Makes mocha.js YUI-compressible

[ArnaudBrousseau]

Before this diff, trying to compress mocha.js with YUI compressor would result in the following output

=> java -jar yuicompressor-2.4.8.jar mocha.js
[ERROR] in mocha.js
  1733:19:missing name after . operator
[ERROR] in mocha.js
  1734:16:identifier is a reserved word
[ERROR] in mocha.js
  1735:9:missing ; before statement
[ERROR] in mocha.js
  1736:17:identifier is a reserved word
[ERROR] in mocha.js
  1738:2:missing ) after argument list
[ERROR] in mocha.js
  1787:15:missing ( before function parameters.
[ERROR] in mocha.js
  1787:15:missing } after function body
[ERROR] in mocha.js
  1788:22:missing ; before statement
[ERROR] in mocha.js
  1789:22:invalid return
[ERROR] in mocha.js
  1790:22:invalid return
[ERROR] in mocha.js
  1791:22:invalid return
[ERROR] in mocha.js
  1792:9:invalid return
[ERROR] in mocha.js
  1793:1:syntax error
[ERROR] in mocha.js
  1803:14:identifier is a reserved word
[ERROR] in mocha.js
  1809:1:syntax error
[ERROR] in mocha.js
  1815:30:missing ; before statement
[ERROR] in mocha.js
  1816:21:missing ; before statement
[ERROR] in mocha.js
  1817:27:invalid return
[ERROR] in mocha.js
  1818:9:invalid return
[ERROR] in mocha.js
  1819:1:syntax error
[ERROR] in mocha.js
  1821:2:syntax error
[ERROR] in mocha.js
  5600:1:syntax error
[ERROR] in mocha.js
  1:0:Compilation produced 22 syntax errors.
org.mozilla.javascript.EvaluatorException: Compilation produced 22 syntax errors.
    at com.yahoo.platform.yui.compressor.YUICompressor$1.runtimeError(YUICompressor.java:172)
    at org.mozilla.javascript.Parser.parse(Parser.java:396)
    at org.mozilla.javascript.Parser.parse(Parser.java:340)
    at com.yahoo.platform.yui.compressor.JavaScriptCompressor.parse(JavaScriptCompressor.java:315)
    at com.yahoo.platform.yui.compressor.JavaScriptCompressor.<init>(JavaScriptCompressor.java:536)
    at com.yahoo.platform.yui.compressor.YUICompressor.main(YUICompressor.java:147)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.yahoo.platform.yui.compressor.Bootstrap.main(Bootstrap.java:21)

After this change, mocha.js compresses as you would expect, without errors.

The reason why YUI failed to compress mocha.js: it uses of long and short as identifiers. They are reserved word in ECMAScript since ECMAScript v2:

Cheers,
Arnaud.

[travisjeffery]

your yui's out of date: http://www.ecma-international.org/ecma-262/5.1/#sec-7.6.1.2, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Reserved_Words

[ArnaudBrousseau]

While long isn't reserved in ECMAScript 5.1 anymore (my bad for not catching that, I should've said so in my original message), backward-compatibility with older JS engines impose that we shouldn't name vars or functions with any of the reserved keywords ever put in a spec.
Set of reserved words in JS = union of all the reserved words for all specs. See http://mathiasbynens.be/notes/reserved-keywords

I believe this MDN article is out of date. I'll update.

[ArnaudBrousseau]

@travisjeffery Updated MDN with all FutureReservedWords across ECMA specs. Looking at YUI it seems they're actually missing a few of them ;)

[travisjeffery]

ok made the change. didn't merge your commit tho since you made the change in the generated file and i didn't like the function names.

[ArnaudBrousseau]

@travisjeffery Thanks a lot! New function names lg2m. And sorry for modifying the wrong file. TIL :)

[campaul]

This wasn't fully fixed. Having options.long still causes YUI to fail.

[boneskull]

@campaul should be fixed now in master