*
* We have to clone the options so that the block can save them safely
* (e.g. by capturing in a closure) without the risk that they will be
* changed later.
*/
for (key in options) {
clonedOptions[key] = options[key];
}
describe(
"with options " + jasmine.pp(clonedOptions),
function() { block(clonedOptions); }
);
} else {
name = names[0];
for (i = 0; i < values[name].length; i++) {
options[name] = values[name][i];
varyStep(names.slice(1), options);
}
}
}
varyStep(names, {});
}
function varyAll(block) {
vary(["cache", "trackLineAndColumn"], block);
}
beforeEach(function() {
this.addMatchers({
toParse: function(input, expected) {
var result;
try {
result = this.actual.parse(input);
this.message = function() {
return "Expected " + jasmine.pp(input) + " "
+ (this.isNot ? "not " : "")
+ "to parse as " + jasmine.pp(expected) + ", "
+ "but it parsed as " + jasmine.pp(result) + ".";
};
return this.env.equals_(result, expected);
} catch (e) {
this.message = function() {
return "Expected " + jasmine.pp(input) + " "
+ "to parse as " + jasmine.pp(expected) + ", "
+ "but it failed to parse with message "
+ jasmine.pp(e.message) + ".";
};
return false;
}
},
toFailToParse: function(input, details) {
/*
* Extracted into a function just to silence JSHint complaining about
* creating functions in a loop.
*/
function buildKeyMessage(key, value) {
return function() {
return "Expected " + jasmine.pp(input) + " to fail to parse"
+ (details ? " with details " + jasmine.pp(details) : "") + ", "
+ "but " + jasmine.pp(key) + " "
+ "is " + jasmine.pp(value) + ".";
};
}
var result, key;
try {
result = this.actual.parse(input);
this.message = function() {
return "Expected " + jasmine.pp(input) + " to fail to parse"
+ (details ? " with details " + jasmine.pp(details) : "") + ", "
+ "but it parsed as " + jasmine.pp(result) + ".";
};
return false;
} catch (e) {
if (this.isNot) {
this.message = function() {
return "Expected " + jasmine.pp(input) + " to parse, "
+ "but it failed with message "
+ jasmine.pp(e.message) + ".";
};
} else {
if (details) {
for (key in details) {
if (!this.env.equals_(e[key], details[key])) {
this.message = buildKeyMessage(key, e[key]);
return false;
}
}
}
}
return true;
}
}
});
});
describe("parse", function() {
var parser = PEG.buildParser([
'a = "x" { return "a"; }',
'b = "x" { return "b"; }'
].join("\n"));
it("uses the fist rule as a start rule when no |startRule| is specified", function() {
expect(parser.parse("x")).toBe("a");
});
it("uses the specified rule as a start rule when |startRule| is specified", function() {
expect(parser.parse("x", "a")).toBe("a");
expect(parser.parse("x", "b")).toBe("b");
});
it("throws exception when the specified start rule does not exist", function() {
expect(function() {
parser.parse("x", "c");
}).toThrow("Invalid rule name: \"c\".");
});
});
varyAll(function(options) {
describe("initializer code", function() {
it("runs before the parsing begins", function() {
var parser = PEG.buildParser([
'{ var result = 42; }',
'start = "a" { return result }'
].join("\n"), options);
expect(parser).toParse("a", 42);
});
});
describe("rule matching", function() {
var grammar = [
'{ var n = 0; }',
'start = (a "b") / (a "c") { return n; }',
'a = "a" { n++; }'
].join("\n");
if (options.cache) {
it("caches rule match results", function() {
var parser = PEG.buildParser(grammar, options);
expect(parser).toParse("ac", 1);
});
} else {
it("does not cache rule match results", function() {
var parser = PEG.buildParser(grammar, options);
expect(parser).toParse("ac", 2);
});
}
it("does not overwrite expected string on failure when not named", function() {
var parser = PEG.buildParser('start = [0-9]', options);
expect(parser).toFailToParse("a", { expected: ["[0-9]"] });
});
it("overwrites expected string on failure when named", function() {
var parser = PEG.buildParser('start "digit" = [0-9]', options);
expect(parser).toFailToParse("a", { expected: ["digit"] });
});
});
describe("choice matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = "a" / "b" / "c"', options);
expect(parser).toParse("a", "a");
expect(parser).toParse("b", "b");
expect(parser).toParse("c", "c");
expect(parser).toFailToParse("d");
});
});
describe("sequence matching", function() {
it("matches empty sequence correctly", function() {
var parser = PEG.buildParser('start = ', options);
expect(parser).toParse("", []);
});
it("matches non-empty sequence correctly", function() {
var parser = PEG.buildParser('start = "a" "b" "c"', options);
expect(parser).toParse("abc", ["a", "b", "c"]);
});
it("does not advance position on failure", function() {
var parser = PEG.buildParser('start = "a" "b" / "a"', options);
expect(parser).toParse("a", "a");
});
});
describe("labeled matching", function() {
it("delegates to the expression", function() {
var parser = PEG.buildParser('start = a:"a"', options);
expect(parser).toParse("a", "a");
expect(parser).toFailToParse("b");
});
});
describe("simple and matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = &"a" "a"', options);
expect(parser).toParse("a", ["", "a"]);
expect(parser).toFailToParse("b");
});
it("does not advance position on success", function() {
var parser = PEG.buildParser('start = &"a" "a"', options);
expect(parser).toParse("a", ["", "a"]);
});
it("does not influence expected strings on failure", function() {
var parser = PEG.buildParser('start = &"a"', options);
expect(parser).toFailToParse("b", { expected: [] });
});
});
describe("simple not matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = !"a" "b"', options);
expect(parser).toParse("b", ["", "b"]);
expect(parser).toFailToParse("a");
});
it("does not advance position on failure", function() {
var parser = PEG.buildParser('start = !"a" / "a"', options);
expect(parser).toParse("a", "a");
});
it("does not influence expected strings on failure", function() {
var parser = PEG.buildParser('start = !"a"', options);
expect(parser).toFailToParse("a", { expected: [] });
});
});
describe("semantic and code", function() {
it("causes successful match by returning |true|", function() {
var parser = PEG.buildParser('start = &{ return true; }', options);
expect(parser).toParse("", "");
});
it("causes match failure by returning |false|", function() {
var parser = PEG.buildParser('start = &{ return false; }', options);
expect(parser).toFailToParse("");
});
it("can use label variables", function() {
var parser = PEG.buildParser(
'start = a:"a" &{ return a === "a"; }',
options
);
expect(parser).toParse("a", ["a", ""]);
});
it("can use the |offset| variable to get the current parse position", function() {
var parser = PEG.buildParser(
'start = "a" &{ return offset === 1; }',
options
);
expect(parser).toParse("a", ["a", ""]);
});
if (options.trackLineAndColumn) {
it("can use the |line| and |column| variables to get the current line and column", function() {
var parser = PEG.buildParser([
'{ var result; }',
'start = line (nl+ line)* { return result; }',
'line = thing (" "+ thing)*',
'thing = digit / mark',
'digit = [0-9]',
'mark = &{ result = [line, column]; return true; } "x"',
'nl = ("\\r" / "\\n" / "\\u2028" / "\\u2029")'
].join("\n"), options);
expect(parser).toParse("1\n2\n\n3\n\n\n4 5 x", [7, 5]);
/* Non-Unix newlines */
expect(parser).toParse("1\rx", [2, 1]); // Old Mac
expect(parser).toParse("1\r\nx", [2, 1]); // Windows
expect(parser).toParse("1\n\rx", [3, 1]); // mismatched
/* Strange newlines */
expect(parser).toParse("1\u2028x", [2, 1]); // line separator
expect(parser).toParse("1\u2029x", [2, 1]); // paragraph separator
});
}
it("can use variables defined in the initializer", function() {
var parser = PEG.buildParser([
'{ var v = 42 }',
'start = "a" &{ return v === 42; }'
].join("\n"), options);
expect(parser).toParse("a", ["a", ""]);
});
it("can use functions defined in the initializer", function() {
var parser = PEG.buildParser([
'{ function f() { return 42; } }',
'start = "a" &{ return f() === 42; }'
].join("\n"), options);
expect(parser).toParse("a", ["a", ""]);
});
});
describe("semantic not code", function() {
it("causes successful match by returning |false|", function() {
var parser = PEG.buildParser('start = !{ return false; }', options);
expect(parser).toParse("", "");
});
it("causes match failure by returning |true|", function() {
var parser = PEG.buildParser('start = !{ return true; }', options);
expect(parser).toFailToParse();
});
it("can use label variables", function() {
var parser = PEG.buildParser(
'start = a:"a" !{ return a !== "a"; }',
options
);
expect(parser).toParse("a", ["a", ""]);
});
it("can use the |offset| variable to get the current parse position", function() {
var parser = PEG.buildParser(
'start = "a" !{ return offset !== 1; }',
options
);
expect(parser).toParse("a", ["a", ""]);
});
if (options.trackLineAndColumn) {
it("can use the |line| and |column| variables to get the current line and column", function() {
var parser = PEG.buildParser([
'{ var result; }',
'start = line (nl+ line)* { return result; }',
'line = thing (" "+ thing)*',
'thing = digit / mark',
'digit = [0-9]',
'mark = !{ result = [line, column]; return false; } "x"',
'nl = ("\\r" / "\\n" / "\\u2028" / "\\u2029")'
].join("\n"), options);
expect(parser).toParse("1\n2\n\n3\n\n\n4 5 x", [7, 5]);
/* Non-Unix newlines */
expect(parser).toParse("1\rx", [2, 1]); // Old Mac
expect(parser).toParse("1\r\nx", [2, 1]); // Windows
expect(parser).toParse("1\n\rx", [3, 1]); // mismatched
/* Strange newlines */
expect(parser).toParse("1\u2028x", [2, 1]); // line separator
expect(parser).toParse("1\u2029x", [2, 1]); // paragraph separator
});
}
it("can use variables defined in the initializer", function() {
var parser = PEG.buildParser([
'{ var v = 42 }',
'start = "a" !{ return v !== 42; }'
].join("\n"), options);
expect(parser).toParse("a", ["a", ""]);
});
it("can use functions defined in the initializer", function() {
var parser = PEG.buildParser([
'{ function f() { return 42; } }',
'start = "a" !{ return f() !== 42; }'
].join("\n"), options);
expect(parser).toParse("a", ["a", ""]);
});
});
describe("optional matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = "a"?', options);
expect(parser).toParse("", "");
expect(parser).toParse("a", "a");
});
});
describe("zero or more matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = "a"*', options);
expect(parser).toParse("", []);
expect(parser).toParse("a", ["a"]);
expect(parser).toParse("aaa", ["a", "a", "a"]);
});
});
describe("one or more matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = "a"+', options);
expect(parser).toFailToParse("");
expect(parser).toParse("a", ["a"]);
expect(parser).toParse("aaa", ["a", "a", "a"]);
});
});
describe("action code", function() {
it("tranforms the expression result by returnung a non-|null| value", function() {
var parser = PEG.buildParser('start = "a" { return 42; }', options);
expect(parser).toParse("a", 42);
});
it("causes match failure by returning |null|", function() {
var parser = PEG.buildParser('start = "a" { return null; }', options);
expect(parser).toFailToParse("a");
});
it("is not called when the expression does not match", function() {
var parser = PEG.buildParser(
'start = "a" { throw "Boom!"; } / "b"',
options
);
expect(parser).toParse("b", "b");
});
it("can use label variables", function() {
var parser = PEG.buildParser('start = a:"a" { return a; }', options);
expect(parser).toParse("a", "a");
});
it("can use the |offset| variable to get the current parse position", function() {
var parser = PEG.buildParser(
'start = "a" ("b" { return offset; })',
options
);
expect(parser).toParse("ab", ["a", 1]);
});
if (options.trackLineAndColumn) {
it("can use the |line| and |column| variables to get the current line and column", function() {
var parser = PEG.buildParser([
'{ var result; }',
'start = line (nl+ line)* { return result; }',
'line = thing (" "+ thing)*',
'thing = digit / mark',
'digit = [0-9]',
'mark = "x" { result = [line, column]; }',
'nl = ("\\r" / "\\n" / "\\u2028" / "\\u2029")'
].join("\n"), options);
expect(parser).toParse("1\n2\n\n3\n\n\n4 5 x", [7, 5]);
/* Non-Unix newlines */
expect(parser).toParse("1\rx", [2, 1]); // Old Mac
expect(parser).toParse("1\r\nx", [2, 1]); // Windows
expect(parser).toParse("1\n\rx", [3, 1]); // mismatched
/* Strange newlines */
expect(parser).toParse("1\u2028x", [2, 1]); // line separator
expect(parser).toParse("1\u2029x", [2, 1]); // paragraph separator
});
}
it("can use variables defined in the initializer", function() {
var parser = PEG.buildParser([
'{ var v = 42 }',
'start = "a" { return v; }'
].join("\n"), options);
expect(parser).toParse("a", 42);
});
it("can use functions defined in the initializer", function() {
var parser = PEG.buildParser([
'{ function f() { return 42; } }',
'start = "a" { return f(); }'
].join("\n"), options);
expect(parser).toParse("a", 42);
});
it("does not advance position when the expression matches but the action returns |null|", function() {
var parser = PEG.buildParser(
'start = "a" { return null; } / "a"',
options
);
expect(parser).toParse("a", "a");
});
});
describe("rule reference matching", function() {
it("follows rule references", function() {
var parser = PEG.buildParser([
'start = static / dynamic',
'static = "C" / "C++" / "Java" / "C#"',
'dynamic = "Ruby" / "Python" / "JavaScript"'
].join("\n"), options);
expect(parser).toParse("Java", "Java");
expect(parser).toParse("Python", "Python");
});
});
describe("literal matching", function() {
it("matches empty literal correctly", function() {
var parser = PEG.buildParser('start = ""', options);
expect(parser).toParse("", "");
});
it("matches one-character literal correctly", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toParse("a", "a");
expect(parser).toFailToParse("b");
});
it("matches multiple-character literal correctly", function() {
var parser = PEG.buildParser('start = "abcd"', options);
expect(parser).toParse("abcd", "abcd");
expect(parser).toFailToParse("ebcd");
expect(parser).toFailToParse("afcd");
expect(parser).toFailToParse("abgd");
expect(parser).toFailToParse("abch");
});
it("is case sensitive without the \"i\" flag", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toParse("a", "a");
expect(parser).toFailToParse("A");
});
it("is case insensitive with the \"i\" flag", function() {
var parser = PEG.buildParser('start = "a"i', options);
expect(parser).toParse("a", "a");
expect(parser).toParse("A", "A");
});
it("advances position on success", function() {
var parser = PEG.buildParser('start = "a" .', options);
expect(parser).toParse("ab", ["a", "b"]);
});
it("sets expected string correctly on failure", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("b", { expected: ['"a"'] });
});
});
describe("any matching", function() {
it("matches correctly", function() {
var parser = PEG.buildParser('start = .', options);
expect(parser).toParse("a", "a");
});
it("advances position on success", function() {
var parser = PEG.buildParser('start = . .', options);
expect(parser).toParse("ab", ["a", "b"]);
});
it("sets expected string correctly on failure", function() {
var parser = PEG.buildParser('start = .', options);
expect(parser).toFailToParse("", { expected: ['any character'] });
});
});
describe("class matching", function() {
it("matches empty class correctly", function() {
var parser = PEG.buildParser('start = []', options);
expect(parser).toFailToParse("a");
});
it("matches class with a character list correctly", function() {
var parser = PEG.buildParser('start = [abc]', options);
expect(parser).toParse("a", "a");
expect(parser).toParse("b", "b");
expect(parser).toParse("c", "c");
expect(parser).toFailToParse("d");
});
it("matches class with a range correctly", function() {
var parser = PEG.buildParser('start = [a-c]', options);
expect(parser).toParse("a", "a");
expect(parser).toParse("b", "b");
expect(parser).toParse("c", "c");
expect(parser).toFailToParse("d");
});
it("matches inverted class correctly", function() {
var parser = PEG.buildParser('start = [^a]', options);
expect(parser).toFailToParse("a");
expect(parser).toParse("b", "b");
});
it("is case sensitive without the \"i\" flag", function() {
var parser = PEG.buildParser('start = [a]', options);
expect(parser).toParse("a", "a");
expect(parser).toFailToParse("A");
});
it("is case insensitive with the \"i\" flag", function() {
var parser = PEG.buildParser('start = [a]i', options);
expect(parser).toParse("a", "a");
expect(parser).toParse("A", "A");
});
it("advances position on success", function() {
var parser = PEG.buildParser('start = [a] .', options);
expect(parser).toParse("ab", ["a", "b"]);
});
it("sets expected string correctly on failure", function() {
var parser = PEG.buildParser('start = [a]', options);
expect(parser).toFailToParse("b", { expected: ["[a]"] });
});
});
describe("error reporting", function() {
describe("behavior", function() {
it("reports only the rightmost error", function() {
var parser = PEG.buildParser('start = "a" "b" / "a" "c" "d"', options);
expect(parser).toFailToParse("ace", { offset: 2, expected: ['"d"'] });
});
});
describe("expected strings reporting", function() {
it("reports expected strings correctly with no alternative", function() {
var parser = PEG.buildParser('start = ', options);
expect(parser).toFailToParse("a", { expected: [] });
});
it("reports expected strings correctly with one alternative", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("b", { expected: ['"a"'] });
});
it("reports expected strings correctly with multiple alternatives", function() {
var parser = PEG.buildParser('start = "a" / "b" / "c"', options);
expect(parser).toFailToParse("d", {
expected: ['"a"', '"b"', '"c"']
});
});
it("removes duplicates from expected strings", function() {
var parser = PEG.buildParser('start = "a" / "a"', options);
expect(parser).toFailToParse("b", { expected: ['"a"'] });
});
it("sorts expected strings", function() {
var parser = PEG.buildParser('start = "c" / "b" / "a"', options);
expect(parser).toFailToParse("d", {
expected: ['"a"', '"b"', '"c"']
});
});
});
describe("found string reporting", function() {
it("reports found string correctly at the end of input", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("", { found: null });
});
it("reports found string correctly in the middle of input", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("b", { found: "b" });
});
});
describe("message building", function() {
it("builds message correctly with no alternative", function() {
var parser = PEG.buildParser('start = ', options);
expect(parser).toFailToParse("a", {
message: 'Expected end of input but "a" found.'
});
});
it("builds message correctly with one alternative", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("b", {
message: 'Expected "a" but "b" found.'
});
});
it("builds message correctly with multiple alternatives", function() {
var parser = PEG.buildParser('start = "a" / "b" / "c"', options);
expect(parser).toFailToParse("d", {
message: 'Expected "a", "b" or "c" but "d" found.'
});
});
it("builds message correctly at the end of input", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("", {
message: 'Expected "a" but end of input found.'
});
});
it("builds message correctly in the middle of input", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("b", {
message: 'Expected "a" but "b" found.'
});
});
});
describe("position reporting", function() {
it("reports position correctly with invalid input", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("b", { offset: 0, line: 1, column: 1 });
});
it("reports position correctly with trailing input", function() {
var parser = PEG.buildParser('start = "a"', options);
expect(parser).toFailToParse("aa", { offset: 1, line: 1, column: 2});
});
it("reports position correctly in complex cases", function() {
var parser = PEG.buildParser([
'start = line (nl+ line)*',
'line = digit (" "+ digit)*',
'digit = [0-9]',
'nl = ("\\r" / "\\n" / "\\u2028" / "\\u2029")'
].join("\n"), options);
expect(parser).toFailToParse("1\n2\n\n3\n\n\n4 5 x", {
offset: 13,
line: 7,
column: 5
});
/* Non-Unix newlines */
expect(parser).toFailToParse("1\rx", { // Old Mac
offset: 2,
line: 2,
column: 1
});
expect(parser).toFailToParse("1\r\nx", { // Windows
offset: 3,
line: 2,
column: 1
});
expect(parser).toFailToParse("1\n\rx", { // mismatched
offset: 3,
line: 3,
column: 1
});
/* Strange newlines */
expect(parser).toFailToParse("1\u2028x", { // line separator
offset: 2,
line: 2,
column: 1
});
expect(parser).toFailToParse("1\u2029x", { // paragraph separator
offset: 2,
line: 2,
column: 1
});
});
});
});
/*
* Following examples are from Wikipedia, see
* http://en.wikipedia.org/w/index.php?title=Parsing_expression_grammar&oldid=335106938.
*/
describe("complex examples", function() {
it("handles arithmetics example correctly", function() {
/*
* Value ← [0-9]+ / '(' Expr ')'
* Product ← Value (('*' / '/') Value)*
* Sum ← Product (('+' / '-') Product)*
* Expr ← Sum
*/
var parser = PEG.buildParser([
'Expr = Sum',
'Sum = head:Product tail:(("+" / "-") Product)* {',
' var result = head, i;',
' for (i = 0; i < tail.length; i++) {',
' if (tail[i][0] == "+") { result += tail[i][1]; }',
' if (tail[i][0] == "-") { result -= tail[i][1]; }',
' }',
' return result;',
' }',
'Product = head:Value tail:(("*" / "/") Value)* {',
' var result = head, i;',
' for (i = 0; i < tail.length; i++) {',
' if (tail[i][0] == "*") { result *= tail[i][1]; }',
' if (tail[i][0] == "/") { result /= tail[i][1]; }',
' }',
' return result;',
' }',
'Value = digits:[0-9]+ { return parseInt(digits.join(""), 10); }',
' / "(" expr:Expr ")" { return expr; }'
].join("\n"), options);
/* The "value" rule */
expect(parser).toParse("0", 0);
expect(parser).toParse("123", 123);
expect(parser).toParse("(42+43)", 42+43);
/* The "product" rule */
expect(parser).toParse("42", 42);
expect(parser).toParse("42*43", 42*43);
expect(parser).toParse("42*43*44*45", 42*43*44*45);
expect(parser).toParse("42/43", 42/43);
expect(parser).toParse("42/43/44/45", 42/43/44/45);
/* The "sum" rule */
expect(parser).toParse("42*43", 42*43);
expect(parser).toParse("42*43+44*45", 42*43+44*45);
expect(parser).toParse("42*43+44*45+46*47+48*49", 42*43+44*45+46*47+48*49);
expect(parser).toParse("42*43-44*45", 42*43-44*45);
expect(parser).toParse("42*43-44*45-46*47-48*49", 42*43-44*45-46*47-48*49);
/* The "expr" rule */
expect(parser).toParse("42+43", 42+43);
/* Complex test */
expect(parser).toParse("(1+2)*(3+4)", (1+2)*(3+4));
});
it("handles non-context-free language correctly", function() {
/* The following parsing expression grammar describes the classic
* non-context-free language { a^n b^n c^n : n >= 1 }:
*
* S ← &(A c) a+ B !(a/b/c)
* A ← a A? b
* B ← b B? c
*/
var parser = PEG.buildParser([
'S = &(A "c") a:"a"+ B:B !("a" / "b" / "c") { return a.join("") + B; }',
'A = a:"a" A:A? b:"b" { return a + A + b; }',
'B = b:"b" B:B? c:"c" { return b + B + c; }'
].join("\n"), options);
expect(parser).toParse("abc", "abc");
expect(parser).toParse("aaabbbccc", "aaabbbccc");
expect(parser).toFailToParse("aabbbccc");
expect(parser).toFailToParse("aaaabbbccc");
expect(parser).toFailToParse("aaabbccc");
expect(parser).toFailToParse("aaabbbbccc");
expect(parser).toFailToParse("aaabbbcc");
expect(parser).toFailToParse("aaabbbcccc");
});
it("handles nested comments example correctly", function() {
/*
* Begin ← "(*"
* End ← "*)"
* C ← Begin N* End
* N ← C / (!Begin !End Z)
* Z ← any single character
*/
var parser = PEG.buildParser([
'C = begin:Begin ns:N* end:End { return begin + ns.join("") + end; }',
'N = C',
' / !Begin !End z:Z { return z; }',
'Z = .',
'Begin = "(*"',
'End = "*)"'
].join("\n"), options);
expect(parser).toParse("(**)", "(**)");
expect(parser).toParse("(*abc*)", "(*abc*)");
expect(parser).toParse("(*(**)*)", "(*(**)*)");
expect(parser).toParse(
"(*abc(*def*)ghi(*(*(*jkl*)*)*)mno*)",
"(*abc(*def*)ghi(*(*(*jkl*)*)*)mno*)"
);
});
});
});
});