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// A little pattern-matching library.
//
// Ported from js/src/tests/js1_8_5/reflect-parse/Match.js for use with devtools
// server xpcshell tests.
export const Match = (function () {
function Pattern(template) {
// act like a constructor even as a function
if (!(this instanceof Pattern)) {
return new Pattern(template);
}
this.template = template;
}
Pattern.prototype = {
match(act) {
return match(act, this.template);
},
matches(act) {
try {
return this.match(act);
} catch (e) {
if (e instanceof MatchError) {
return false;
}
}
return false;
},
assert(act, message) {
try {
return this.match(act);
} catch (e) {
if (e instanceof MatchError) {
throw new Error((message || "failed match") + ": " + e.message);
}
}
return false;
},
toString: () => "[object Pattern]",
};
Pattern.ANY = new Pattern();
Pattern.ANY.template = Pattern.ANY;
Pattern.NUMBER = new Pattern();
Pattern.NUMBER.match = function (act) {
if (typeof act !== "number") {
throw new MatchError("Expected number, got: " + quote(act));
}
};
Pattern.NATURAL = new Pattern();
Pattern.NATURAL.match = function (act) {
if (typeof act !== "number" || act !== Math.floor(act) || act < 0) {
throw new MatchError("Expected natural number, got: " + quote(act));
}
};
const quote = uneval;
function MatchError(msg) {
this.message = msg;
}
MatchError.prototype = {
toString() {
return "match error: " + this.message;
},
};
function isAtom(x) {
return (
typeof x === "number" ||
typeof x === "string" ||
typeof x === "boolean" ||
x === null ||
(typeof x === "object" && x instanceof RegExp)
);
}
function isObject(x) {
return x !== null && typeof x === "object";
}
function isFunction(x) {
return typeof x === "function";
}
function isArrayLike(x) {
return isObject(x) && "length" in x;
}
function matchAtom(act, exp) {
if (typeof exp === "number" && isNaN(exp)) {
if (typeof act !== "number" || !isNaN(act)) {
throw new MatchError("expected NaN, got: " + quote(act));
}
return true;
}
if (exp === null) {
if (act !== null) {
throw new MatchError("expected null, got: " + quote(act));
}
return true;
}
if (exp instanceof RegExp) {
if (!(act instanceof RegExp) || exp.source !== act.source) {
throw new MatchError("expected " + quote(exp) + ", got: " + quote(act));
}
return true;
}
switch (typeof exp) {
case "string":
if (act !== exp) {
throw new MatchError(
"expected " + quote(exp) + ", got " + quote(act)
);
}
return true;
case "boolean":
case "number":
if (exp !== act) {
throw new MatchError("expected " + exp + ", got " + quote(act));
}
return true;
}
throw new Error("bad pattern: " + exp.toSource());
}
function matchObject(act, exp) {
if (!isObject(act)) {
throw new MatchError("expected object, got " + quote(act));
}
for (const key in exp) {
if (!(key in act)) {
throw new MatchError(
"expected property " + quote(key) + " not found in " + quote(act)
);
}
match(act[key], exp[key]);
}
return true;
}
function matchFunction(act, exp) {
if (!isFunction(act)) {
throw new MatchError("expected function, got " + quote(act));
}
if (act !== exp) {
throw new MatchError(
"expected function: " + exp + "\nbut got different function: " + act
);
}
}
function matchArray(act, exp) {
if (!isObject(act) || !("length" in act)) {
throw new MatchError("expected array-like object, got " + quote(act));
}
const length = exp.length;
if (act.length !== exp.length) {
throw new MatchError(
"expected array-like object of length " + length + ", got " + quote(act)
);
}
for (let i = 0; i < length; i++) {
if (i in exp) {
if (!(i in act)) {
throw new MatchError(
"expected array property " + i + " not found in " + quote(act)
);
}
match(act[i], exp[i]);
}
}
return true;
}
function match(act, exp) {
if (exp === Pattern.ANY) {
return true;
}
if (exp instanceof Pattern) {
return exp.match(act);
}
if (isAtom(exp)) {
return matchAtom(act, exp);
}
if (isArrayLike(exp)) {
return matchArray(act, exp);
}
if (isFunction(exp)) {
return matchFunction(act, exp);
}
return matchObject(act, exp);
}
return { Pattern, MatchError };
})();
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