What does "forceCompile" mean on YII when you use Less? - yii

Question

I have this:
'components'=>array(
'less'=>array(
'class'=>'ext.less.components.LessCompiler',
'forceCompile'=> true, //YII_DEBUG, // indicates whether to force compiling
//'compress'=>false, // indicates whether to compress compiled CSS
//'debug'=>false, // indicates whether to enable compiler debugging mode
'paths'=>array(
'less/style.less'=>'css/style.css',
),
),
If I enable forceCompile my site is extremely slow. I would imagine because it regenerates the css on each page load. My question is around disabling it. If I disable it:
Will any changes I make to style.less not reflect in the browser?
If so, what is the point of Less? Surely it can't actually be used in production then? Or do you disable forceCompile so it only generates it once?
Any clarity on forceCompile would be highly appreciated!
(And yes, I looked all of for a clear explanation... best I could find was this).

Answer 1

First let me tell you what is the point of less:
less is a meta language, so in general terms using less helps you write easily maintainable css, although the "language" used is less syntax. As a common example, you can define variables in less that are compiled to css values according to the other statements in your less file. Or you can use mixins, nesting, inheritance concepts like you would in most other languages that support OOP.
So you write understandable, readable pseudo/meta css code that is converted to actual css upon compilation.
Now the extension:
Even if you disable forceCompile, the changes made in style.less should reflect, because the extension checks if the file was modified (the following lines from LessCompiler.php should convince you about that):
if ($this->forceCompile || $this->hasChanges())
$this->compileAll();
// ...
/**
* Returns whether any of files configured to be compiled has changed.
* #return boolean the result.
*/
protected function hasChanges() {
// ...
$compiled = $this->getLastModified($destination);
// ...
$modified = $this->getLastModified($dir);
// ...
}
/**
* Returns the last modified for a specific path.
* #param string $path the path.
* #return integer the last modified (as a timestamp).
*/
protected function getLastModified($path){
//...
}
So forceCompile will always compile the file(s) you specify in paths, and you should not enable it in production. The hasChanges call should take care of less files that have been modified, and compile them, which as you see above is automatically done by the extension.