Maybe use a simple <cfcache> tag to eliminate penalty of CF processing on every stylesheet request?

Nesting is hard, yes, but my colleague and I don't like it very much.

Mixins can be achieved with &ltcfsaveoutput>.

CFML is a hammer. :)

Yeah, you can certainly do it that way, but then you incur the penalty of CF processing on every stylesheet request, which can place significant extra load on your server. However, your color manipulation is incorrect, you don't want to divide the whole number by 2, you want to divide each color segment (two-digit pair) by two, and then stitch the results back together.

Doing nesting and inclusion are also problematic with simple output tricks. They really require a full language parser so you can manipulate the AST.

All that said, you could certainly package the couple lines of Ruby up into a custom tag to run your tag body through the interpreter and output it, so a <less:css> tag is really reasonable.

<cfset color = InputBaseN("fdd",16)>

And there were <less:css> on the last example.

##header {
background-color: #FormatBaseN(color, 16)#;
color: #FormatBaseN(color / 2, 16)#;
}

Maybe it'll be a good idea to write a custom tag to do inline LessCss! :)

@color: #fdd;
#header {
background-color: @color;
color: @color / 2;
}

Using a servelet filter is definitely a better approach, and you can still use the Ruby LESS engine via the JSR-223 interface to JRuby in exactly the same way. Obviously you still have to drop JAR, as well as configure the filter, but for JEE-ish applications, it's a no brainer. Where I've used this, I package UrlRewrite to hand off to a CFM file to do the compilation, mostly because I didn't want to have to compile my own Java class.

Yeah, this is a lot of work if all you want is LESS in your CFML app. But if you're already integrating Groovy and Ruby into the app, then all you need is lesscss.cfm somewhere to point at. And this is something that is done per server, so if you're running several applications on a single CF/Railo/OBD instance, you do this once, and all your apps grow support.

Brian