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pegjs/spec/behavior/generated-parser-behavior.s...

1620 lines
54 KiB
JavaScript

/* global peg */
"use strict";
describe("generated parser behavior", function() {
function varyOptimizationOptions(block) {
function clone(object) {
var result = {}, key;
for (key in object) {
if (object.hasOwnProperty(key)) {
result[key] = object[key];
}
}
return result;
}
var optionsVariants = [
{ cache: false, optimize: "speed" },
{ cache: false, optimize: "size" },
{ cache: true, optimize: "speed" },
{ cache: true, optimize: "size" }
],
i;
for (i = 0; i < optionsVariants.length; i++) {
describe(
"with options " + jasmine.pp(optionsVariants[i]),
function() { block(clone(optionsVariants[i])); }
);
}
}
beforeEach(function() {
this.addMatchers({
toParse: function(input, expected, options) {
options = options !== undefined ? options : {};
var result;
try {
result = this.actual.parse(input, options);
if (expected !== undefined) {
this.message = function() {
return "Expected " + jasmine.pp(input) + " "
+ "with options " + jasmine.pp(options) + " "
+ (this.isNot ? "not " : "")
+ "to parse as " + jasmine.pp(expected) + ", "
+ "but it parsed as " + jasmine.pp(result) + ".";
};
return this.env.equals_(result, expected);
} else {
return true;
}
} catch (e) {
this.message = function() {
return "Expected " + jasmine.pp(input) + " "
+ "with options " + jasmine.pp(options) + " "
+ "to parse" + (expected !== undefined ? " as " + jasmine.pp(expected) : "") + ", "
+ "but it failed to parse with message "
+ jasmine.pp(e.message) + ".";
};
return false;
}
},
toFailToParse: function(input, details, options) {
options = options !== undefined ? options : {};
var result, key;
try {
result = this.actual.parse(input, options);
this.message = function() {
return "Expected " + jasmine.pp(input) + " "
+ "with options " + jasmine.pp(options) + " "
+ "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)
+ "with options " + jasmine.pp(options) + " "
+ "to parse, "
+ "but it failed with message "
+ jasmine.pp(e.message) + ".";
};
} else {
if (details) {
for (key in details) {
if (details.hasOwnProperty(key)) {
if (!this.env.equals_(e[key], details[key])) {
this.message = function() {
return "Expected " + jasmine.pp(input) + " "
+ "with options " + jasmine.pp(options) + " "
+ "to fail to parse"
+ (details ? " with details " + jasmine.pp(details) : "") + ", "
+ "but " + jasmine.pp(key) + " "
+ "is " + jasmine.pp(e[key]) + ".";
};
return false;
}
}
}
}
}
return true;
}
}
});
});
varyOptimizationOptions(function(options) {
describe("initializer", function() {
it("executes the code before parsing starts", function() {
var parser = peg.generate([
'{ var result = 42; }',
'start = "a" { return result; }'
].join("\n"), options);
expect(parser).toParse("a", 42);
});
describe("available variables and functions", function() {
it("|parser| contains the parser object", function() {
var parser = peg.generate([
'{ var result = parser; }',
'start = "a" { return result; }'
].join("\n"), options);
expect(parser).toParse("a", parser);
});
it("|options| contains options", function() {
var parser = peg.generate([
'{ var result = options; }',
'start = "a" { return result; }'
].join("\n"), options);
expect(parser).toParse("a", { a: 42 }, { a: 42 });
});
});
});
describe("rule", function() {
if (options.cache) {
it("caches rule match results", function() {
var parser = peg.generate([
'{ var n = 0; }',
'start = (a "b") / (a "c") { return n; }',
'a = "a" { n++; }'
].join("\n"), options);
expect(parser).toParse("ac", 1);
});
} else {
it("doesn't cache rule match results", function() {
var parser = peg.generate([
'{ var n = 0; }',
'start = (a "b") / (a "c") { return n; }',
'a = "a" { n++; }'
].join("\n"), options);
expect(parser).toParse("ac", 2);
});
}
describe("when the expression matches", function() {
it("returns its match result", function() {
var parser = peg.generate('start = "a"');
expect(parser).toParse("a", "a");
});
});
describe("when the expression doesn't match", function() {
describe("without display name", function() {
it("reports match failure and doesn't record any expectation", function() {
var parser = peg.generate('start = "a"');
expect(parser).toFailToParse("b", {
expected: [{ type: "literal", text: "a", ignoreCase: false }]
});
});
});
describe("with display name", function() {
it("reports match failure and records an expectation of type \"other\"", function() {
var parser = peg.generate('start "start" = "a"');
expect(parser).toFailToParse("b", {
expected: [{ type: "other", description: "start" }]
});
});
it("discards any expectations recorded when matching the expression", function() {
var parser = peg.generate('start "start" = "a"');
expect(parser).toFailToParse("b", {
expected: [{ type: "other", description: "start" }]
});
});
});
});
});
describe("literal", function() {
describe("matching", function() {
it("matches empty literals", function() {
var parser = peg.generate('start = ""', options);
expect(parser).toParse("");
});
it("matches one-character literals", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toParse("a");
expect(parser).toFailToParse("b");
});
it("matches multi-character literals", function() {
var parser = peg.generate('start = "abcd"', options);
expect(parser).toParse("abcd");
expect(parser).toFailToParse("efgh");
});
it("is case sensitive without the \"i\" flag", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toParse("a");
expect(parser).toFailToParse("A");
});
it("is case insensitive with the \"i\" flag", function() {
var parser = peg.generate('start = "a"i', options);
expect(parser).toParse("a");
expect(parser).toParse("A");
});
});
describe("when it matches", function() {
it("returns the matched text", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toParse("a", "a");
});
it("consumes the matched text", function() {
var parser = peg.generate('start = "a" .', options);
expect(parser).toParse("ab");
});
});
describe("when it doesn't match", function() {
it("reports match failure and records an expectation of type \"literal\"", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("b", {
expected: [{ type: "literal", text: "a", ignoreCase: false }]
});
});
});
});
describe("character class", function() {
describe("matching", function() {
it("matches empty classes", function() {
var parser = peg.generate('start = []', options);
expect(parser).toFailToParse("a");
});
it("matches classes with a character list", function() {
var parser = peg.generate('start = [abc]', options);
expect(parser).toParse("a");
expect(parser).toParse("b");
expect(parser).toParse("c");
expect(parser).toFailToParse("d");
});
it("matches classes with a character range", function() {
var parser = peg.generate('start = [a-c]', options);
expect(parser).toParse("a");
expect(parser).toParse("b");
expect(parser).toParse("c");
expect(parser).toFailToParse("d");
});
it("matches inverted classes", function() {
var parser = peg.generate('start = [^a]', options);
expect(parser).toFailToParse("a");
expect(parser).toParse("b");
});
it("is case sensitive without the \"i\" flag", function() {
var parser = peg.generate('start = [a]', options);
expect(parser).toParse("a");
expect(parser).toFailToParse("A");
});
it("is case insensitive with the \"i\" flag", function() {
var parser = peg.generate('start = [a]i', options);
expect(parser).toParse("a");
expect(parser).toParse("A");
});
});
describe("when it matches", function() {
it("returns the matched character", function() {
var parser = peg.generate('start = [a]', options);
expect(parser).toParse("a", "a");
});
it("consumes the matched character", function() {
var parser = peg.generate('start = [a] .', options);
expect(parser).toParse("ab");
});
});
describe("when it doesn't match", function() {
it("reports match failure and records an expectation of type \"class\"", function() {
var parser = peg.generate('start = [a]', options);
expect(parser).toFailToParse("b", {
expected: [{ type: "class", parts: ["a"], inverted: false, ignoreCase: false }]
});
});
});
});
describe("dot", function() {
describe("matching", function() {
it("matches any character", function() {
var parser = peg.generate('start = .', options);
expect(parser).toParse("a");
expect(parser).toParse("b");
expect(parser).toParse("c");
});
});
describe("when it matches", function() {
it("returns the matched character", function() {
var parser = peg.generate('start = .', options);
expect(parser).toParse("a", "a");
});
it("consumes the matched character", function() {
var parser = peg.generate('start = . .', options);
expect(parser).toParse("ab");
});
});
describe("when it doesn't match", function() {
it("reports match failure and records an expectation of type \"any\"", function() {
var parser = peg.generate('start = .', options);
expect(parser).toFailToParse("", {
expected: [{ type: "any" }]
});
});
});
});
describe("rule reference", function() {
describe("when referenced rule's expression matches", function() {
it("returns its result", function() {
var parser = peg.generate([
'start = a',
'a = "a"'
].join("\n"), options);
expect(parser).toParse("a", "a");
});
});
describe("when referenced rule's expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate([
'start = a',
'a = "a"'
].join("\n"), options);
expect(parser).toFailToParse("b");
});
});
});
describe("positive semantic predicate", function() {
describe("when the code returns a truthy value", function() {
it("returns |undefined|", function() {
/*
* The |""| is needed so that the parser doesn't return just
* |undefined| which we can't compare against in |toParse| due to the
* way optional parameters work.
*/
var parser = peg.generate('start = &{ return true; } ""', options);
expect(parser).toParse("", [undefined, ""]);
});
});
describe("when the code returns a falsey value", function() {
it("reports match failure", function() {
var parser = peg.generate('start = &{ return false; }', options);
expect(parser).toFailToParse("");
});
});
describe("label variables", function() {
describe("in containing sequence", function() {
it("can access variables defined by preceding labeled elements", function() {
var parser = peg.generate(
'start = a:"a" &{ return a === "a"; }',
options
);
expect(parser).toParse("a");
});
it("cannot access variable defined by labeled predicate element", function() {
var parser = peg.generate(
'start = "a" b:&{ return b === undefined; } "c"',
options
);
expect(parser).toFailToParse("ac");
});
it("cannot access variables defined by following labeled elements", function() {
var parser = peg.generate(
'start = &{ return a === "a"; } a:"a"',
options
);
expect(parser).toFailToParse("a");
});
it("cannot access variables defined by subexpressions", function() {
var testcases = [
{
grammar: 'start = (a:"a") &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = (a:"a")? &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = (a:"a")* &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = (a:"a")+ &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = $(a:"a") &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = &(a:"a") "a" &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = !(a:"a") "b" &{ return a === "a"; }',
input: "b"
},
{
grammar: 'start = b:(a:"a") &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = ("a" b:"b" "c") &{ return b === "b"; }',
input: "abc"
},
{
grammar: 'start = (a:"a" { return a; }) &{ return a === "a"; }',
input: "a"
},
{
grammar: 'start = ("a" / b:"b" / "c") &{ return b === "b"; }',
input: "b"
}
],
parser, i;
for (i = 0; i < testcases.length; i++) {
parser = peg.generate(testcases[i].grammar, options);
expect(parser).toFailToParse(testcases[i].input);
}
});
});
describe("in outer sequence", function() {
it("can access variables defined by preceding labeled elements", function() {
var parser = peg.generate(
'start = a:"a" ("b" &{ return a === "a"; })',
options
);
expect(parser).toParse("ab");
});
it("cannot access variable defined by labeled predicate element", function() {
var parser = peg.generate(
'start = "a" b:("b" &{ return b === undefined; }) "c"',
options
);
expect(parser).toFailToParse("abc");
});
it("cannot access variables defined by following labeled elements", function() {
var parser = peg.generate(
'start = ("a" &{ return b === "b"; }) b:"b"',
options
);
expect(parser).toFailToParse("ab");
});
});
});
describe("initializer variables & functions", function() {
it("can access variables defined in the initializer", function() {
var parser = peg.generate([
'{ var v = 42 }',
'start = &{ return v === 42; }'
].join("\n"), options);
expect(parser).toParse("");
});
it("can access functions defined in the initializer", function() {
var parser = peg.generate([
'{ function f() { return 42; } }',
'start = &{ return f() === 42; }'
].join("\n"), options);
expect(parser).toParse("");
});
});
describe("available variables & functions", function() {
it("|parser| contains the parser object", function() {
var parser = peg.generate([
'{ var result; }',
'start = &{ result = parser; return true; } { return result; }'
].join("\n"), options);
expect(parser).toParse("", parser);
});
it("|options| contains options", function() {
var parser = peg.generate([
'{ var result; }',
'start = &{ result = options; return true; } { return result; }'
].join("\n"), options);
expect(parser).toParse("", { a: 42 }, { a: 42 });
});
it("|location| returns current location info", function() {
var parser = peg.generate([
'{ var result; }',
'start = line (nl+ line)* { return result; }',
'line = thing (" "+ thing)*',
'thing = digit / mark',
'digit = [0-9]',
'mark = &{ result = location(); return true; } "x"',
'nl = "\\r"? "\\n"'
].join("\n"), options);
expect(parser).toParse("1\n2\n\n3\n\n\n4 5 x", {
start: { offset: 13, line: 7, column: 5 },
end: { offset: 13, line: 7, column: 5 }
});
/* Newline representations */
expect(parser).toParse("1\nx", { // Unix
start: { offset: 2, line: 2, column: 1 },
end: { offset: 2, line: 2, column: 1 }
});
expect(parser).toParse("1\r\nx", { // Windows
start: { offset: 3, line: 2, column: 1 },
end: { offset: 3, line: 2, column: 1 }
});
});
});
});
describe("negative semantic predicate", function() {
describe("when the code returns a falsey value", function() {
it("returns |undefined|", function() {
/*
* The |""| is needed so that the parser doesn't return just
* |undefined| which we can't compare against in |toParse| due to the
* way optional parameters work.
*/
var parser = peg.generate('start = !{ return false; } ""', options);
expect(parser).toParse("", [undefined, ""]);
});
});
describe("when the code returns a truthy value", function() {
it("reports match failure", function() {
var parser = peg.generate('start = !{ return true; }', options);
expect(parser).toFailToParse("");
});
});
describe("label variables", function() {
describe("in containing sequence", function() {
it("can access variables defined by preceding labeled elements", function() {
var parser = peg.generate(
'start = a:"a" !{ return a !== "a"; }',
options
);
expect(parser).toParse("a");
});
it("cannot access variable defined by labeled predicate element", function() {
var parser = peg.generate(
'start = "a" b:!{ return b !== undefined; } "c"',
options
);
expect(parser).toFailToParse("ac");
});
it("cannot access variables defined by following labeled elements", function() {
var parser = peg.generate(
'start = !{ return a !== "a"; } a:"a"',
options
);
expect(parser).toFailToParse("a");
});
it("cannot access variables defined by subexpressions", function() {
var testcases = [
{
grammar: 'start = (a:"a") !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = (a:"a")? !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = (a:"a")* !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = (a:"a")+ !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = $(a:"a") !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = &(a:"a") "a" !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = !(a:"a") "b" !{ return a !== "a"; }',
input: "b"
},
{
grammar: 'start = b:(a:"a") !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = ("a" b:"b" "c") !{ return b !== "b"; }',
input: "abc"
},
{
grammar: 'start = (a:"a" { return a; }) !{ return a !== "a"; }',
input: "a"
},
{
grammar: 'start = ("a" / b:"b" / "c") !{ return b !== "b"; }',
input: "b"
}
],
parser, i;
for (i = 0; i < testcases.length; i++) {
parser = peg.generate(testcases[i].grammar, options);
expect(parser).toFailToParse(testcases[i].input);
}
});
});
describe("in outer sequence", function() {
it("can access variables defined by preceding labeled elements", function() {
var parser = peg.generate(
'start = a:"a" ("b" !{ return a !== "a"; })',
options
);
expect(parser).toParse("ab");
});
it("cannot access variable defined by labeled predicate element", function() {
var parser = peg.generate(
'start = "a" b:("b" !{ return b !== undefined; }) "c"',
options
);
expect(parser).toFailToParse("abc");
});
it("cannot access variables defined by following labeled elements", function() {
var parser = peg.generate(
'start = ("a" !{ return b !== "b"; }) b:"b"',
options
);
expect(parser).toFailToParse("ab");
});
});
});
describe("initializer variables & functions", function() {
it("can access variables defined in the initializer", function() {
var parser = peg.generate([
'{ var v = 42 }',
'start = !{ return v !== 42; }'
].join("\n"), options);
expect(parser).toParse("");
});
it("can access functions defined in the initializer", function() {
var parser = peg.generate([
'{ function f() { return 42; } }',
'start = !{ return f() !== 42; }'
].join("\n"), options);
expect(parser).toParse("");
});
});
describe("available variables & functions", function() {
it("|parser| contains the parser object", function() {
var parser = peg.generate([
'{ var result; }',
'start = !{ result = parser; return false; } { return result; }'
].join("\n"), options);
expect(parser).toParse("", parser);
});
it("|options| contains options", function() {
var parser = peg.generate([
'{ var result; }',
'start = !{ result = options; return false; } { return result; }'
].join("\n"), options);
expect(parser).toParse("", { a: 42 }, { a: 42 });
});
it("|location| returns current location info", function() {
var parser = peg.generate([
'{ var result; }',
'start = line (nl+ line)* { return result; }',
'line = thing (" "+ thing)*',
'thing = digit / mark',
'digit = [0-9]',
'mark = !{ result = location(); return false; } "x"',
'nl = "\\r"? "\\n"'
].join("\n"), options);
expect(parser).toParse("1\n2\n\n3\n\n\n4 5 x", {
start: { offset: 13, line: 7, column: 5 },
end: { offset: 13, line: 7, column: 5 }
});
/* Newline representations */
expect(parser).toParse("1\nx", { // Unix
start: { offset: 2, line: 2, column: 1 },
end: { offset: 2, line: 2, column: 1 }
});
expect(parser).toParse("1\r\nx", { // Windows
start: { offset: 3, line: 2, column: 1 },
end: { offset: 3, line: 2, column: 1 }
});
});
});
});
describe("group", function() {
describe("when the expression matches", function() {
it("returns its match result", function() {
var parser = peg.generate('start = ("a")', options);
expect(parser).toParse("a", "a");
});
});
describe("when the expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = ("a")', options);
expect(parser).toFailToParse("b");
});
});
});
describe("optional", function() {
describe("when the expression matches", function() {
it("returns its match result", function() {
var parser = peg.generate('start = "a"?', options);
expect(parser).toParse("a", "a");
});
});
describe("when the expression doesn't match", function() {
it("returns |null|", function() {
var parser = peg.generate('start = "a"?', options);
expect(parser).toParse("", null);
});
});
});
describe("zero or more", function() {
describe("when the expression matches zero or more times", function() {
it("returns an array of its match results", function() {
var parser = peg.generate('start = "a"*', options);
expect(parser).toParse("", []);
expect(parser).toParse("a", ["a"]);
expect(parser).toParse("aaa", ["a", "a", "a"]);
});
});
});
describe("one or more", function() {
describe("when the expression matches one or more times", function() {
it("returns an array of its match results", function() {
var parser = peg.generate('start = "a"+', options);
expect(parser).toParse("a", ["a"]);
expect(parser).toParse("aaa", ["a", "a", "a"]);
});
});
describe("when the expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = "a"+', options);
expect(parser).toFailToParse("");
});
});
});
describe("text", function() {
describe("when the expression matches", function() {
it("returns the matched text", function() {
var parser = peg.generate('start = $("a" "b" "c")', options);
expect(parser).toParse("abc", "abc");
});
});
describe("when the expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = $("a")', options);
expect(parser).toFailToParse("b");
});
});
});
describe("positive simple predicate", function() {
describe("when the expression matches", function() {
it("returns |undefined|", function() {
var parser = peg.generate('start = &"a" "a"', options);
expect(parser).toParse("a", [undefined, "a"]);
});
it("resets parse position", function() {
var parser = peg.generate('start = &"a" "a"', options);
expect(parser).toParse("a");
});
});
describe("when the expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = &"a"', options);
expect(parser).toFailToParse("b");
});
it("discards any expectations recorded when matching the expression", function() {
var parser = peg.generate('start = "a" / &"b" / "c"', options);
expect(parser).toFailToParse("d", {
expected: [
{ type: "literal", text: "a", ignoreCase: false },
{ type: "literal", text: "c", ignoreCase: false }
]
});
});
});
});
describe("negative simple predicate", function() {
describe("when the expression matches", function() {
it("reports match failure", function() {
var parser = peg.generate('start = !"a"', options);
expect(parser).toFailToParse("a");
});
});
describe("when the expression doesn't match", function() {
it("returns |undefined|", function() {
var parser = peg.generate('start = !"a" "b"', options);
expect(parser).toParse("b", [undefined, "b"]);
});
it("resets parse position", function() {
var parser = peg.generate('start = !"a" "b"', options);
expect(parser).toParse("b");
});
it("discards any expectations recorded when matching the expression", function() {
var parser = peg.generate('start = "a" / !"b" / "c"', options);
expect(parser).toFailToParse("b", {
expected: [
{ type: "literal", text: "a", ignoreCase: false },
{ type: "literal", text: "c", ignoreCase: false }
]
});
});
});
});
describe("label", function() {
describe("when the expression matches", function() {
it("returns its match result", function() {
var parser = peg.generate('start = a:"a"', options);
expect(parser).toParse("a", "a");
});
});
describe("when the expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = a:"a"', options);
expect(parser).toFailToParse("b");
});
});
});
describe("sequence", function() {
describe("when all expressions match", function() {
it("returns an array of their match results", function() {
var parser = peg.generate('start = "a" "b" "c"', options);
expect(parser).toParse("abc", ["a", "b", "c"]);
});
});
describe("when any expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = "a" "b" "c"', options);
expect(parser).toFailToParse("dbc");
expect(parser).toFailToParse("adc");
expect(parser).toFailToParse("abd");
});
it("resets parse position", function() {
var parser = peg.generate('start = "a" "b" / "a"', options);
expect(parser).toParse("a", "a");
});
});
});
describe("action", function() {
describe("when the expression matches", function() {
it("returns the value returned by the code", function() {
var parser = peg.generate('start = "a" { return 42; }', options);
expect(parser).toParse("a", 42);
});
describe("label variables", function() {
describe("in the expression", function() {
it("can access variable defined by labeled expression", function() {
var parser = peg.generate('start = a:"a" { return a; }', options);
expect(parser).toParse("a", "a");
});
it("can access variables defined by labeled sequence elements", function() {
var parser = peg.generate(
'start = a:"a" b:"b" c:"c" { return [a, b, c]; }',
options
);
expect(parser).toParse("abc", ["a", "b", "c"]);
});
it("cannot access variables defined by subexpressions", function() {
var testcases = [
{
grammar: 'start = (a:"a") { return a; }',
input: "a"
},
{
grammar: 'start = (a:"a")? { return a; }',
input: "a"
},
{
grammar: 'start = (a:"a")* { return a; }',
input: "a"
},
{
grammar: 'start = (a:"a")+ { return a; }',
input: "a"
},
{
grammar: 'start = $(a:"a") { return a; }',
input: "a"
},
{
grammar: 'start = &(a:"a") "a" { return a; }',
input: "a"
},
{
grammar: 'start = !(a:"a") "b" { return a; }',
input: "b"
},
{
grammar: 'start = b:(a:"a") { return a; }',
input: "a"
},
{
grammar: 'start = ("a" b:"b" "c") { return b; }',
input: "abc"
},
{
grammar: 'start = (a:"a" { return a; }) { return a; }',
input: "a"
},
{
grammar: 'start = ("a" / b:"b" / "c") { return b; }',
input: "b"
}
],
parser, i;
for (i = 0; i < testcases.length; i++) {
parser = peg.generate(testcases[i].grammar, options);
expect(parser).toFailToParse(testcases[i].input);
}
});
});
describe("in outer sequence", function() {
it("can access variables defined by preceding labeled elements", function() {
var parser = peg.generate(
'start = a:"a" ("b" { return a; })',
options
);
expect(parser).toParse("ab", ["a", "a"]);
});
it("cannot access variable defined by labeled action element", function() {
var parser = peg.generate(
'start = "a" b:("b" { return b; }) c:"c"',
options
);
expect(parser).toFailToParse("abc");
});
it("cannot access variables defined by following labeled elements", function() {
var parser = peg.generate(
'start = ("a" { return b; }) b:"b"',
options
);
expect(parser).toFailToParse("ab");
});
});
});
describe("initializer variables & functions", function() {
it("can access variables defined in the initializer", function() {
var parser = peg.generate([
'{ var v = 42 }',
'start = "a" { return v; }'
].join("\n"), options);
expect(parser).toParse("a", 42);
});
it("can access functions defined in the initializer", function() {
var parser = peg.generate([
'{ function f() { return 42; } }',
'start = "a" { return f(); }'
].join("\n"), options);
expect(parser).toParse("a", 42);
});
});
describe("available variables & functions", function() {
it("|parser| contains the parser object", function() {
var parser = peg.generate(
'start = "a" { return parser; }',
options
);
expect(parser).toParse("a", parser);
});
it("|options| contains options", function() {
var parser = peg.generate(
'start = "a" { return options; }',
options
);
expect(parser).toParse("a", { a: 42 }, { a: 42 });
});
it("|text| returns text matched by the expression", function() {
var parser = peg.generate(
'start = "a" { return text(); }',
options
);
expect(parser).toParse("a", "a");
});
it("|location| returns location info of the expression", function() {
var parser = peg.generate([
'{ var result; }',
'start = line (nl+ line)* { return result; }',
'line = thing (" "+ thing)*',
'thing = digit / mark',
'digit = [0-9]',
'mark = "x" { result = location(); }',
'nl = "\\r"? "\\n"'
].join("\n"), options);
expect(parser).toParse("1\n2\n\n3\n\n\n4 5 x", {
start: { offset: 13, line: 7, column: 5 },
end: { offset: 14, line: 7, column: 6 }
});
/* Newline representations */
expect(parser).toParse("1\nx", { // Unix
start: { offset: 2, line: 2, column: 1 },
end: { offset: 3, line: 2, column: 2 }
});
expect(parser).toParse("1\r\nx", { // Windows
start: { offset: 3, line: 2, column: 1 },
end: { offset: 4, line: 2, column: 2 }
});
});
describe("|expected|", function() {
it("terminates parsing and throws an exception", function() {
var parser = peg.generate(
'start = "a" { expected("a"); }',
options
);
expect(parser).toFailToParse("a", {
message: 'Expected a but "a" found.',
expected: [{ type: "other", description: "a" }],
found: "a",
location: {
start: { offset: 0, line: 1, column: 1 },
end: { offset: 1, line: 1, column: 2 }
}
});
});
it("allows to set custom location info", function() {
var parser = peg.generate([
'start = "a" {',
' expected("a", {',
' start: { offset: 1, line: 1, column: 2 },',
' end: { offset: 2, line: 1, column: 3 }',
' });',
'}'
].join("\n"), options);
expect(parser).toFailToParse("a", {
message: 'Expected a but "a" found.',
expected: [{ type: "other", description: "a" }],
found: "a",
location: {
start: { offset: 1, line: 1, column: 2 },
end: { offset: 2, line: 1, column: 3 }
}
});
});
});
describe("|error|", function() {
it("terminates parsing and throws an exception", function() {
var parser = peg.generate(
'start = "a" { error("a"); }',
options
);
expect(parser).toFailToParse("a", {
message: "a",
found: "a",
expected: null,
location: {
start: { offset: 0, line: 1, column: 1 },
end: { offset: 1, line: 1, column: 2 }
}
});
});
it("allows to set custom location info", function() {
var parser = peg.generate([
'start = "a" {',
' error("a", {',
' start: { offset: 1, line: 1, column: 2 },',
' end: { offset: 2, line: 1, column: 3 }',
' });',
'}'
].join("\n"), options);
expect(parser).toFailToParse("a", {
message: "a",
expected: null,
found: "a",
location: {
start: { offset: 1, line: 1, column: 2 },
end: { offset: 2, line: 1, column: 3 }
}
});
});
});
});
});
describe("when the expression doesn't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = "a" { return 42; }', options);
expect(parser).toFailToParse("b");
});
it("doesn't execute the code", function() {
var parser = peg.generate(
'start = "a" { throw "Boom!"; } / "b"',
options
);
expect(parser).toParse("b");
});
});
});
describe("choice", function() {
describe("when any expression matches", function() {
it("returns its match result", function() {
var parser = peg.generate('start = "a" / "b" / "c"', options);
expect(parser).toParse("a", "a");
expect(parser).toParse("b", "b");
expect(parser).toParse("c", "c");
});
});
describe("when all expressions don't match", function() {
it("reports match failure", function() {
var parser = peg.generate('start = "a" / "b" / "c"', options);
expect(parser).toFailToParse("d");
});
});
});
describe("error reporting", function() {
describe("behavior", function() {
it("reports only the rightmost error", function() {
var parser = peg.generate('start = "a" "b" / "a" "c" "d"', options);
expect(parser).toFailToParse("ace", {
expected: [{ type: "literal", text: "d", ignoreCase: false }]
});
});
});
describe("expectations reporting", function() {
it("reports expectations correctly with no alternative", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("ab", {
expected: [{ type: "end" }]
});
});
it("reports expectations correctly with one alternative", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("b", {
expected: [{ type: "literal", text: "a", ignoreCase: false }]
});
});
it("reports expectations correctly with multiple alternatives", function() {
var parser = peg.generate('start = "a" / "b" / "c"', options);
expect(parser).toFailToParse("d", {
expected: [
{ type: "literal", text: "a", ignoreCase: false },
{ type: "literal", text: "b", ignoreCase: false },
{ type: "literal", text: "c", ignoreCase: false }
]
});
});
});
describe("found string reporting", function() {
it("reports found string correctly at the end of input", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("", { found: null });
});
it("reports found string correctly in the middle of input", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("b", { found: "b" });
});
});
describe("message building", function() {
it("builds message correctly with no alternative", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("ab", {
message: 'Expected end of input but "b" found.'
});
});
it("builds message correctly with one alternative", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("b", {
message: 'Expected "a" but "b" found.'
});
});
it("builds message correctly with multiple alternatives", function() {
var parser = peg.generate('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.generate('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.generate('start = "a"', options);
expect(parser).toFailToParse("b", {
message: 'Expected "a" but "b" found.'
});
});
it("removes duplicates from expectations", function() {
var parser = peg.generate('start = "a" / "a"', options);
expect(parser).toFailToParse("b", {
message: 'Expected "a" but "b" found.'
});
});
it("sorts expectations", function() {
var parser = peg.generate('start = "c" / "b" / "a"', options);
expect(parser).toFailToParse("d", {
message: 'Expected "a", "b" or "c" but "d" found.'
});
});
});
describe("position reporting", function() {
it("reports position correctly at the end of input", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("", {
location: {
start: { offset: 0, line: 1, column: 1 },
end: { offset: 0, line: 1, column: 1 }
}
});
});
it("reports position correctly in the middle of input", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("b", {
location: {
start: { offset: 0, line: 1, column: 1 },
end: { offset: 1, line: 1, column: 2 }
}
});
});
it("reports position correctly with trailing input", function() {
var parser = peg.generate('start = "a"', options);
expect(parser).toFailToParse("aa", {
location: {
start: { offset: 1, line: 1, column: 2 },
end: { offset: 2, line: 1, column: 3 }
}
});
});
it("reports position correctly in complex cases", function() {
var parser = peg.generate([
'start = line (nl+ line)*',
'line = digit (" "+ digit)*',
'digit = [0-9]',
'nl = "\\r"? "\\n"'
].join("\n"), options);
expect(parser).toFailToParse("1\n2\n\n3\n\n\n4 5 x", {
location: {
start: { offset: 13, line: 7, column: 5 },
end: { offset: 14, line: 7, column: 6 }
}
});
/* Newline representations */
expect(parser).toFailToParse("1\nx", { // Old Mac
location: {
start: { offset: 2, line: 2, column: 1 },
end: { offset: 3, line: 2, column: 2 }
}
});
expect(parser).toFailToParse("1\r\nx", { // Windows
location: {
start: { offset: 3, line: 2, column: 1 },
end: { offset: 4, line: 2, column: 2 }
}
});
});
});
});
/*
* 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.generate([
'Expr = Sum',
'Sum = first:Product rest:(("+" / "-") Product)* {',
' var result = first, i;',
' for (i = 0; i < rest.length; i++) {',
' if (rest[i][0] == "+") { result += rest[i][1]; }',
' if (rest[i][0] == "-") { result -= rest[i][1]; }',
' }',
' return result;',
' }',
'Product = first:Value rest:(("*" / "/") Value)* {',
' var result = first, i;',
' for (i = 0; i < rest.length; i++) {',
' if (rest[i][0] == "*") { result *= rest[i][1]; }',
' if (rest[i][0] == "/") { result /= rest[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.generate([
'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].join(""); }',
'B = b:"b" B:B? c:"c" { return [b, B, c].join(""); }'
].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.generate([
'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*)"
);
});
});
});
});