public function compile($env, $args = NULL, $important = NULL)
{
$_arguments = array();
$mixinFrames = array_merge($this->frames, $env->frames);
$mixinEnv = new Less_Environment();
$mixinEnv->addFrames($mixinFrames);
$frame = $this->compileParams($env, $mixinEnv, $args, $_arguments);
$ex = new Less_Tree_Expression($_arguments);
array_unshift($frame->rules, new Less_Tree_Rule('@arguments', $ex->compile($env)));
$rules = $important ? Less_Tree_Ruleset::makeImportant($this->selectors, $this->rules)->rules : array_slice($this->rules, 0);
$ruleset = new Less_Tree_Ruleset(null, $rules);
// duplicate the environment, adding new frames.
$ruleSetEnv = new Less_Environment();
$ruleSetEnv->addFrame($this);
$ruleSetEnv->addFrame($frame);
$ruleSetEnv->addFrames($mixinFrames);
$ruleSetEnv->compress = $env->compress;
$ruleset = $ruleset->compile($ruleSetEnv);
$ruleset->originalRuleset = $this;
return $ruleset;
}