Source lines noting & Minification

[beseg]

It would be nice (and useful) if in the output file, before each line will be its sources-lines, in the .less files. Also it would be nice if the output file will be minified.
I think it should be an option while compiling (something ilke: 0 - minified mode, 1 (default) - regular mode, 2 - explain-sources mode).

When I'm talking about sources-line noting, I'm thinking on somthing like that (from the homepage example):

/* source.less : 4 */
.underline { border-bottom:1px solid green; }
/* source.less : 13, 4 */
#header .navigation a { border-bottom:1px solid green; }
/* source.less : 11, 1 */
#header .navigation { font-size:12px; }
/* source.less : 18 */
#header .logo:hover { text-decoration:none; }
/* source.less : 17 */
#header .logo { width:300px; }
#header {
  /* source.less : 7 */
  color:black;
  /* source.less : 8, 2 */
  border:1px solid #dd44dd;
}

(the same should be done if there are multiple .less files involving; file-name + line-number for each source-line)

I've tried to check how to do it myself, but I've no idea how to dive in the code...

[xdissent]

Yeah but what happens if the LESS source is manipulated on the fly before parsing. The @import() statement is already half crippled if you're not parsing LESS directly from the filesystem, so this feature would have to follow suit there. I do like the minified option, and I've been planning to add it to my own LESS workflow at some point. Of course, the minified output would be the same regardless of whether or not the LESS was loaded and compiled directly from the FS, so it makes a little more sense.

[jtousek]

well not bad idea but personly i use either cssviewer or firebug... however as an option for debuging porposes only it's not bad

[xdissent]

I mean, with mixins being called left and right, and imports, and imports with mixins, and dynamic LESS generated by PHP, this is going to be a behemoth of a feature now that I think about it. Right?

[johncrenshaw]

Looking at the code, this actually looks fairly straightforward. Just call $this->set("__line", $this->line); each time a new tag is encountered and use the line during compilation to build the comment.

For non-file inputs, add an optional "file" parameter to parse(). (This is needed anyway.)

For import, only a minor tweak is needed (to change it to the way it should have been anyway.)

1. Save a copy of the current line and file
2. Parse the import file data via $this->parse($loaded, $url); (rather than adding it to the current buffer).
3. Restore the original line and file data

Also, there is already a firebug plugin that consumes file/line metadata in SASS files. If the output for this feature matched the output used by SASS, and consumed by that plugin, it would be infinitely more useful.

[ogorzalka]

i think it would be great to make something like sass which uses this syntax on each selector :

@media -sass-debug-info{filename{font-family:file\:\/\/C\:\\wamp\\www\\test\\\\css\\styles\.scss;}line{font-family:'2334';}}
.test a {
     color:blue;
}

It would be easy to edit the firesass extension so that it can work with less...

[xomba]

The line number in a prepended comment will help when reading the raw output file, but does little for you in Firebug. If the line number was added as a class to each rule when in a development mode, it would be easy to spot in tools like Firebug.

For example:
.foo { color: #FFF; }

becomes:
.foo, .line-351 { color: #FFF; }

[jtousek]

xomba: Bad idea. This would stop ::-moz-selection pseudo-element from working. Another thing is that it wouldn't be very helpful with mixins.

[johncrenshaw]

Xomba's idea is good enough for most cases, and it has the distinct advantage of getting the data into debug consoles without requiring any additional plugins, so I looked into what it requires just to hack in. Turns out to be absurdly easy:

In lesc_parser::pushBlock(), add:
if ($tags && $this->lessc->debug_info) { $count = is_null($count) ? $this->count : $count; $line = $this->line + substr_count(substr($this->buffer, 0, $count), "\n"); $b->line = $line; $b->fileName = $this->lessc->fileName; }

Then in lessc::compileBlock(), just before the return, add:
if ($tags && $this->debug_info && isset($block->line) && isset($block->fileName)) { $tags[] = '.lessc_debug_info[line="'.$block->line.'"][file="'.basename($block->fileName).'"]'; }

The first edit is needed for any sort of solution here

Issues:

• Line number finding uses the same method as the error handler, which in this case is now horribly inefficient. It would be far better to maintain the current line number as the position indicator ($this->count) is updated.
• Line number is the line where the block is defined. If you need more detailed information, like info about mixins, you'd have to dig deeper on your own. The line number of the block should give a sufficient starting point for this though.