less.php

<?php

/**
 * lessphp v0.2.1
 * http://leafo.net/lessphp
 *
 * LESS css compiler, adapted from http://lesscss.org/docs.html
 *
 * Copyright 2010, Leaf Corcoran <leafot@gmail.com>
 * Licensed under MIT or GPLv3, see LICENSE
 */

/**
 * The less compiler and parser.
 *
 * Converting LESS to CSS is a two stage process. First the incoming document
 * must be parsed. Parsing creates a tree in memory that represents the 
 * structure of the document. Then, the tree of the document is recursively
 * compiled into the CSS text. The compile step has an implicit step called
 * reduction, where values are brought to their lowest form before being
 * turned to text, eg. mathematical equations are solved, and variables are
 * dereferenced.
 *
 * The parsing stage produces the final structure of the document, for this
 * reason mixins are mixed in and attribute accessors are referenced during
 * the parse step. A reduction is done on the mixed in block as it is mixed in.
 *
 *  See the following:
 *    - entry point for parsing and compiling: lessc::parse()
 *    - parsing: lessc::parseChunk()
 *    - compiling: lessc::compileBlock()
 *
 */
class lessc {

    protected $buffer;
    protected $count;
    protected $line;
    public $indentLevel;
    public $indentChar = '  ';
    protected $env = null;
    protected $allParsedFiles = array();
    public $vPrefix = '@'; // prefix of abstract properties
    public $mPrefix = '$'; // prefix of abstract blocks
    public $imPrefix = '!'; // special character to add !important
    public $selfSelector = '&';
    static protected $precedence = array(
        '+' => 0,
        '-' => 0,
        '*' => 1,
        '/' => 1,
        '%' => 1,
    );
    static protected $operatorString; // regex string to match any of the operators
    // types that have delayed computation
    static protected $dtypes = array('expression', 'variable',
        'function', 'negative', 'list', 'lookup');

    /**
     * @link http://www.w3.org/TR/css3-values/
     */
    static protected $units = array(
        'em', 'ex', 'px', 'gd', 'rem', 'vw', 'vh', 'vm', 'ch', // Relative length units
        'in', 'cm', 'mm', 'pt', 'pc', // Absolute length units
        '%', // Percentages
        'deg', 'grad', 'rad', 'turn', // Angles
        'ms', 's', // Times
        'Hz', 'kHz', //Frequencies
    );
    public $importDisabled = false;
    public $importDir = '';
    public $compat = false; // lessjs compatibility mode, does nothing right now

    /**
     * if we are in an expression then we don't need to worry about parsing font shorthand
     * $inExp becomes true after the first value in an expression, or if we enter parens
     */
    protected $inExp = false;

    /**
     * if we are in parens we can be more liberal with whitespace around operators because 
     * it must evaluate to a single value and thus is less ambiguous.
     *
     * Consider:
     *     property1: 10 -5; // is two numbers, 10 and -5
     *     property2: (10 -5); // should evaluate to 5
     */
    protected $inParens = false;

    /**
     * Parse a single chunk off the head of the buffer and place it.
     * @return false when the buffer is empty, or there is an error
     *
     * This functions is called repeatedly until the entire document is
     * parsed.
     *
     * This parser is most similar to a recursive descent parser. Single
     * functions represent discrete grammatical rules for the language, and
     * they are able to capture the text that represents those rules.
     *
     * Consider the function lessc::keyword(). (all parse functions are
     * structured the same)
     *
     * The function takes a single reference argument. When calling the the
     * function it will attempt to match a keyword on the head of the buffer.
     * If it is successful, it will place the keyword in the referenced
     * argument, advance the position in the buffer, and return true. If it
     * fails then it won't advance the buffer and it will return false.
     *
     * All of these parse functions are powered by lessc::match(), which behaves
     * the same way, but takes a literal regular expression. Sometimes it is
     * more convenient to use match instead of creating a new function.
     *
     * Because of the format of the functions, to parse an entire string of
     * grammatical rules, you can chain them together using &&.
     *
     * But, if some of the rules in the chain succeed before one fails, then
     * then buffer position will be left at an invalid state. In order to 
     * avoid this, lessc::seek() is used to remember and set buffer positions.
     *
     * Before doing a chain, use $s = $this->seek() to remember the current
     * position into $s. Then if a chain fails, use $this->seek($s) to 
     * go back where we started.
     */
    function parseChunk() {
        if (empty($this->buffer))
            return false;
        $s = $this->seek();

        // setting a property
        if ($this->keyword($key) && $this->assign() &&
                $this->propertyValue($value) && $this->end()) {
            $this->append(array('assign', $key, $value));
            return true;
        } else {
            $this->seek($s);
        }

        // look for special css blocks
        if ($this->env->parent == null && $this->literal('@', false)) {
            $this->count--;

            // a font-face block
            if ($this->literal('@font-face') && $this->literal('{')) {
                $b = $this->pushSpecialBlock('@font-face');
                return true;
            } else {
                $this->seek($s);
            }

            // charset
            if ($this->literal('@charset') && $this->propertyValue($value) &&
                    $this->end()) {
                $this->append(array('charset', $value));
                return true;
            } else {
                $this->seek($s);
            }


            // media
            if ($this->literal('@media') && $this->mediaTypes($types, $rest) &&
                    $this->literal('{')) {
                $b = $this->pushSpecialBlock('@media');
                $b->media = array($types, $rest);
                return true;
            } else {
                $this->seek($s);
            }

            // css animations
            if ($this->match('(@(-[a-z]+-)?keyframes)', $m) &&
                    $this->propertyValue($value) && $this->literal('{')) {
                $b = $this->pushSpecialBlock(trim($m[0]));
                $b->keyframes = $value;
                return true;
            } else {
                $this->seek($s);
            }
        }

        if (isset($this->env->keyframes)) {
            if ($this->match("(to|from|[0-9]+%)", $m) && $this->literal('{')) {
                $this->pushSpecialBlock($m[1]);
                return true;
            } else {
                $this->seek($s);
            }
        }

        // setting a variable
        if ($this->variable($name) && $this->assign() &&
                $this->propertyValue($value) && $this->end()) {
            $this->append(array('assign', $this->vPrefix . $name, $value));
            return true;
        } else {
            $this->seek($s);
        }

        if ($this->import($url, $media)) {
            // don't check .css files
            if (empty($media) && substr_compare($url, '.css', -4, 4) !== 0) {
                if ($this->importDisabled) {
                    $this->append(array('raw', '/* import disabled */'));
                } else {
                    $path = $this->findImport($url);
                    if (!is_null($path)) {
                        $this->append(array('import', $path));
                        return true;
                    }
                }
            }

            $this->append(array('raw', '@import url("' . $url . '")' .
                ($media ? ' ' . $media : '') . ';'));
            return true;
        }

        // opening parametric mixin
        if ($this->tag($tag, true) && $this->argumentDef($args) &&
                $this->literal('{')) {
            $block = $this->pushBlock($this->fixTags(array($tag)));
            $block->args = $args;
            return true;
        } else {
            $this->seek($s);
        }

        // opening a simple block
        if ($this->tags($tags) && $this->literal('{')) {
            $tags = $this->fixTags($tags);
            $this->pushBlock($tags);
            return true;
        } else {
            $this->seek($s);
        }

        // closing a block
        if ($this->literal('}')) {
            try {
                $block = $this->pop();
            } catch (exception $e) {
                $this->seek($s);
                $this->throwParseError($e->getMessage());
            }

            $hidden = true;
            if (!isset($block->args))
                foreach ($block->tags as $tag) {
                    if ($tag{0} != $this->mPrefix) {
                        $hidden = false;
                        break;
                    }
                }

            if (!$hidden)
                $this->append(array('block', $block));
            foreach ($block->tags as $tag) {
                $this->env->children[$tag] = $block;
            }

            return true;
        }


        // mixin 
        if ($this->tags($tags, true, '>') &&
                ($this->argumentValues($argv) || true) && $this->end()) {
            $tags = $this->fixTags($tags);
            $this->append(array('mixin', $tags, $argv));
            return true;
        } else {
            $this->seek($s);
        }
        // spare ;
        if ($this->literal(';'))
            return true;

        return false; // got nothing, throw error
    }

    function fixTags($tags) {
        // move @ tags out of variable namespace
        foreach ($tags as &$tag) {
            if ($tag{0} == $this->vPrefix)
                $tag[0] = $this->mPrefix;
        }
        return $tags;
    }

    // attempts to find the path of an import url, returns null for css files
    function findImport($url) {
        foreach ((array) $this->importDir as $dir) {
            $full = $dir . (substr($dir, -1) != '/' ? '/' : '') . $url;
            if ($this->fileExists($file = $full . '.less') || $this->fileExists($file = $full)) {
                return $file;
            }
        }

        return null;
    }

    function fileExists($name) {
        // sym link workaround
        return file_exists($name) || file_exists(realpath(preg_replace('/\w+\/\.\.\//', '', $name)));
    }

    // a list of expressions
    function expressionList(&$exps) {
        $values = array();

        while ($this->expression($exp)) {
            $values[] = $exp;
        }

        if (count($values) == 0)
            return false;

        $exps = $this->compressList($values, ' ');
        return true;
    }

    /**
     * Attempt to consume an expression.
     * @link http://en.wikipedia.org/wiki/Operator-precedence_parser#Pseudo-code
     */
    function expression(&$out) {
        $s = $this->seek();
        if ($this->literal('(') && ($this->inExp = $this->inParens = true) && $this->expression($exp) && $this->literal(')')) {
            $lhs = $exp;
        } elseif ($this->seek($s) && $this->value($val)) {
            $lhs = $val;
        } else {
            $this->inParens = $this->inExp = false;
            $this->seek($s);
            return false;
        }

        $out = $this->expHelper($lhs, 0);
        $this->inParens = $this->inExp = false;
        return true;
    }

    /**
     * recursively parse infix equation with $lhs at precedence $minP
     */
    function expHelper($lhs, $minP) {
        $this->inExp = true;
        $ss = $this->seek();

        // if the if there was whitespace before the operator, then we require whitespace after
        // the operator for it to be a mathematical operator.

        $needWhite = false;
        if (!$this->inParens && preg_match('/\s/', $this->buffer{$this->count - 1})) {
            $needWhite = true;
        }

        // try to find a valid operator
        while ($this->match(self::$operatorString . ($needWhite ? '\s' : ''), $m) && self::$precedence[$m[1]] >= $minP) {
            // get rhs
            $s = $this->seek();
            $p = $this->inParens;
            if ($this->literal('(') && ($this->inParens = true) && $this->expression($exp) && $this->literal(')')) {
                $this->inParens = $p;
                $rhs = $exp;
            } else {
                $this->inParens = $p;
                if ($this->seek($s) && $this->value($val)) {
                    $rhs = $val;
                } else {
                    break;
                }
            }

            // peek for next operator to see what to do with rhs
            if ($this->peek(self::$operatorString, $next) && self::$precedence[$next[1]] > $minP) {
                $rhs = $this->expHelper($rhs, self::$precedence[$next[1]]);
            }

            // don't evaluate yet if it is dynamic
            if (in_array($rhs[0], self::$dtypes) || in_array($lhs[0], self::$dtypes))
                $lhs = array('expression', $m[1], $lhs, $rhs);
            else
                $lhs = $this->evaluate($m[1], $lhs, $rhs);

            $ss = $this->seek();

            $needWhite = false;
            if (!$this->inParens && preg_match('/\s/', $this->buffer{$this->count - 1})) {
                $needWhite = true;
            }
        }
        $this->seek($ss);

        return $lhs;
    }

    // consume a list of values for a property
    function propertyValue(&$value) {
        $values = array();

        $s = null;
        while ($this->expressionList($v)) {
            $values[] = $v;
            $s = $this->seek();
            if (!$this->literal(','))
                break;
        }

        if ($s)
            $this->seek($s);

        if (count($values) == 0)
            return false;

        $value = $this->compressList($values, ', ');
        return true;
    }

    // a single value
    function value(&$value) {
        // try a unit
        if ($this->unit($value))
            return true;

        // see if there is a negation
        $s = $this->seek();
        if ($this->literal('-', false) && $this->variable($vname)) {
            $value = array('negative', array('variable', $this->vPrefix . $vname));
            return true;
        } else {
            $this->seek($s);
        }

        // accessor 
        // must be done before color
        // this needs negation too
        if ($this->accessor($a)) {
            $a[1] = $this->fixTags($a[1]);
            $value = $a;
            return true;
        }

        // color
        if ($this->color($value))
            return true;

        // css function
        // must be done after color
        if ($this->func($value))
            return true;

        // string
        if ($this->string($tmp, $d)) {
            $value = array('string', $d . $tmp . $d);
            return true;
        }

        // try a keyword
        if ($this->keyword($word)) {
            $value = array('keyword', $word);
            return true;
        }

        // try a variable
        if ($this->variable($vname)) {
            $value = array('variable', $this->vPrefix . $vname);
            return true;
        }

        return false;
    }

    // an import statement
    function import(&$url, &$media) {
        $s = $this->seek();
        if (!$this->literal('@import'))
            return false;

        // @import "something.css" media;
        // @import url("something.css") media;
        // @import url(something.css) media; 

        if ($this->literal('url('))
            $parens = true; else
            $parens = false;

        if (!$this->string($url)) {
            if ($parens && $this->to(')', $url)) {
                $parens = false; // got em
            } else {
                $this->seek($s);
                return false;
            }
        }

        if ($parens && !$this->literal(')')) {
            $this->seek($s);
            return false;
        }

        // now the rest is media
        return $this->to(';', $media, false, true);
    }

    // a list of media types, very lenient
    function mediaTypes(&$types, &$rest) {
        $s = $this->seek();
        $types = array();
        while ($this->match('([^,{\s]+)', $m)) {
            $types[] = $m[1];
            if (!$this->literal(','))
                break;
        }

        // get everything else
        if ($this->to('{', $rest, true, true)) {
            $rest = trim($rest);
        }

        return count($types) > 0;
    }

    // a scoped value accessor
    // .hello > @scope1 > @scope2['value'];
    function accessor(&$var) {
        $s = $this->seek();

        if (!$this->tags($scope, true, '>') || !$this->literal('[')) {
            $this->seek($s);
            return false;
        }

        // either it is a variable or a property
        // why is a property wrapped in quotes, who knows!
        if ($this->variable($name)) {
            $name = $this->vPrefix . $name;
        } elseif ($this->literal("'") && $this->keyword($name) && $this->literal("'")) {
            // .. $this->count is messed up if we wanted to test another access type
        } else {
            $this->seek($s);
            return false;
        }

        if (!$this->literal(']')) {
            $this->seek($s);
            return false;
        }

        $var = array('lookup', $scope, $name);
        return true;
    }

    // a string 
    function string(&$string, &$d = null) {
        $s = $this->seek();
        if ($this->literal('"', false)) {
            $delim = '"';
        } elseif ($this->literal("'", false)) {
            $delim = "'";
        } else {
            return false;
        }

        if (!$this->to($delim, $string)) {
            $this->seek($s);
            return false;
        }

        $d = $delim;
        return true;
    }

    /**
     * Consume a number and optionally a unit.
     * Can also consume a font shorthand if it is a simple case.
     * $allowed restricts the types that are matched.
     */
    function unit(&$unit, $allowed = null) {
        $simpleCase = $allowed == null;
        if (!$allowed)
            $allowed = self::$units;

        if ($this->match('(-?[0-9]*(\.)?[0-9]+)(' . implode('|', $allowed) . ')?', $m, !$simpleCase)) {
            if (!isset($m[3]))
                $m[3] = 'number';
            $unit = array($m[3], $m[1]);

            // check for size/height font unit.. should this even be here?
            if ($simpleCase) {
                $s = $this->seek();
                if (!$this->inExp && $this->literal('/', false) && $this->unit($right, self::$units)) {
                    $unit = array('keyword', $this->compileValue($unit) . '/' . $this->compileValue($right));
                } else {
                    // get rid of whitespace
                    $this->seek($s);
                    $this->match('', $_);
                }
            }

            return true;
        }

        return false;
    }

    // a # color
    function color(&$out) {
        $color = array('color');

        if ($this->match('(#([0-9a-f]{6})|#([0-9a-f]{3}))', $m)) {
            if (isset($m[3])) {
                $num = $m[3];
                $width = 16;
            } else {
                $num = $m[2];
                $width = 256;
            }

            $num = hexdec($num);
            foreach (array(3, 2, 1) as $i) {
                $t = $num % $width;
                $num /= $width;

                $color[$i] = $t * (256 / $width) + $t * floor(16 / $width);
            }

            $out = $color;
            return true;
        }

        return false;
    }

    // consume a list of property values delimited by ; and wrapped in ()
    function argumentValues(&$args, $delim = ';') {
        $s = $this->seek();
        if (!$this->literal('('))
            return false;

        $values = array();
        while (true) {
            if ($this->propertyValue($value))
                $values[] = $value;
            if (!$this->literal($delim))
                break;
            else {
                if ($value == null)
                    $values[] = null;
                $value = null;
            }
        }

        if (!$this->literal(')')) {
            $this->seek($s);
            return false;
        }

        $args = $values;
        return true;
    }

    // consume an argument definition list surrounded by ()
    // each argument is a variable name with optional value
    function argumentDef(&$args, $delim = ';') {
        $s = $this->seek();
        if (!$this->literal('('))
            return false;

        $values = array();
        while ($this->variable($vname)) {
            $arg = array($vname);
            if ($this->assign() && $this->propertyValue($value)) {
                $arg[] = $value;
                // let the : slide if there is no value
            }

            $values[] = $arg;
            if (!$this->literal($delim))
                break;
        }

        if (!$this->literal(')')) {
            $this->seek($s);
            return false;
        }

        $args = $values;
        return true;
    }

    // consume a list of tags
    // this accepts a hanging delimiter
    function tags(&$tags, $simple = false, $delim = ',') {
        $tags = array();
        while ($this->tag($tt, $simple)) {
            $tags[] = $tt;
            if (!$this->literal($delim))
                break;
        }
        if (count($tags) == 0)
            return false;

        return true;
    }

    // a bracketed value (contained within in a tag definition)
    function tagBracket(&$value) {
        $s = $this->seek();
        if ($this->literal('[') && $this->to(']', $c, true) && $this->literal(']', false)) {
            $value = '[' . $c . ']';
            // whitespace?
            if ($this->match('', $_))
                $value .= $_[0];
            return true;
        }

        $this->seek($s);
        return false;
    }

    // a single tag
    function tag(&$tag, $simple = false) {
        if ($simple)
            $chars = '^,:;{}\][>\(\) ';
        else
            $chars = '^,;{}[';

        $tag = '';
        while ($this->tagBracket($first))
            $tag .= $first;
        while ($this->match('([' . $chars . '0-9][' . $chars . ']*)', $m)) {
            $tag .= $m[1];
            if ($simple)
                break;

            while ($this->tagBracket($brack))
                $tag .= $brack;
        }
        $tag = trim($tag);
        if ($tag == '')
            return false;

        return true;
    }

    // a css function
    function func(&$func) {
        $s = $this->seek();

        if ($this->match('([\w\-_][\w\-_:\.]*)', $m) && $this->literal('(')) {
            $fname = $m[1];
            if ($fname == 'url') {
                $this->to(')', $content, true);
                $args = array('string', $content);
            } else {
                $args = array();
                while (true) {
                    $ss = $this->seek();
                    if ($this->keyword($name) && $this->literal('=') && $this->expressionList($value)) {
                        $args[] = array('list', '=', array(array('keyword', $name), $value));
                    } else {
                        $this->seek($ss);
                        if ($this->expressionList($value)) {
                            $args[] = $value;
                        }
                    }

                    if (!$this->literal(','))
                        break;
                }
                $args = array('list', ',', $args);
            }

            if ($this->literal(')')) {
                $func = array('function', $fname, $args);
                return true;
            }
        }

        $this->seek($s);
        return false;
    }

    // consume a less variable
    function variable(&$name) {
        $s = $this->seek();
        if ($this->literal($this->vPrefix, false) && $this->keyword($name)) {
            return true;
        }

        return false;
    }

    /**
     * Consume an assignment operator
     * Can optionally take a name that will be set to the current property name
     */
    function assign($name = null) {
        if ($name)
            $this->currentProperty = $name;
        return $this->literal(':') || $this->literal('=');
    }

    // consume a keyword
    function keyword(&$word) {
        if ($this->match('([\w_\-\*!"][\w\-_"]*)', $m)) {
            $word = $m[1];
            return true;
        }
        return false;
    }

    // consume an end of statement delimiter
    function end() {
        if ($this->literal(';'))
            return true;
        elseif ($this->count == strlen($this->buffer) || $this->buffer{$this->count} == '}') {
            // if there is end of file or a closing block next then we don't need a ;
            return true;
        }
        return false;
    }

    function compressList($items, $delim) {
        if (count($items) == 1)
            return $items[0];
        else
            return array('list', $delim, $items);
    }

    /**
     * Recursively compiles a block. 
     * @param $block the block
     * @param $parentTags the tags of the block that contained this one
     *
     * A block is analogous to a CSS block in most cases. A single less document
     * is encapsulated in a block when parsed, but it does not have parent tags
     * so all of it's children appear on the root level when compiled.
     *
     * Blocks are made up of props and children.
     *
     * Props are property instructions, array tuples which describe an action
     * to be taken, eg. write a property, set a variable, mixin a block.
     *
     * The children of a block are just all the blocks that are defined within.
     *
     * Compiling the block involves pushing a fresh environment on the stack,
     * and iterating through the props, compiling each one.
     *
     * See lessc::compileProp()
     *
     */
    function compileBlock($block, $parent_tags = null) {
        $isRoot = $parent_tags == null && $block->tags == null;

        $indent = str_repeat($this->indentChar, $this->indentLevel);

        if (!empty($block->no_multiply)) {
            $special_block = true;
            $this->indentLevel++;
            $tags = array();
        } else {
            $special_block = false;
            $tags = $this->multiplyTags($parent_tags, $block->tags);
        }

        $this->pushEnv();
        $lines = array();
        $blocks = array();
        foreach ($block->props as $prop) {
            $this->compileProp($prop, $block, $tags, $lines, $blocks);
        }

        $this->pop();

        $nl = $isRoot ? "\n" . $indent :
                "\n" . $indent . $this->indentChar;

        ob_start();

        if ($special_block) {
            $this->indentLevel--;
            if (isset($block->media)) {
                list($media_types, $media_rest) = $block->media;
                echo "@media " . join(', ', $media_types) .
                (!empty($media_rest) ? " $media_rest" : '' );
            } elseif (isset($block->keyframes)) {
                echo $block->tags[0] . " " .
                $this->compileValue($this->reduce($block->keyframes));
            } else {
                list($name) = $block->tags;
                echo $indent . $name;
            }

            echo ' {' . (count($lines) > 0 ? $nl : "\n");
        }

        // dump it
        if (count($lines) > 0) {
            if (!$special_block && !$isRoot) {
                echo $indent . implode(", ", $tags);
                if (count($lines) > 1)
                    echo " {" . $nl;
                else
                    echo " { ";
            }

            echo implode($nl, $lines);

            if (!$special_block && !$isRoot) {
                if (count($lines) > 1)
                    echo "\n" . $indent . "}\n";
                else
                    echo " }\n";
            } else
                echo "\n";
        }

        foreach ($blocks as $b)
            echo $b;

        if ($special_block) {
            echo $indent . "}\n";
        }

        return ob_get_clean();
    }

    // find the fully qualified tags for a block and its parent's tags
    function multiplyTags($parents, $current) {
        if ($parents == null)
            return $current;

        $tags = array();
        foreach ($parents as $ptag) {
            foreach ($current as $tag) {
                $tags[] = trim($ptag .
                        ($tag{0} == $this->selfSelector || $tag{0} == ':' ? ltrim($tag, $this->selfSelector) : ' ' . $tag));
            }
        }

        return $tags;
    }

    // attempt to find block pointed at by path within search_in or its parent
    function findBlock($search_in, $path) {
        if ($search_in == null)
            return null;
        $name = $path[0];

        if (isset($search_in->children[$name])) {
            $block = $search_in->children[$name];
            if (count($path) == 1) {
                return $block;
            } else {
                return $this->findBlock($block, array_slice($path, 1));
            }
        } else {
            return $this->findBlock($search_in->parent, $path);
        }
    }

    // sets all argument names in $args to either the default value
    // or the one passed in through $values
    function zipSetArgs($args, $values) {
        $i = 0;
        foreach ($args as $a) {
            if ($i < count($values) && !is_null($values[$i])) {
                $value = $values[$i];
            } elseif (isset($a[1])) {
                $value = $a[1];
            } else
                $value = null;

            $this->set($this->vPrefix . $a[0], $this->reduce($value));
            $i++;
        }
    }

    // compile a prop and update $lines or $blocks appropriately
    function compileProp($prop, $block, $tags, &$_lines, &$_blocks) {
        switch ($prop[0]) {
            case 'assign':
                list(, $name, $value) = $prop;
                if ($name[0] == $this->vPrefix) {
                    $this->set($name, $this->reduce($value));
                } else {
                    $_lines[] = "$name:" .
                            $this->compileValue($this->reduce($value)) . ";";
                }
                break;
            case 'block':
                list(, $child) = $prop;
                $_blocks[] = $this->compileBlock($child, $tags);
                break;
            case 'mixin':
                list(, $path, $args) = $prop;

                $mixin = $this->findBlock($block, $path);
                if (is_null($mixin)) {
                    // echo "failed to find block: ".implode(" > ", $path)."\n";
                    break; // throw error here??
                }

                $have_args = false;
                if (isset($mixin->args)) {
                    $have_args = true;
                    $this->pushEnv();
                    $this->zipSetArgs($mixin->args, $args);
                }

                list($name) = $mixin->tags;
                if ($name == "div") {
                    print_r($mixin->props);
                }

                $old_parent = $mixin->parent;
                $mixin->parent = $block;

                foreach ($mixin->props as $sub_prop) {
                    $this->compileProp($sub_prop, $mixin, $tags, $_lines, $_blocks);
                }

                $mixin->parent = $old_parent;

                if ($have_args)
                    $this->pop();

                break;
            case 'raw':
                $_lines[] = $prop[1];
                break;
            case 'import':
                list(, $path) = $prop;
                $this->addParsedFile($path);
                $root = $this->createChild($path)->parseTree();

                $root->parent = $block;
                foreach ($root->props as $sub_prop) {
                    $this->compileProp($sub_prop, $root, $tags, $_lines, $_blocks);
                }

                // inject imported blocks into this block, local will overwrite import
                $block->children = array_merge($root->children, $block->children);
                break;
            case 'charset':
                list(, $value) = $prop;
                $_lines[] = '@charset ' . $this->compileValue($this->reduce($value)) . ';';
                break;
            default:
                echo "unknown op: {$prop[0]}\n";
                throw new exception();
        }
    }

    /**
     * Compiles a primitive value into a CSS property value.
     *
     * Values in lessphp are typed by being wrapped in arrays, their format is
     * typically:
     *
     *     array(type, contents [, additional_contents]*)
     *
     * Will not work on non reduced values (expressions, variables, etc)
     */
    function compileValue($value) {
        switch ($value[0]) {
            case 'list':
                // [1] - delimiter
                // [2] - array of values
                return implode($value[1], array_map(array($this, 'compileValue'), $value[2]));
            case 'keyword':
            // [1] - the keyword 
            case 'number':
                // [1] - the number 
                return $value[1];
            case 'string':
                // [1] - contents of string (includes quotes)
                // search for inline variables to replace
                $replace = array();
                if (preg_match_all('/{(' . $this->preg_quote($this->vPrefix) . '[\w-_][0-9\w-_]*?)}/', $value[1], $m)) {
                    foreach ($m[1] as $name) {
                        if (!isset($replace[$name]))
                            $replace[$name] = $this->compileValue($this->reduce(array('variable', $name)));
                    }
                }
                foreach ($replace as $var => $val) {
                    // strip quotes
                    if (preg_match('/^(["\']).*?(\1)$/', $val)) {
                        $val = substr($val, 1, -1);
                    }
                    $value[1] = str_replace('{' . $var . '}', $val, $value[1]);
                }

                return $value[1];
            case 'color':
                // [1] - red component (either number for a %)
                // [2] - green component
                // [3] - blue component
                // [4] - optional alpha component
                if (count($value) == 5) { // rgba
                    return 'rgba(' . $value[1] . ',' . $value[2] . ',' . $value[3] . ',' . $value[4] . ')';
                }
                return sprintf("#%02x%02x%02x", $value[1], $value[2], $value[3]);
            case 'function':
                // [1] - function name
                // [2] - some value representing arguments
                // see if function evaluates to something else
                $value = $this->reduce($value);
                if ($value[0] == 'function') {
                    return $value[1] . '(' . $this->compileValue($value[2]) . ')';
                }
                else
                    return $this->compileValue($value);
            default: // assumed to be unit	
                return $value[1] . $value[0];
        }
    }

    function lib_rgbahex($color) {
        if ($color[0] != 'color')
            throw new exception("color esperou por valor rgbahex");

        return sprintf("#%02x%02x%02x%02x", isset($color[4]) ? $color[4] * 255 : 0, $color[1], $color[2], $color[3]);
    }

    function lib_quote($arg) {
        return '"' . $this->compileValue($arg) . '"';
    }

    function lib_unquote($arg) {
        $out = $this->compileValue($arg);
        if ($this->quoted($out))
            $out = substr($out, 1, -1);
        return $out;
    }

    // alias for unquote
    function lib_e($arg) {
        return $this->lib_unquote($arg);
    }

    function lib_floor($arg) {
        return floor($arg[1]);
    }

    function lib_round($arg) {
        return round($arg[1]);
    }

    // is a string surrounded in quotes? returns the quoting char if true
    function quoted($s) {
        if (preg_match('/^("|\').*?\1$/', $s, $m))
            return $m[1];
        else
            return false;
    }

    /**
     * Helper function to get argurments for color functions
     * accepts invalid input, non colors interpreted to black
     */
    function colorArgs($args) {
        if ($args[0] != 'list' || count($args[2]) < 2) {
            return array(array('color', 0, 0, 0));
        }
        list($color, $delta) = $args[2];
        if ($color[0] != 'color')
            $color = array('color', 0, 0, 0);

        $delta = floatval($delta[1]);

        return array($color, $delta);
    }

    function lib_darken($args) {
        list($color, $delta) = $this->colorArgs($args);

        $hsl = $this->toHSL($color);
        $hsl[3] = $this->clamp($hsl[3] - $delta, 100);
        return $this->toRGB($hsl);
    }

    function lib_lighten($args) {
        list($color, $delta) = $this->colorArgs($args);

        $hsl = $this->toHSL($color);
        $hsl[3] = $this->clamp($hsl[3] + $delta, 100);
        return $this->toRGB($hsl);
    }

    function lib_saturate($args) {
        list($color, $delta) = $this->colorArgs($args);

        $hsl = $this->toHSL($color);
        $hsl[2] = $this->clamp($hsl[2] + $delta, 100);
        return $this->toRGB($hsl);
    }

    function lib_desaturate($args) {
        list($color, $delta) = $this->colorArgs($args);

        $hsl = $this->toHSL($color);
        $hsl[2] = $this->clamp($hsl[2] - $delta, 100);
        return $this->toRGB($hsl);
    }

    function lib_spin($args) {
        list($color, $delta) = $this->colorArgs($args);

        $hsl = $this->toHSL($color);
        $hsl[1] = $this->clamp($hsl[1] + $delta, 360);
        return $this->toRGB($hsl);
    }

    function lib_fadeout($args) {
        list($color, $delta) = $this->colorArgs($args);
        $color[4] = $this->clamp((isset($color[4]) ? $color[4] : 1) - $delta / 100);
        return $color;
    }

    function lib_fadein($args) {
        list($color, $delta) = $this->colorArgs($args);
        $color[4] = $this->clamp((isset($color[4]) ? $color[4] : 1) + $delta / 100);
        return $color;
    }

    function lib_hue($color) {
        if ($color[0] != 'color')
            return 0;
        $hsl = $this->toHSL($color);
        return round($hsl[1]);
    }

    function lib_saturation($color) {
        if ($color[0] != 'color')
            return 0;
        $hsl = $this->toHSL($color);
        return round($hsl[2]);
    }

    function lib_lightness($color) {
        if ($color[0] != 'color')
            return 0;
        $hsl = $this->toHSL($color);
        return round($hsl[3]);
    }

    function toHSL($color) {
        if ($color[0] == 'hsl')
            return $color;

        $r = $color[1] / 255;
        $g = $color[2] / 255;
        $b = $color[3] / 255;

        $min = min($r, $g, $b);
        $max = max($r, $g, $b);

        $L = ($min + $max) / 2;
        if ($min == $max) {
            $S = $H = 0;
        } else {
            if ($L < 0.5)
                $S = ($max - $min) / ($max + $min);
            else
                $S = ($max - $min) / (2.0 - $max - $min);

            if ($r == $max)
                $H = ($g - $b) / ($max - $min);
            elseif ($g == $max)
                $H = 2.0 + ($b - $r) / ($max - $min);
            elseif ($b == $max)
                $H = 4.0 + ($r - $g) / ($max - $min);
        }

        $out = array('hsl',
            ($H < 0 ? $H + 6 : $H) * 60,
            $S * 100,
            $L * 100,
        );

        if (count($color) > 4)
            $out[] = $color[4]; // copy alpha
        return $out;
    }

    function toRGB_helper($comp, $temp1, $temp2) {
        if ($comp < 0)
            $comp += 1.0;
        elseif ($comp > 1)
            $comp -= 1.0;

        if (6 * $comp < 1)
            return $temp1 + ($temp2 - $temp1) * 6 * $comp;
        if (2 * $comp < 1)
            return $temp2;
        if (3 * $comp < 2)
            return $temp1 + ($temp2 - $temp1) * ((2 / 3) - $comp) * 6;

        return $temp1;
    }

    /**
     * Converts an hsl array into a color value in rgb.
     * Expects H to be in range of 0 to 360, S and L in 0 to 100
     */
    function toRGB($color) {
        if ($color == 'color')
            return $color;

        $H = $color[1] / 360;
        $S = $color[2] / 100;
        $L = $color[3] / 100;

        if ($S == 0) {
            $r = $g = $b = $L;
        } else {
            $temp2 = $L < 0.5 ?
                    $L * (1.0 + $S) :
                    $L + $S - $L * $S;

            $temp1 = 2.0 * $L - $temp2;

            $r = $this->toRGB_helper($H + 1 / 3, $temp1, $temp2);
            $g = $this->toRGB_helper($H, $temp1, $temp2);
            $b = $this->toRGB_helper($H - 1 / 3, $temp1, $temp2);
        }

        $out = array('color', round($r * 255), round($g * 255), round($b * 255));
        if (count($color) > 4)
            $out[] = $color[4]; // copy alpha
        return $out;
    }

    function clamp($v, $max = 1, $min = 0) {
        return min($max, max($min, $v));
    }

    /**
     * Convert the rgb, rgba, hsl color literals of function type
     * as returned by the parser into values of color type.
     */
    function funcToColor($func) {
        $fname = $func[1];
        if ($func[2][0] != 'list')
            return false; // need a list of arguments
        $rawComponents = $func[2][2];

        if ($fname == 'hsl' || $fname == 'hsla') {
            $hsl = array('hsl');
            $i = 0;
            foreach ($rawComponents as $c) {
                $val = $this->reduce($c);
                $val = isset($val[1]) ? floatval($val[1]) : 0;

                if ($i == 0)
                    $clamp = 360;
                elseif ($i < 4)
                    $clamp = 100;
                else
                    $clamp = 1;

                $hsl[] = $this->clamp($val, $clamp);
                $i++;
            }

            while (count($hsl) < 4)
                $hsl[] = 0;
            return $this->toRGB($hsl);
        } elseif ($fname == 'rgb' || $fname == 'rgba') {
            $components = array();
            $i = 1;
            foreach ($rawComponents as $c) {
                $c = $this->reduce($c);
                if ($i < 4) {
                    if ($c[0] == '%')
                        $components[] = 255 * ($c[1] / 100);
                    else
                        $components[] = floatval($c[1]);
                } elseif ($i == 4) {
                    if ($c[0] == '%')
                        $components[] = 1.0 * ($c[1] / 100);
                    else
                        $components[] = floatval($c[1]);
                } else
                    break;

                $i++;
            }
            while (count($components) < 3)
                $components[] = 0;
            array_unshift($components, 'color');
            return $this->fixColor($components);
        }

        return false;
    }

    // reduce a delayed type to its final value
    // dereference variables and solve equations
    function reduce($var, $defaultValue = array('number', 0)) {
        while (in_array($var[0], self::$dtypes)) {
            if ($var[0] == 'list') {
                foreach ($var[2] as &$value)
                    $value = $this->reduce($value);
                break;
            } elseif ($var[0] == 'expression') {
                $var = $this->evaluate($var[1], $var[2], $var[3]);
            } elseif ($var[0] == 'variable') {
                $var = $this->get($var[1]);
            } elseif ($var[0] == 'lookup') {
                // do accessor here....
                $var = array('number', 0);
            } elseif ($var[0] == 'function') {
                $color = $this->funcToColor($var);
                if ($color)
                    $var = $color;
                else {
                    list($_, $name, $args) = $var;
                    $f = array($this, 'lib_' . $name);
                    if (is_callable($f)) {
                        if ($args[0] == 'list')
                            $args = $this->compressList($args[2], $args[1]);

                        $var = call_user_func($f, $this->reduce($args));

                        // convet to a typed value if the result is a php primitive
                        if (is_numeric($var))
                            $var = array('number', $var);
                        elseif (!is_array($var))
                            $var = array('keyword', $var);
                    } else {
                        // plain function, reduce args
                        $var[2] = $this->reduce($var[2]);
                    }
                }
                break; // done reducing after a function
            } elseif ($var[0] == 'negative') {
                $value = $this->reduce($var[1]);
                if (is_numeric($value[1])) {
                    $value[1] = -1 * $value[1];
                }
                $var = $value;
            }
        }

        return $var;
    }

    // evaluate an expression
    function evaluate($op, $left, $right) {
        $left = $this->reduce($left);
        $right = $this->reduce($right);

        if ($left[0] == 'color' && $right[0] == 'color') {
            $out = $this->op_color_color($op, $left, $right);
            return $out;
        }

        if ($left[0] == 'color') {
            return $this->op_color_number($op, $left, $right);
        }

        if ($right[0] == 'color') {
            return $this->op_number_color($op, $left, $right);
        }

        // concatenate strings
        if ($op == '+' && $left[0] == 'string') {
            $append = $this->compileValue($right);
            if ($this->quoted($append))
                $append = substr($append, 1, -1);

            $lhs = $this->compileValue($left);
            if ($q = $this->quoted($lhs))
                $lhs = substr($lhs, 1, -1);
            if (!$q)
                $q = '';

            return array('string', $q . $lhs . $append . $q);
        }

        if ($left[0] == 'keyword' || $right[0] == 'keyword' ||
                $left[0] == 'string' || $right[0] == 'string') {
            // look for negative op
            if ($op == '-')
                $right[1] = '-' . $right[1];
            return array('keyword', $this->compileValue($left) . ' ' . $this->compileValue($right));
        }

        // default to number operation
        return $this->op_number_number($op, $left, $right);
    }

    // make sure a color's components don't go out of bounds
    function fixColor($c) {
        foreach (range(1, 3) as $i) {
            if ($c[$i] < 0)
                $c[$i] = 0;
            if ($c[$i] > 255)
                $c[$i] = 255;
            $c[$i] = floor($c[$i]);
        }

        return $c;
    }

    function op_number_color($op, $lft, $rgt) {
        if ($op == '+' || $op = '*') {
            return $this->op_color_number($op, $rgt, $lft);
        }
    }

    function op_color_number($op, $lft, $rgt) {
        if ($rgt[0] == '%')
            $rgt[1] /= 100;

        return $this->op_color_color($op, $lft, array_fill(1, count($lft) - 1, $rgt[1]));
    }

    function op_color_color($op, $left, $right) {
        $out = array('color');
        $max = count($left) > count($right) ? count($left) : count($right);
        foreach (range(1, $max - 1) as $i) {
            $lval = isset($left[$i]) ? $left[$i] : 0;
            $rval = isset($right[$i]) ? $right[$i] : 0;
            switch ($op) {
                case '+':
                    $out[] = $lval + $rval;
                    break;
                case '-':
                    $out[] = $lval - $rval;
                    break;
                case '*':
                    $out[] = $lval * $rval;
                    break;
                case '%':
                    $out[] = $lval % $rval;
                    break;
                case '/':
                    if ($rval == 0)
                        throw new exception("evaluate error: nao se pode dividir por zero!");
                    $out[] = $lval / $rval;
                    break;
                default:
                    throw new exception('evaluate error: color op number failed on op ' . $op);
            }
        }
        return $this->fixColor($out);
    }

    // operator on two numbers
    function op_number_number($op, $left, $right) {
        if ($right[0] == '%')
            $right[1] /= 100;

        // figure out type
        if ($right[0] == 'number' || $right[0] == '%')
            $type = $left[0];
        else
            $type = $right[0];

        $value = 0;
        switch ($op) {
            case '+':
                $value = $left[1] + $right[1];
                break;
            case '*':
                $value = $left[1] * $right[1];
                break;
            case '-':
                $value = $left[1] - $right[1];
                break;
            case '%':
                $value = $left[1] % $right[1];
                break;
            case '/':
                if ($right[1] == 0)
                    throw new exception('parse error: divide by zero');
                $value = $left[1] / $right[1];
                break;
            default:
                throw new exception('parse error: unknown number operator: ' . $op);
        }

        return array($type, $value);
    }

    /* environment functions */

    // push a new block on the stack, used for parsing
    function pushBlock($tags) {
        $b = new stdclass;
        $b->parent = $this->env;

        $b->tags = $tags;
        $b->props = array();
        $b->children = array();

        $this->env = $b;
        return $b;
    }

    // push a block that doesn't multiply tags
    function pushSpecialBlock($name) {
        $b = $this->pushBlock(array($name));
        $b->no_multiply = true;
        return $b;
    }

    // used for compiliation variable state
    function pushEnv() {
        $e = new stdclass;
        $e->parent = $this->env;

        $this->store = array();

        $this->env = $e;
        return $e;
    }

    // pop something off the stack
    function pop() {
        $old = $this->env;
        $this->env = $this->env->parent;
        return $old;
    }

    // set something in the current env
    function set($name, $value) {
        $this->env->store[$name] = $value;
    }

    // append an property
    function append($prop) {
        $this->env->props[] = $prop;
    }

    // get the highest occurrence entry for a name
    function get($name) {
        $current = $this->env;
        while ($current) {
            if (isset($current->store[$name]))
                return $current->store[$name];
            else
                $current = $current->parent;
        }

        return null;
    }

    /* raw parsing functions */

    function literal($what, $eatWhitespace = true) {
        // this is here mainly prevent notice from { } string accessor 
        if ($this->count >= strlen($this->buffer))
            return false;

        // shortcut on single letter
        if (!$eatWhitespace and strlen($what) == 1) {
            if ($this->buffer{$this->count} == $what) {
                $this->count++;
                return true;
            }
            else
                return false;
        }

        return $this->match($this->preg_quote($what), $m, $eatWhitespace);
    }

    function preg_quote($what) {
        return preg_quote($what, '/');
    }

    // advance counter to next occurrence of $what
    // $until - don't include $what in advance
    function to($what, &$out, $until = false, $allowNewline = false) {
        $validChars = $allowNewline ? "[^\n]" : '.';
        if (!$this->match('(' . $validChars . '*?)' . $this->preg_quote($what), $m, !$until))
            return false;
        if ($until)
            $this->count -= strlen($what); // give back $what
        $out = $m[1];
        return true;
    }

    // try to match something on head of buffer
    function match($regex, &$out, $eatWhitespace = true) {
        $r = '/' . $regex . ($eatWhitespace ? '\s*' : '') . '/Ais';
        if (preg_match($r, $this->buffer, $out, null, $this->count)) {
            $this->count += strlen($out[0]);
            return true;
        }
        return false;
    }

    // match something without consuming it
    function peek($regex, &$out = null) {
        $r = '/' . $regex . '/Ais';
        $result = preg_match($r, $this->buffer, $out, null, $this->count);

        return $result;
    }

    // seek to a spot in the buffer or return where we are on no argument
    function seek($where = null) {
        if ($where === null)
            return $this->count;
        else
            $this->count = $where;
        return true;
    }

    /**
     * Initialize state for a fresh parse
     */
    protected function prepareParser($buff) {
        $this->env = null;
        $this->expandStack = array();
        $this->indentLevel = 0;
        $this->count = 0;
        $this->line = 1;

        $this->buffer = $this->removeComments($buff);
        $this->pushBlock(null); // set up global scope
        // trim whitespace on head
        if (preg_match('/^\s+/', $this->buffer, $m)) {
            $this->line += substr_count($m[0], "\n");
            $this->buffer = ltrim($this->buffer);
        }
    }

    // create a child parser (for compiling an import)
    protected function createChild($fname) {
        $less = new lessc($fname);
        $less->importDir = $this->importDir;
        $less->indentChar = $this->indentChar;
        $less->compat = $this->compat;
        return $less;
    }

    // parse code and return intermediate tree
    public function parseTree($str = null) {
        $this->prepareParser(is_null($str) ? $this->buffer : $str);
        while (false !== $this->parseChunk());

        if ($this->count != strlen($this->buffer))
            $this->throwParseError();

        if (!is_null($this->env->parent))
            throw new exception('parse error: unclosed block');

        $root = $this->env;
        $this->env = null;
        return $root;
    }

    // inject array of unparsed strings into environment as variables
    protected function injectVariables($args) {
        $this->pushEnv();
        $parser = new lessc();
        foreach ($args as $name => $str_value) {
            if ($name{0} != '@')
                $name = '@' . $name;
            $parser->count = 0;
            $parser->buffer = (string) $str_value;
            if (!$parser->propertyValue($value)) {
                throw new Exception("failed to parse passed in variable $name: $str_value");
            }

            $this->set($name, $value);
        }
    }

    // parse and compile buffer
    function parse($str = null, $initial_variables = null) {
        $locale = setlocale(LC_NUMERIC, 0);
        setlocale(LC_NUMERIC, "C");
        $root = $this->parseTree($str);

        if ($initial_variables)
            $this->injectVariables($initial_variables);
        $out = $this->compileBlock($root);
        setlocale(LC_NUMERIC, $locale);
        return $out;
    }

    function throwParseError($msg = 'parse error') {
        $line = $this->line + substr_count(substr($this->buffer, 0, $this->count), "\n");
        if (isset($this->fileName)) {
            $loc = $this->fileName . ' on line ' . $line;
        } else {
            $loc = "line: " . $line;
        }

        if ($this->peek("(.*?)(\n|$)", $m))
            throw new exception($msg . ': falhou em `' . $m[1] . '` ' . $loc);
    }

    /**
     * Initialize any static state, can initialize parser for a file
     */
    function __construct($fname = null, $opts = null) {
        if (!self::$operatorString) {
            self::$operatorString =
                    '(' . implode('|', array_map(array($this, 'preg_quote'), array_keys(self::$precedence))) . ')';
        }

        if ($fname) {
            if (!is_file($fname)) {
                throw new Exception('load error: Nao foi possivel encontrar ' . $fname);
            }
            $pi = pathinfo($fname);

            $this->fileName = $fname;
            $this->importDir = $pi['dirname'] . '/';
            $this->buffer = file_get_contents($fname);

            $this->addParsedFile($fname);
        }
    }

    // remove comments from $text
    // todo: make it work for all functions, not just url
    function removeComments($text) {
        $look = array(
            'url(', '//', '/*', '"', "'"
        );

        $out = '';
        $min = null;
        $done = false;
        while (true) {
            // find the next item
            foreach ($look as $token) {
                $pos = strpos($text, $token);
                if ($pos !== false) {
                    if (!isset($min) || $pos < $min[1])
                        $min = array($token, $pos);
                }
            }

            if (is_null($min))
                break;

            $count = $min[1];
            $skip = 0;
            $newlines = 0;
            switch ($min[0]) {
                case 'url(':
                    if (preg_match('/url\(.*?\)/', $text, $m, 0, $count))
                        $count += strlen($m[0]) - strlen($min[0]);
                    break;
                case '"':
                case "'":
                    if (preg_match('/' . $min[0] . '.*?' . $min[0] . '/', $text, $m, 0, $count))
                        $count += strlen($m[0]) - 1;
                    break;
                case '//':
                    $skip = strpos($text, "\n", $count);
                    if ($skip === false)
                        $skip = strlen($text) - $count;
                    else
                        $skip -= $count;
                    break;
                case '/*':
                    if (preg_match('/\/\*.*?\*\//s', $text, $m, 0, $count)) {
                        $skip = strlen($m[0]);
                        $newlines = substr_count($m[0], "\n");
                    }
                    break;
            }

            if ($skip == 0)
                $count += strlen($min[0]);

            $out .= substr($text, 0, $count) . str_repeat("\n", $newlines);
            $text = substr($text, $count + $skip);

            $min = null;
        }

        return $out . $text;
    }

    public function allParsedFiles() {
        return $this->allParsedFiles;
    }

    protected function addParsedFile($file) {
        $this->allParsedFiles[realpath($file)] = filemtime($file);
    }

    // compile to $in to $out if $in is newer than $out
    // returns true when it compiles, false otherwise
    public static function ccompile($in, $out) {
        if (!is_file($out) || filemtime($in) > filemtime($out)) {
            $less = new lessc($in);
            file_put_contents($out, $less->parse());
            return true;
        }

        return false;
    }

    /**
     * Execute lessphp on a .less file or a lessphp cache structure
     * 
     * The lessphp cache structure contains information about a specific
     * less file having been parsed. It can be used as a hint for future
     * calls to determine whether or not a rebuild is required.
     * 
     * The cache structure contains two important keys that may be used
     * externally:
     * 
     * compiled: The final compiled CSS
     * updated: The time (in seconds) the CSS was last compiled
     * 
     * The cache structure is a plain-ol' PHP associative array and can
     * be serialized and unserialized without a hitch.
     * 
     * @param mixed $in Input
     * @param bool $force Force rebuild?
     * @return array lessphp cache structure
     */
    public static function cexecute($in, $force = false) {

        // assume no root
        $root = null;

        if (is_string($in)) {
            $root = $in;
        } elseif (is_array($in) and isset($in['root'])) {
            if ($force or !isset($in['files'])) {
                // If we are forcing a recompile or if for some reason the
                // structure does not contain any file information we should
                // specify the root to trigger a rebuild.
                $root = $in['root'];
            } elseif (isset($in['files']) and is_array($in['files'])) {
                foreach ($in['files'] as $fname => $ftime) {
                    if (!file_exists($fname) or filemtime($fname) > $ftime) {
                        // One of the files we knew about previously has changed
                        // so we should look at our incoming root again.
                        $root = $in['root'];
                        break;
                    }
                }
            }
        } else {
            // TODO: Throw an exception? We got neither a string nor something
            // that looks like a compatible lessphp cache structure.
            return null;
        }

        if ($root !== null) {
            // If we have a root value which means we should rebuild.
            $less = new lessc($root);
            $out = array();
            $out['root'] = $root;
            $out['compiled'] = $less->parse();
            $out['files'] = $less->allParsedFiles();
            $out['updated'] = time();
            return $out;
        } else {
            // No changes, pass back the structure
            // we were given initially.
            return $in;
        }
    }

}

try {
    if ($handle = opendir('./less')) {
        while (false !== ($file = readdir($handle))) {
            if ($file != "." && $file != ".." && strpos($file, '_') !== 0) {
                $file = str_replace('.less', '', $file);
                lessc::ccompile("./less/$file.less", "./css/$file.css");
                echo "$file.less compilado.<br>";
            }
        }
        closedir($handle);
    }
    die('ok!');
} catch (exception $ex) {
    exit($ex->getMessage());
}