2f2152204a
Before this commit, the |expected| and |error| functions didn't halt the
parsing immediately, but triggered a regular match failure. After they
were called, the parser could backtrack, try another branches, and only
if no other branch succeeded, it triggered an exception with information
possibly based on parameters passed to the |expected| or |error|
function (this depended on positions where failures in other branches
have occurred).
While nice in theory, this solution didn't work well in practice. There
were at least two problems:
1. Action expression could have easily triggered a match failure later
in the input than the action itself. This resulted in the
action-triggered failure to be shadowed by the expression-triggered
one.
Consider the following example:
integer = digits:[0-9]+ {
var result = parseInt(digits.join(""), 10);
if (result % 2 === 0) {
error("The number must be an odd integer.");
return;
}
return result;
}
Given input "2", the |[0-9]+| expression would record a match
failure at position 1 (an unsuccessful attempt to parse yet another
digit after "2"). However, a failure triggered by the |error| call
would occur at position 0.
This problem could have been solved by silencing match failures in
action expressions, but that would lead to severe performance
problems (yes, I tried and measured). Other possible solutions are
hacks which I didn't want to introduce into PEG.js.
2. Triggering a match failure in action code could have lead to
unexpected backtracking.
Consider the following example:
class = "[" (charRange / char)* "]"
charRange = begin:char "-" end:char {
if (begin.data.charCodeAt(0) > end.data.charCodeAt(0)) {
error("Invalid character range: " + begin + "-" + end + ".");
}
// ...
}
char = [a-zA-Z0-9_\-]
Given input "[b-a]", the |charRange| rule would fail, but the
parser would try the |char| rule and succeed repeatedly, resulting
in "b-a" being parsed as a sequence of three |char|'s, which it is
not.
This problem could have been solved by using negative predicates,
but that would complicate the grammar and still wouldn't get rid of
unintuitive behavior.
Given these problems I decided to change the semantics of the |expected|
and |error| functions. They don't interact with regular match failure
mechanism anymore, but they cause and immediate parse failure by
throwing an exception. I think this is more intuitive behavior with less
harmful side effects.
The disadvantage of the new approach is that one can't backtrack from an
action-triggered error. I don't see this as a big deal as I think this
will be rarely needed and one can always use a semantic predicate as a
workaround.
Speed impact
------------
Before: 993.84 kB/s
After: 998.05 kB/s
Difference: 0.42%
Size impact
-----------
Before: 1019968 b
After: 975434 b
Difference: -4.37%
(Measured by /tools/impact with Node.js v0.6.18 on x86_64 GNU/Linux.)
1189 lines
39 KiB
JavaScript
1189 lines
39 KiB
JavaScript
describe("generated parser", function() {
|
|
function vary(names, block) {
|
|
var values = {
|
|
cache: [false, true],
|
|
optimize: ["speed", "size"]
|
|
};
|
|
|
|
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", "optimize"], block);
|
|
}
|
|
|
|
beforeEach(function() {
|
|
this.addMatchers({
|
|
toParse: function(input) {
|
|
var options = arguments.length > 2 ? arguments[1] : {},
|
|
expected = arguments[arguments.length - 1],
|
|
result;
|
|
|
|
try {
|
|
result = this.actual.parse(input, options);
|
|
|
|
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);
|
|
} catch (e) {
|
|
this.message = function() {
|
|
return "Expected " + jasmine.pp(input) + " "
|
|
+ "with options " + jasmine.pp(options) + " "
|
|
+ "to parse as " + jasmine.pp(expected) + ", "
|
|
+ "but it failed to parse with message "
|
|
+ jasmine.pp(e.message) + ".";
|
|
};
|
|
|
|
return false;
|
|
}
|
|
},
|
|
|
|
toFailToParse: function(input) {
|
|
var options = arguments.length > 2 ? arguments[1] : {},
|
|
details = arguments.length > 1
|
|
? arguments[arguments.length - 1]
|
|
: undefined;
|
|
|
|
/*
|
|
* 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) + " "
|
|
+ "with options " + jasmine.pp(options) + " "
|
|
+ "to fail to parse"
|
|
+ (details ? " with details " + jasmine.pp(details) : "") + ", "
|
|
+ "but " + jasmine.pp(key) + " "
|
|
+ "is " + jasmine.pp(value) + ".";
|
|
};
|
|
}
|
|
|
|
var result;
|
|
|
|
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) {
|
|
/*
|
|
* Should be at the top level but then JSHint complains about bad for
|
|
* in variable.
|
|
*/
|
|
var key;
|
|
|
|
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 (!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"; }',
|
|
'c = "x" { return "c"; }'
|
|
].join("\n"), { allowedStartRules: ["b", "c"] });
|
|
|
|
describe("start rule", function() {
|
|
describe("without the |startRule| option", function() {
|
|
it("uses the first allowed rule", function() {
|
|
expect(parser).toParse("x", "b");
|
|
});
|
|
});
|
|
|
|
describe("when the |startRule| option specifies allowed rule", function() {
|
|
it("uses the specified rule", function() {
|
|
expect(parser).toParse("x", { startRule: "b" }, "b");
|
|
expect(parser).toParse("x", { startRule: "c" }, "c");
|
|
});
|
|
});
|
|
|
|
describe("when the |startRule| option specifies disallowed rule", function() {
|
|
it("throws exception", function() {
|
|
expect(parser).toFailToParse("x", { startRule: "a" }, {
|
|
message: "Can't start parsing from rule \"a\"."
|
|
});
|
|
});
|
|
});
|
|
});
|
|
});
|
|
|
|
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);
|
|
});
|
|
|
|
it("can use the |text| function", function() {
|
|
var parser = PEG.buildParser([
|
|
'{ var result = text(); }',
|
|
'start = "a" { return result; }'
|
|
].join("\n"), options);
|
|
|
|
expect(parser).toParse("a", "");
|
|
});
|
|
|
|
it("can use the |offset| function to get the current parse position", function() {
|
|
var parser = PEG.buildParser([
|
|
'{ var result = offset(); }',
|
|
'start = "a" { return result; }'
|
|
].join("\n"), options);
|
|
|
|
expect(parser).toParse("a", 0);
|
|
});
|
|
|
|
it("can use the |line| and |column| functions to get the current line and column", function() {
|
|
var parser = PEG.buildParser([
|
|
'{ var result = [line(), column()]; }',
|
|
'start = "a" { return result; }'
|
|
].join("\n"), options);
|
|
|
|
expect(parser).toParse("a", [1, 1]);
|
|
});
|
|
|
|
it("can use options passed to the parser", function() {
|
|
var parser = PEG.buildParser([
|
|
'{ var result = options; }',
|
|
'start = "a" { return result; }'
|
|
].join("\n"), options);
|
|
|
|
expect(parser).toParse("a", { a: 42 }, { 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);
|
|
});
|
|
}
|
|
});
|
|
|
|
describe("named matching", function() {
|
|
var parser = PEG.buildParser('start "start" = "a"');
|
|
|
|
it("delegates to the expression", function() {
|
|
expect(parser).toParse("a", "a");
|
|
expect(parser).toFailToParse("b");
|
|
});
|
|
|
|
it("overwrites expected string on failure", function() {
|
|
expect(parser).toFailToParse("b", {
|
|
expected: [{ type: "other", description: "start" }]
|
|
});
|
|
});
|
|
});
|
|
|
|
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("action code", function() {
|
|
it("tranforms the expression result by returnung a value", function() {
|
|
var parser = PEG.buildParser('start = "a" { return 42; }', options);
|
|
|
|
expect(parser).toParse("a", 42);
|
|
});
|
|
|
|
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 |text| function to get the text matched by the expression", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" "b" "c" { return text(); }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("abc", "abc");
|
|
});
|
|
|
|
it("can use the |offset| function to get the current parse position", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" ("b" { return offset(); })',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("ab", ["a", 1]);
|
|
});
|
|
|
|
it("can use the |line| and |column| functions 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 the |expected| function to trigger an error", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" { expected("a"); }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toFailToParse("a", {
|
|
message: 'Expected a but "a" found.',
|
|
expected: [{ type: "other", description: "a" }],
|
|
found: "a",
|
|
offset: 0,
|
|
line: 1,
|
|
column: 1
|
|
});
|
|
});
|
|
|
|
it("can use the |error| function to trigger an error", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" { error("a"); }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toFailToParse("a", {
|
|
message: "a",
|
|
expected: null,
|
|
found: "a",
|
|
offset: 0,
|
|
line: 1,
|
|
column: 1
|
|
});
|
|
});
|
|
|
|
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("can use options passed to the parser", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" { return options; }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("a", { a: 42 }, { a: 42 });
|
|
});
|
|
});
|
|
|
|
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("text matching", function() {
|
|
it("matches correctly", function() {
|
|
var parser = PEG.buildParser('start = $("a" "b" "c")', options);
|
|
|
|
expect(parser).toParse("abc", "abc");
|
|
});
|
|
});
|
|
|
|
describe("simple and matching", function() {
|
|
it("matches correctly", function() {
|
|
var parser = PEG.buildParser('start = &"a" "a"', options);
|
|
|
|
expect(parser).toParse("a", [undefined, "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", [undefined, "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", [undefined, "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("", undefined);
|
|
});
|
|
|
|
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", undefined]);
|
|
});
|
|
|
|
it("can use the |text| function", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" &{ return text() === ""; }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("a", ["a", undefined]);
|
|
});
|
|
|
|
it("can use the |offset| function to get the current parse position", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" &{ return offset() === 1; }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("a", ["a", undefined]);
|
|
});
|
|
|
|
it("can use the |line| and |column| functions 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", undefined]);
|
|
});
|
|
|
|
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", undefined]);
|
|
});
|
|
|
|
it("can use options passed to the parser", function() {
|
|
var parser = PEG.buildParser([
|
|
'{ var result; }',
|
|
'start = "a" &{ result = options; return true; } { return result; }'
|
|
].join("\n"), options);
|
|
|
|
expect(parser).toParse("a", { a: 42 }, { a: 42 });
|
|
});
|
|
});
|
|
|
|
describe("semantic not code", function() {
|
|
it("causes successful match by returning |false|", function() {
|
|
var parser = PEG.buildParser('start = !{ return false; }', options);
|
|
|
|
expect(parser).toParse("", undefined);
|
|
});
|
|
|
|
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", undefined]);
|
|
});
|
|
|
|
it("can use the |text| function", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" !{ return text() !== ""; }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("a", ["a", undefined]);
|
|
});
|
|
|
|
it("can use the |offset| function to get the current parse position", function() {
|
|
var parser = PEG.buildParser(
|
|
'start = "a" !{ return offset() !== 1; }',
|
|
options
|
|
);
|
|
|
|
expect(parser).toParse("a", ["a", undefined]);
|
|
});
|
|
|
|
it("can use the |line| and |column| functions 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", undefined]);
|
|
});
|
|
|
|
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", undefined]);
|
|
});
|
|
|
|
it("can use options passed to the parser", function() {
|
|
var parser = PEG.buildParser([
|
|
'{ var result; }',
|
|
'start = "a" !{ result = options; return false; } { return result; }'
|
|
].join("\n"), options);
|
|
|
|
expect(parser).toParse("a", { a: 42 }, { a: 42 });
|
|
});
|
|
});
|
|
|
|
describe("optional matching", function() {
|
|
it("matches correctly", function() {
|
|
var parser = PEG.buildParser('start = "a"?', options);
|
|
|
|
expect(parser).toParse("", null);
|
|
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("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 expectation correctly on failure", function() {
|
|
var parser = PEG.buildParser('start = "a"', options);
|
|
|
|
expect(parser).toFailToParse("b", {
|
|
expected: [{ type: "literal", value: "a", description: '"a"' }]
|
|
});
|
|
});
|
|
});
|
|
|
|
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 expectation correctly on failure", function() {
|
|
var parser = PEG.buildParser('start = [a]', options);
|
|
|
|
expect(parser).toFailToParse("b", {
|
|
expected: [{ type: "class", value: "[a]", description: "[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 expectation correctly on failure", function() {
|
|
var parser = PEG.buildParser('start = .', options);
|
|
|
|
expect(parser).toFailToParse("", {
|
|
expected: [{ type: "any", description: "any character" }]
|
|
});
|
|
});
|
|
});
|
|
|
|
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: [{ type: "literal", value: "d", description: '"d"' }]
|
|
});
|
|
});
|
|
});
|
|
|
|
describe("expectations reporting", function() {
|
|
it("reports expectations correctly with no alternative", function() {
|
|
var parser = PEG.buildParser('start = ', options);
|
|
|
|
expect(parser).toFailToParse("a", { expected: [] });
|
|
});
|
|
|
|
it("reports expectations correctly with one alternative", function() {
|
|
var parser = PEG.buildParser('start = "a"', options);
|
|
|
|
expect(parser).toFailToParse("b", {
|
|
expected: [{ type: "literal", value: "a", description: '"a"' }]
|
|
});
|
|
});
|
|
|
|
it("reports expectations correctly with multiple alternatives", function() {
|
|
var parser = PEG.buildParser('start = "a" / "b" / "c"', options);
|
|
|
|
expect(parser).toFailToParse("d", {
|
|
expected: [
|
|
{ type: "literal", value: "a", description: '"a"' },
|
|
{ type: "literal", value: "b", description: '"b"' },
|
|
{ type: "literal", value: "c", description: '"c"' }
|
|
]
|
|
});
|
|
});
|
|
|
|
it("removes duplicates from expectations", function() {
|
|
/*
|
|
* There was a bug in the code that manifested only with three
|
|
* duplicates. This is why the following test uses three choices
|
|
* instead of seemingly sufficient two.
|
|
*
|
|
* See https://github.com/dmajda/pegjs/pull/146.
|
|
*/
|
|
var parser = PEG.buildParser('start = "a" / "a" / "a"', options);
|
|
|
|
expect(parser).toFailToParse("b", {
|
|
expected: [{ type: "literal", value: "a", description: '"a"' }]
|
|
});
|
|
});
|
|
|
|
it("sorts expectations", function() {
|
|
var parser = PEG.buildParser('start = "c" / "b" / "a"', options);
|
|
|
|
expect(parser).toFailToParse("d", {
|
|
expected: [
|
|
{ type: "literal", value: "a", description: '"a"' },
|
|
{ type: "literal", value: "b", description: '"b"' },
|
|
{ type: "literal", value: "c", description: '"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
|
|
});
|
|
});
|
|
});
|
|
});
|
|
|
|
describe("allowed start rules", function() {
|
|
var grammar = [
|
|
'a = "x"',
|
|
'b = "x"',
|
|
'c = "x"'
|
|
].join("\n");
|
|
|
|
describe("without the |allowedStartRules| option", function() {
|
|
var parser = PEG.buildParser(grammar);
|
|
|
|
it("allows the first rule", function() {
|
|
expect(parser).toParse("x", { startRule: "a" }, "x");
|
|
});
|
|
|
|
it("does not allow any other rules", function() {
|
|
expect(parser).toFailToParse("x", { startRule: "b" }, { });
|
|
expect(parser).toFailToParse("x", { startRule: "c" }, { });
|
|
});
|
|
});
|
|
|
|
describe("with the |allowedStartRules| option", function() {
|
|
var parser = PEG.buildParser(grammar, { allowedStartRules: ["b", "c"] });
|
|
|
|
it("allows the specified rules", function() {
|
|
expect(parser).toParse("x", { startRule: "b" }, "x");
|
|
expect(parser).toParse("x", { startRule: "c" }, "x");
|
|
});
|
|
|
|
it("does not allow any other rules", function() {
|
|
expect(parser).toFailToParse("x", { startRule: "a" }, { });
|
|
});
|
|
});
|
|
});
|
|
|
|
describe("output", function() {
|
|
var grammar = 'start = "a"';
|
|
|
|
describe("without the |output| option", function() {
|
|
it("returns a parser object", function() {
|
|
var parser = PEG.buildParser(grammar);
|
|
|
|
expect(typeof parser).toBe("object");
|
|
expect(parser).toParse("a", "a");
|
|
});
|
|
});
|
|
|
|
describe("when the |output| option is set to \"parser\"", function() {
|
|
it("returns a parser object", function() {
|
|
var parser = PEG.buildParser(grammar, { output: "parser" });
|
|
|
|
expect(typeof parser).toBe("object");
|
|
expect(parser).toParse("a", "a");
|
|
});
|
|
});
|
|
|
|
describe("when the |output| option is set to \"source\"", function() {
|
|
it("returns a parser source code", function() {
|
|
var source = PEG.buildParser(grammar, { output: "source" });
|
|
|
|
expect(typeof source).toBe("string");
|
|
expect(eval(source)).toParse("a", "a");
|
|
});
|
|
});
|
|
});
|
|
|
|
/*
|
|
* 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].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.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*)"
|
|
);
|
|
});
|
|
});
|
|
});
|
|
});
|