Using the '&'-operator after a subselector doesn't work as expected

[marklagendijk]

Using the ‘&’ operator after a selector doesn’t work properly. In the output the ‘&’ parts get places before the subselector instead of after it:

#main {
    #content {
        .class {
            position: absolute;
            #container & {
                position: relative;
            }
        }
    }
}

Should output:

#main #content .class { 
    position: absolute; 
}
#container #main #content .class { 
    position:relative; 
}

But this is what it does output:

#main #content .class { 
    position: absolute; 
}
#main #content .class #container { 
    position: relative; 
}

Note: this usage of the ‘&’-operator isn’t documented. In the documentation it only shows the operator being used before a selector. However, it does work when trying this example in the browswer.

[duncansmart]

Looks like a bug in the older (IE6/7) JScript engine mode which is what WScript uses for old script compatibility. Not sure there's a way of getting WScript to run JScript engine in newer, more standards-compliant mode. Perhaps researching what the differences are between the old and new JScript engine modes will indicate what the issue is in less.js itself so we could submit a patch.

[duncansmart]

Narrows it down http://blogs.msdn.com/b/jscript/archive/2009/04/17/versioning-language-features-in-jscript.aspx

• Native JSON support – This would introduce a new built-in JSON object, and the following built-in methods – JSON.parse(), JSON.stringify(), Date.toJSON(), Number.toJSON(), Boolean.toJSON() and String.toJSON()
• Support for accessor methods for enabling Document Object Model prototypes
• Default the separator to “,” if the separator value is ‘undefined’ in Array.prototype.join
• Return the length of the resultant array instead of ‘undefined’ for Array.prototype.unshift
• Call toString() if precision is ‘undefined’ instead of throwing a “RangeError” for Number.prototype.toPrecision
• Support for array subclassing
• Support for trailing commas in object literals
• Implemented Error.prototype.toString to provide better error messages
• Support for index operator [] on string values

[marklagendijk]

In the article you mention there is a part about: "JScript Versioning in other JScript Hosts (for JScript Host Developers)". Is this something that something that is usable in WScript? If so this would solve our problem. I can't find any documentation on using this in WScript, though.

[duncansmart]

No, don't think so. But based on that list of features worked out that the issue is "index operator [] on string values", or rather lack of it. Just submitting a patch to less.js now...

[marklagendijk]

Cool!

[duncansmart]

Fixed in 622bc45

[duncansmart]

Note: this fix was included in less.js itself by @cloudhead in less/less.js@e808472.

Pull request: less/less.js#452

[marklagendijk]

It is also included in the new release of less.js (1.1.5).