/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* * * Date: 15 July 2002 * SUMMARY: Testing identifiers with double-byte names * See http://bugzilla.mozilla.org/show_bug.cgi?id=58274 * * Here is a sample of the problem: * * js> function f\u02B1 () {} * * js> f\u02B1.toSource(); * function f¦() {} * * js> f\u02B1.toSource().toSource(); * (new String("function f\xB1() {}")) * * * See how the high-byte information (the 02) has been lost? * The same thing was happening with the toString() method: * * js> f\u02B1.toString(); * * function f¦() { * } * * js> f\u02B1.toString().toSource(); * (new String("\nfunction f\xB1() {\n}\n")) *
*/ //----------------------------------------------------------------------------- var UBound = 0; var BUGNUMBER = 58274; var summary = 'Testing identifiers with double-byte names'; var status = ''; var statusitems = []; var actual = ''; var actualvalues = []; var expect= ''; var expectedvalues = [];
/* * Define a function that uses double-byte identifiers in * "every possible way" * * Then recover each double-byte identifier via f.toString(). * To make this easier, put a 'Z' token before every one. * * Our eval string will be: * * sEval = "function Z\u02b1(Z\u02b2, b) { * try { Z\u02b3 : var Z\u02b4 = Z\u02b1; } * catch (Z\u02b5) { for (var Z\u02b6 in Z\u02b5) * {for (1; 1<0; Z\u02b7++) {new Array()[Z\u02b6] = 1;} };} }"; * * It will be helpful to build this string in stages:
*/ var s0 = 'function Z'; var s1 = '\u02b1(Z'; var s2 = '\u02b2, b) {try { Z'; var s3 = '\u02b3 : var Z'; var s4 = '\u02b4 = Z'; var s5 = '\u02b1; } catch (Z' var s6 = '\u02b5) { for (var Z'; var s7 = '\u02b6 in Z'; var s8 = '\u02b5){for (1; 1<0; Z'; var s9 = '\u02b7++) {new Array()[Z'; var s10 = '\u02b6] = 1;} };} }';
/* * Concatenate these and eval() to create the function Z\u02b1
*/ var sEval = s0 + s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10;
eval(sEval);
/* * Recover all the double-byte identifiers via Z\u02b1.toString(). * We'll recover the 1st one as arrID[1], the 2nd one as arrID[2], * and so on ...
*/ var arrID = getIdentifiers(Z\u02b1);
/* * Now check that we got back what we put in -
*/
status = inSection(1);
actual = arrID[1];
expect = s1.charAt(0);
addThis();
status = inSection(2);
actual = arrID[2];
expect = s2.charAt(0);
addThis();
status = inSection(3);
actual = arrID[3];
expect = s3.charAt(0);
addThis();
status = inSection(4);
actual = arrID[4];
expect = s4.charAt(0);
addThis();
status = inSection(5);
actual = arrID[5];
expect = s5.charAt(0);
addThis();
status = inSection(6);
actual = arrID[6];
expect = s6.charAt(0);
addThis();
status = inSection(7);
actual = arrID[7];
expect = s7.charAt(0);
addThis();
status = inSection(8);
actual = arrID[8];
expect = s8.charAt(0);
addThis();
status = inSection(9);
actual = arrID[9];
expect = s9.charAt(0);
addThis();
status = inSection(10);
actual = arrID[10];
expect = s10.charAt(0);
addThis();
/* * Goal: recover the double-byte identifiers from f.toString() * by getting the very next character after each 'Z' token. * * The return value will be an array |arr| indexed such that * |arr[1]| is the 1st identifier, |arr[2]| the 2nd, and so on. * * Note, however, f.toString() is implementation-independent. * For example, it may begin with '\nfunction' instead of 'function'. * * Rhino uses a Unicode representation for f.toString(); whereas * SpiderMonkey uses an ASCII representation, putting escape sequences * for non-ASCII characters. For example, if a function is called f\u02B1, * then in Rhino the toString() method will present a 2-character Unicode * string for its name, whereas SpiderMonkey will present a 7-character * ASCII string for its name: the string literal 'f\u02B1'. * * So we force the lexer to condense the string before we use it. * This will give uniform results in Rhino and SpiderMonkey.
*/ function getIdentifiers(f)
{ var str = condenseStr(f.toString()); var arr = str.split('Z');
/* * The identifiers are the 1st char of each split substring * EXCEPT the first one, which is just ('\n' +) 'function '. * * Thus note the 1st identifier will be stored in |arr[1]|, * the 2nd one in |arr[2]|, etc., making the indexing easy -
*/ for (i in arr)
arr[i] = arr[i].charAt(0); return arr;
}
/* * This function is the opposite of a functions like escape(), which take * Unicode characters and return escape sequences for them. Here, we force * the lexer to turn escape sequences back into single characters. * * Note we can't simply do |eval(str)|, since in practice |str| will be an * identifier somewhere in the program (e.g. a function name); thus |eval(str)| * would return the object that the identifier represents: not what we want. * * So we surround |str| lexicographically with quotes to force the lexer to * evaluate it as a string. Have to strip out any linefeeds first, however -
*/ function condenseStr(str)
{ /* * You won't be able to do the next step if |str| has * any carriage returns or linefeeds in it. For example: * * js> eval("'" + '\nHello' + "'"); * 1: SyntaxError: unterminated string literal: * 1: ' * 1: ^ * * So replace them with the empty string -
*/
str = str.replace(/[\r\n]/g, '') return eval("'" + str + "'")
}
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.