oyejorge · oyejorge · May 3, 2014 · Apr 13, 2014 · Apr 13, 2014 · Apr 13, 2014
diff --git a/lib/Less/Environment.php b/lib/Less/Environment.php
@@ -47,6 +47,11 @@ class Less_Environment{
 
 	public static $mixin_stack = 0;
 
+	/**
+	 * @var array
+	 */
+	public $functions = array();
+
 
 	public function Init(){
 

diff --git a/lib/Less/Parser.php b/lib/Less/Parser.php
@@ -139,7 +139,25 @@ public function SetOption($option,$value){
 		Less_Parser::$options[$option] = $value;
 	}
 
+	/**
+	 * Registers a new custom function
+	 *
+	 * @param  string   $name     function name
+	 * @param  callable $callback callback
+	 */
+	public function registerFunction($name, $callback) {
+		$this->env->functions[$name] = $callback;
+	}
 
+	/**
+	 * Removed an already registered function
+	 *
+	 * @param  string $name function name
+	 */
+	public function unregisterFunction($name) {
+		if( isset($this->env->functions[$name]) )
+			unset($this->env->functions[$name]);
+	}
 
 
 	/**

diff --git a/lib/Less/Tree/Call.php b/lib/Less/Tree/Call.php
@@ -79,6 +79,12 @@ public function compile($env=null){
 				} catch (Exception $e) {
 					throw new Less_Exception_Compiler('error evaluating function `' . $this->name . '` '.$e->getMessage().' index: '. $this->index);
 				}
+			} elseif( isset( $env->functions[$nameLC] ) && is_callable( $env->functions[$nameLC] ) ) {
+				try {
+					$result = call_user_func_array( $env->functions[$nameLC], $args );
+				} catch (Exception $e) {
+					throw new Less_Exception_Compiler('error evaluating function `' . $this->name . '` '.$e->getMessage().' index: '. $this->index);
+				}
 			}
 		}
 

diff --git a/test/Fixtures/functions/css/f1.css b/test/Fixtures/functions/css/f1.css
@@ -0,0 +1,3 @@
+body:before {
+  content: '0987654321';
+}
diff --git a/test/Fixtures/functions/less/f1.less b/test/Fixtures/functions/less/f1.less
@@ -0,0 +1,3 @@
+body:before {
+	content: myfunc-reverse('1234567890');
+}
diff --git a/test/phpunit/FunctionTest.php b/test/phpunit/FunctionTest.php
@@ -0,0 +1,29 @@
+<?php
+
+class phpunit_FunctionTest extends phpunit_bootstrap{
+	/**
+	 * Test
+	 */
+	public function testFunction() {
+		echo "\nBegin Tests";
+
+		$less_file = $this->fixtures_dir.'/functions/less/f1.less';
+		$expected_css = file_get_contents( $this->fixtures_dir.'/functions/css/f1.css' );
+
+		$parser = new Less_Parser();
+
+		$parser->registerFunction( 'myfunc-reverse', array( __CLASS__, 'reverse' ) );
+
+		$parser->parseFile( $less_file );
+		$generated_css = $parser->getCss();
+
+		$this->assertEquals( $expected_css, $generated_css );
+	}
+
+	public static function reverse( $arg ) {
+		if( is_a( $arg, 'Less_Tree_Quoted' ) ) {
+			$arg->value = strrev( $arg->value );
+			return $arg;
+		}
+	}
+}