SamsonGame/utils/jsm.inc.php

<?php

class JSM
{
  //NOTE: parsed modules are shared between JSM instances
  static private $modules = array();
  static private $consts = array();

  private $base_dir;
  private $file;
  private $scope_vars = array(array());
  private $includes = array();
  private $defs = array();
  private $buffers = array();
  private $nodes = array();
  private $cur_modules = array();
  private $args_parser;

  function __construct($base_dir, $file)
  {
    //for rand constants
    mt_srand();

    $this->base_dir = rtrim(jsm_normalize_path($base_dir, true/*nix*/), '/');
    $this->file = $file;
    $this->args_parser = new JSM_ArgsParser();
  }

  function getRootFile()
  {
    return $this->file;
  }

  function getModule($file)
  {
    if(isset(self::$modules[$file]))
      return self::$modules[$file];
    throw new Exception("Module for '$file' not found");
  }

  function _extractModule($file)
  {
    $txt = file_get_contents($file);
    if($txt === false)
      throw new Exception("Bad file '{$file}'");

    $m = new JSM_Module($file);

    $m->node = new JSM_MacroDefNode($file/*using file as name*/);
    $this->_pushCurrentModule($m);

    $txt = $this->_fixJunk($txt);
    $txt = $this->_processIncludes($file, $txt);
    $txt = $this->_removeBlockComments($txt);
    $txt = $this->_removeLineComments($txt);
    $txt = $this->_extractScriptDefs($file, $txt);
    $this->_parseDefBody($m->node, $file, $txt);

    $this->_popCurrentModule();

    return $m;
  }

  function _pushCurrentModule(JSM_Module $m)
  {
    $this->cur_modules[] = $m;
  }

  function _popCurrentModule()
  {
    if(!$this->cur_modules)
      throw new Exception("No module to pop");
    $m = array_pop($this->cur_modules);
    return $m;
  }

  function _currentModule()
  {
    $m = end($this->cur_modules);
    if(!$m)
      throw new Exception("No current modules");
    return $m;
  }

  function getCurrentModule()
  {
    return $this->_currentModule();
  }

  function process()
  {
    $m = $this->_extractModule($this->file);

    if($this->cur_modules)
      throw new Exception("Non closed modules");

    $this->defs = $m->defs;
    $this->includes = $m->includes;

    $this->_pushBuffer();
    $m->node->call($this);
    $res = $this->_popBuffer();

    if($this->buffers)
      throw new Exception("Non closed buffers " . sizeof($this->buffers));

    if($this->nodes)
      throw new Exception("Non closed nodes " . sizeof($this->nodes));

    $res = $this->_processRelpaths($this->file, $res);
    return array($res, $m);
  }

  function _pushNode(JSM_MacroInternalNode $n)
  {
    $this->nodes[] = $n;
  }

  function _popNode()
  {
    if(!$this->nodes)
      throw new Exception("No nodes to pop");
    $n = array_pop($this->nodes);
    return $n;
  }

  function _node($strict = true)
  {
    $n = end($this->nodes);
    if(!$n)
    {
      if($strict)
        throw new Exception("No current node");
      else 
        return null;
    }
    return $n;
  }

  function _pushBuffer()
  {
    $this->buffers[] = new JSM_TextBuffer();
  }

  function _popBuffer()
  {
    if(!$this->buffers)
      throw new Exception("No buffers to pop");
    $b = array_pop($this->buffers);
    return $b->getContent();
  }

  function _buffer()
  {
    $b = end($this->buffers);
    if(!$b)
      throw new Exception("No current buffer");
    return $b;
  }

  function _pushVarScope()
  {
    $this->scope_vars[] = array();
  }

  function _popVarScope()
  {
    array_pop($this->scope_vars);
  }

  function setConst($name, $value)
  {
    if(isset(self::$consts[$name]) && self::$consts[$name] != $value)
    {
      $curr_value = self::$consts[$name];
      throw new Exception("Const '$name' is already defined as {$curr_value}");
    }
    self::$consts[$name] = $value;
  }

  function hasConst($name, $value)
  {
    return isset(self::$consts[$name]);
  }

  function getConst($name)
  {
    if(!isset(self::$consts[$name]))
      throw new Exception("Const '$name' is not defined");

    return self::$consts[$name];
  }

  function getAutoConst($name)
  {
    if(!isset(self::$consts[$name]))
      $this->setConst($name, crc32($name) & 0xFFFFFFF);

    return $this->getConst($name);
  }

  function setVar($name, $value)
  {
    $this->scope_vars[sizeof($this->scope_vars) - 1][$name] = $value;
  }

  function getVar($name)
  {
    $vars = end($this->scope_vars);
    if(isset($vars[$name]))
      return $vars[$name];
    throw new Exception("Var '$name' not resolved");
  }

  function getVarAnyScope($name)
  {
    for($i=count($this->scope_vars) - 1; $i>=0; --$i)
    {
      $vars = $this->scope_vars[$i];
      if(isset($vars[$name]))
        return $vars[$name];
    }
    throw new Exception("Var '$name' not resolved");
  }

  private function _fixJunk($txt)
  {
    //windows eol
    $txt = str_replace("\r\n", "\n", $txt);
    return $txt;
  }

  private function _removeBlockComments($txt)
  {
    if(strpos($txt, '/*') === false)
      return $txt;
    $regex = '~/\*.*?\*/~s';
    $txt = preg_replace_callback(
      $regex, 
      //preserve the new lines for better error reporting
      function($m) { return str_repeat("\n", substr_count($m[0], "\n")); },
      $txt);
    return $txt;
  }

  private function _removeLineComments($txt)
  {
    //TODO: it's not robust enough, note a hack for URL addresses
    $txt = preg_replace("~\s*(?<!:)//.*~", "\n", $txt);
    return $txt;
  }

  /*private */function _relpathCallback(array $m, $curr_dir)
  {
    //1) checking if such a file exists and normalizing all .. in the path
    $full_path = realpath($curr_dir . '/' . $m[1]);
    if(!$full_path)
      throw new Exception("Bad relative path '$m[1]'");
    //2) now turning the path into *nix alike
    $full_path = jsm_normalize_path($full_path, true/*nix*/);
    $rel_path = ltrim(str_replace($this->base_dir, '', $full_path), '/');

    return $rel_path;
  }

  /*private */function _relconfCallback(array $m, $curr_dir)
  {
    //1) checking if such a file exists and normalizing all .. in the path
    $full_path = realpath($curr_dir . '/' . $m[1] . '.conf.js');
    if(!$full_path)
      throw new Exception("Bad relative path '$m[1]'" . ($curr_dir . '/' . $m[1]));

    $full_path = jsm_normalize_path($full_path, true/*nix*/);
    $rel_path = ltrim(str_replace($this->base_dir, '', $full_path), '/');
    $rel_path = str_replace('.conf.js', '', $rel_path);

    return "@$rel_path";
  }

  private function _processRelpaths($file, $txt)
  {
    //normalizing all file paths
    if(strpos($txt, './') !== false)
    {
      $curr_dir = dirname($file);
      $self = $this;
      $txt = preg_replace_callback(
        '~\./((.*?)\.(jpg|jpeg|swf|png|mp3|txt|gif|ogg))~', 
        function($m) use($self, $curr_dir) { return $self->_relpathCallback($m, $curr_dir); }, 
        $txt);
      $txt = preg_replace_callback(
        '~@\./([^"]+)~', 
        function($m) use($self, $curr_dir) { return $self->_relconfCallback($m, $curr_dir); }, 
        $txt);
    }
    return $txt;
  }

  /*private */function _includesCallback(array $m, $curr_file)
  {
    $file_name = $m[1];
    $dir = ($file_name[0] == '/') ? $this->base_dir : dirname($curr_file);
    $file = jsm_normalize_path($dir . '/' . $m[1]);

    $cm = $this->_currentModule(); 

    if(!isset(self::$modules[$file]))
    {
      if($this->_hasExtension($file, '.js'))
      {
        self::$modules[$file] = $this->_extractModule($file);
      }
      else if($this->_hasExtension($file, '.php'))
      {
        include_once($file);
        //special mark for PHP include
        self::$modules[$file] = 1;
      }
      else
        throw new Exception("Unknown extension of the include file '$file'");
    }

    $m = self::$modules[$file]; 
    $need_include_macro = false;
    //NOTE: module can be non object if it's a PHP include
    if(is_object($m))
    {
      $need_include_macro = true;
      if(!isset($cm->includes[$file]))
      {
        foreach($m->includes as $f => $_)
          $cm->includes[$f] = 1;
        foreach($m->defs as $n => $d)
        {
          if(isset($cm->defs[$n]) && $cm->defs[$n] !== $d)
            throw new Exception("Def '$n' is already defined in '{$cm->file}' (check {$cm->defs[$n]->file})");
          $cm->defs[$n] = $d;
        }
      }
    }
    $cm->includes[$file] = 1;

    return $need_include_macro ? "<%INC($file)%>" : '';
  }

  private function _processIncludes($file, $txt)
  {
    if(strpos($txt, 'INC') !== false)
    {
      $self = $this;
      $txt = preg_replace_callback(
        '~<%\s*INC\s*\(\s*"([^"]+)"\s*\)\s*%>~', 
        function($m) use($self, $file) { return $self->_includesCallback($m, $file); }, 
        $txt);
    }
    
    return $txt;
  }

  function _isIncluded($file)
  {
    $file = jsm_normalize_path($file);
    return isset($this->includes[$file]);
  }

  function _hasExtension($file, $ext)
  {
    return strpos($file, $ext, strlen($file) - strlen($ext) - 1) !== false;
  }

  static function getDeps($base_dir, $file)
  {
    $deps = array();
    self::_getDeps($base_dir, $file, $deps);
    return $deps;
  }

  static private function _extractDeps($txt)
  {
    $dep_files = array();
    if(preg_match_all('~<%\s*((?:INC)|(?:BHL))\s*\(\s*"([^\n]+)~', $txt, $ms))
    {
      foreach($ms[1] as $idx => $type)
      {
        $raw_dep = $ms[2][$idx];

        $is_bhl = $type === "BHL";
        if($is_bhl)
        {
          $bhl_imps = explode(',', str_replace('"', '', $raw_dep));
          foreach($bhl_imps as $bhl_imp)
          {
            if($bhl_imp)
              $dep_files[$bhl_imp . '.bhl'] = true;
          }
        }
        else
        {
          $dep_file = substr($raw_dep, 0, strpos($raw_dep, '"'));
          $dep_files[$dep_file] = false;
        }
      }
    }
    return $dep_files;
  }

  static private function _getDeps($base_dir, $file, &$deps)
  {
    static $cache = array();

    $local_deps = array();
    if(!isset($cache[$file]))
    {
      if(!is_file($file))
        throw new Exception("Bad file '$file'");
      $txt = file_get_contents($file);
      if($txt === false)
        throw new Exception("Bad file '$file'");
      
      $extracted_deps = self::_extractDeps($txt);

      foreach($extracted_deps as $inc => $is_bhl)
      {
        $dir = ($inc[0] == '/') ? $base_dir : dirname($file);
        $dep_file = jsm_normalize_path($dir . "/" . $inc);
        $local_deps[] = array($is_bhl, $dep_file);
        $cache[$file] = $local_deps;
      }
    }
    else
      $local_deps = $cache[$file];

    foreach($local_deps as $local_dep)
    {
      list($is_bhl, $dep_file) = $local_dep;

      if(in_array($dep_file, $deps))
        continue;
      $deps[] = $dep_file;

      //NOTE: bhl deps are shallow
      if(!$is_bhl)
      {
        try
        {
          self::_getDeps($base_dir, $dep_file, $deps);
        }
        catch(Exception $e)
        {
          throw new Exception("Bad deps for '$file' : " . $e->getMessage());
        }
      }
    }  
  }

  private function _extractDefNameAndArgs($full_name)
  {
    $pos = strpos($full_name, '(');
    if($pos == -1)
      throw new Exception("Bad args string: $full_name");
    $name = substr($full_name, 0, $pos);

    $args_str = substr($full_name, $pos+1, strlen($full_name) - ($pos + 2));
    $args = $this->_parseMacroDefArgs($args_str);

    return array($name, $args);
  }

  private function _parseMacroDefArgs($args_str)
  {
    if(!$args_str)
      return array();
    return $this->args_parser->parseDef($args_str);
  }

  function nodes2str($nodes_or_str)
  {
    $str = '';
    if(is_array($nodes_or_str))
    {
      $this->_pushBuffer();
      foreach($nodes_or_str as $n)
        $n->call($this);
      $str = $this->_popBuffer();
    }
    else if(is_string($nodes_or_str))
      $str = $nodes_or_str;
    else
      throw new Exception("Bad value: $nodes_or_str");
    return $str;
  }

  function _processMacroArgs($arg_nodes_or_str)
  {
    $str = $this->nodes2str($arg_nodes_or_str);
    return $this->_parseMacroArgsStr($str);
  }

  function _parseMacroArgsStr($orig_args_str)
  {
    static $cache = array();

    if(!$orig_args_str)
      return array(false, array());

    //NOTE: this is potentially dangerous?
    $may_cache = strpos($orig_args_str, '<%') === false;
    if($may_cache && isset($cache[$orig_args_str]))
      return $cache[$orig_args_str];

    $args_str = $this->_removeBlockComments($orig_args_str);
    $args_str = $this->_removeLineComments($args_str);
    $args_str = rtrim($args_str, ',');

    $res = $this->args_parser->parseInvoke($args_str);

    if($may_cache)
      $cache[$orig_args_str] = $res;

    return $res;
  }

  private function _extractScriptDefs($file, $txt)
  {
    if(strpos($txt, 'def') === false)
      return $txt;

    //NOTE: make it more robust
    $lexer_rules = array(
      '~def\s+((\w+)\([^\)]*\))(.*?)\s*\n\bend\b~sA' => 1,
      '~[^\r\n]+~A'                                  => 2,
      '~\r\n?|\n~A'                                  => 3,
    );
    $tokens = jsm_lex($txt, $lexer_rules);
    
    $txt = '';
    foreach($tokens as $token)
    {
      if($token[0] == 1)
      {
        list($name, $args) = $this->_extractDefNameAndArgs($token[1][1]);
        $body = $token[1][3];

        $m = $this->_currentModule();
        if(isset($m->defs[$name]))
          throw new Exception("Def '$name' is already defined in '{$m->defs[$name]->file}' (check '$file')");

        if(JSM_MacroPHPNode::isValid($name))
          throw new Exception("Def '$name' conflicts with PHP macro");

        $node = new JSM_MacroDefNode($name, $args, $file);
        $m->defs[$name] = $node;

        $this->_parseDefBody($node, $file, $body);

        //var_dump($name, $body);
      }
      else
        $txt .= $token[1][0];
    }
    return $txt;
  }

  private function _replaceVarsWithMacro($file, $txt)
  {
    //simple vals
    $txt = preg_replace(
      '~\{(\$[a-zA-Z0-9_]+)\}~', 
      '<%SVAL($1)%>',
      $txt
    );
    //complex vals
    $txt = preg_replace(
      '~\{(\$[^\}]+)\}~', 
      '<%VAL($1)%>',
      $txt
    );
    return $txt;
  }

  private function _parseDefBody(JSM_MacroDefNode $node, $file, $txt)
  {
    $txt = $this->_replaceVarsWithMacro($file, $txt);

    if(strpos($txt, '<%') === false)
    {
      $node->addChild(new JSM_TextNode($txt));
      return;
    }

    $this->_pushNode($node);

    //the idea here is to split the whole text by macro start/end tags
    $lexer_rules = array(
      '~<%\s*(/?\w+)\s*\(~A'                => 1,
      '~\)\s*%>~A'                          => 2,
      '~[^\r\n]+?(?=(?:<%)|(?:\)\s*%>))~A'  => 3,
      '~[^\r\n]+~A'                         => 4,
      '~\r\n?|\n~A'                         => 5,
    );
    $tokens = jsm_lex($txt, $lexer_rules);

    foreach($tokens as $token)
    {
      if($token[0] == 1) //starting macro invokation
      {
        $name = $token[1][1];
        //for neat things like <%/IF()%> => <%ENDIF()%>
        if($name[0] === '/')
          $name = 'END'. substr($name, 1);

        $mcall = $this->_newCall($name);
        if($mcall === null)
          throw new Exception("No node for '$name'");

        $this->_pushNode($mcall);
      }
      else if($token[0] == 2) //finishing macro invocation
      {
        $mcall = $this->_popNode();
        if($mcall === null)
          throw new Exception("Non paired macro ending");
        $tmp_node = $this->_node(false/*non strict*/);
        if($tmp_node == null)
          throw new Exception("No current node(prev. node " . $mcall->name . ")");
        $tmp_node->addChild($mcall);
      }
      else
      {
        $txt = $token[1][0]; 
        $node = $this->_node();
        //text append optimization
        if($node instanceof JSM_MacroCallNode)
          $node->addText($txt);
        else
          $node->addChild(new JSM_TextNode($txt));
      }
    }

    $this->_popNode();
  }

  function _newCall($name)
  {
    $func = "macro_ex_{$name}";
    if(is_callable($func))
    {
      return $func($this);
    }
    else
    {
      return new JSM_MacroCallNode($name);
    }
  }

  function _getMacro($name)
  {
    if(isset($this->defs[$name]))
      return $this->defs[$name];

    if(JSM_MacroPHPNode::isValid($name))
    {
      $node = new JSM_MacroPHPNode($name);
      $this->defs[$name] = $node;
      return $node;
    }

    throw new Exception("Macro '$name' not found");
  }
}

class JSM_Module
{
  var $file = '';
  var $defs = array();
  var $includes = array();
  var $node = null;

  function __construct($file)
  {
    $this->file = $file;
  }
 
  function getIncludes()
  {
    return $this->includes;
  }

  function getFile()
  {
    return $this->file;
  }
}

interface JSM_MacroNode
{
  function call(JSM $jsm);
}

interface JSM_MacroInternalNode extends JSM_MacroNode
{
  function addChild(JSM_MacroNode $node);
}

class JSM_TextNode implements JSM_MacroNode
{
  var $txt;

  function __construct($txt)
  {
    $this->txt = $txt;
  } 

  function call(JSM $jsm)
  {
    $jsm->_buffer()->addContent($this->txt);
  }
}

class JSM_MacroCallNode implements JSM_MacroInternalNode
{
  var $name;
  var $arg_nodes = array();

  function __construct($name)
  {
    $this->name = $name;
  }

  //NOTE: children are arg nodes
  function addChild(JSM_MacroNode $node)
  {
    $this->arg_nodes[] = $node;
  }

  function addText($txt)
  {
    if($this->arg_nodes && $this->arg_nodes[sizeof($this->arg_nodes)-1] instanceof JSM_TextNode)
      $this->arg_nodes[sizeof($this->arg_nodes)-1]->txt .= $txt;
    else
      $this->arg_nodes[] = new JSM_TextNode($txt);
  }

  function call(JSM $jsm)
  {
    try
    {
      $m = $jsm->_getMacro($this->name);
      $m->setUserArgs($this->arg_nodes);
      $m->call($jsm);
    }
    catch(Exception $e)
    {
      throw new Exception("Error calling '{$this->name}': " . $e->getMessage());
    }
  }
}

class JSM_MacroPHPNode implements JSM_MacroNode
{
  var $func;

  var $refl;
  var $user_args = '';

  var $is_builtin;
  var $is_eval_args; //arguments will be evaluated and eval result will be passed
  var $is_raw_args;  //arguments result string will be passed, not evaluated
  var $is_node_args; //argument nodes will be passed as is
  var $is_no_args;

  function __construct($func)
  {
    $this->func = $func;

    $php_func = "macro_$func";

    $this->refl = new ReflectionFunction($php_func);
    $doc = $this->refl->getDocComment();

    $this->is_builtin = strpos($doc, '@builtin') !== false;
    $this->is_raw_args = strpos($doc, '@raw_args') !== false;
    $this->is_eval_args = strpos($doc, '@eval_args') !== false;
    $this->is_no_args = strpos($doc, '@no_args') !== false;
    $this->is_node_args = strpos($doc, '@node_args') !== false;
  }

  static function isValid($func)
  {
    $php_func = "macro_$func";
    return is_callable($php_func);
  }

  function setUserArgs($arg_nodes_or_str)
  {
    $this->user_args = $arg_nodes_or_str;
  }

  function call(JSM $jsm)
  {
    //NOTE: making sure file containing PHP macro was actually included by this file
    if(!$this->is_builtin && !$jsm->_isIncluded($this->refl->getFileName()))
      throw new Exception("Not found");

    $named = false;
    $args = array();
    if($this->is_no_args)
      {} //just do nothing
    else if($this->is_eval_args)
      $args[] = jsm_eval_string($jsm, $jsm->nodes2str($this->user_args));
    else if($this->is_raw_args)
      $args[] = $jsm->nodes2str($this->user_args);
    else if($this->is_node_args)
      $args[] = $this->user_args;
    else
      list($named, $args) = $jsm->_processMacroArgs($this->user_args);

    if($named)
    {
      $params = $this->refl->getParameters();
      if($params)
        array_shift($params);
      //first parameter is JSM instance
      $call_args = array($jsm);
      foreach($params as $param)
      {
        $name = '$'.$param->getName();

        if(!$param->isOptional())
        {
          if(!array_key_exists($name, $args))
            throw new Exception("Required argument '$name' missing");

          $call_args[] = $args[$name];
        }
        else
        {
          if(array_key_exists($name, $args))
            $call_args[] = $args[$name];
          else
            $call_args[] = $param->getDefaultValue();
        }
      }
      $res = $this->refl->invokeArgs($call_args);
    }
    else
    {
      //first parameter is JSM instance
      array_unshift($args, $jsm);
      $res = $this->refl->invokeArgs($args);
    }

    if($res !== null)
    {                   
      $res = $this->_processPHPMacroResult($res);
      $jsm->_buffer()->addContent($res);
    }
  }

  private function _processPHPMacroResult($res)
  {
    if(is_array($res))
      $res = jsm_json_encode($res);
    else if(!is_string($res))
      $res = "$res";
    return $res;
  }
}

class JSM_MacroDefNode implements JSM_MacroInternalNode
{
  var $name = '';
  var $file = '';
  var $decl_args = array();
  var $node_args = array();
  var $children = array();

  function __construct($name, $decl_args = array(), $file = '')
  {
    $this->name = $name;
    $this->file = $file;
    $this->decl_args = $decl_args;
  }

  function setUserArgs($node_args_or_str)
  {
    $this->node_args = $node_args_or_str;
  }

  function addChild(JSM_MacroNode $node)
  {
    $this->children[] = $node;
  }

  function call(JSM $jsm)
  {
    $args_str = $jsm->nodes2str($this->node_args);

    $jsm->_pushVarScope();

    $this->_prepareArgs($jsm, $args_str);

    foreach($this->children as $c)
      $c->call($jsm);

    $jsm->_popVarScope();
  }

  function _prepareArgs(JSM $jsm, $args_str)
  {
    list($named, $user_args) = $jsm->_parseMacroArgsStr($args_str);

    $args = $this->decl_args;

    //NOTE: overriding default args if any
    if($named)
    {
      foreach($user_args as $k => $v)
      {
        if(!array_key_exists($k, $args))
          throw new Exception("Macro '{$this->name}' doesn't use argument '$k'");
        $args[$k] = $v;
      }
    }
    else
    {
      $arg_keys = array_keys($args);

      foreach($user_args as $i => $v)
      {
        if(!isset($arg_keys[$i]))
        {
          //var_dump($user_args);
          throw new Exception("Macro '{$this->name}' has no argument at pos '".($i+1)."'");
        }
        $args[$arg_keys[$i]] = $v;
      }
    }

    foreach($args as $k => $v)
    {
      if($v === null)
        throw new Exception("Macro '{$this->name}' argument '$k' not passed");

      $jsm->setVar($k, $v);
    }
  }
}

class JSM_TextBuffer
{
  private $txt = '';

  function addContent($txt)
  {
    $this->txt .= $txt;
  }

  function getContent()
  {
    return $this->txt;
  }
}

class JSM_Eval
{
  static function evaluate(JSM $jsm, array $bytecode)
  {
    $stack = array();
    $result = array('value' => 0, 'logical_op' => false);

    if(!$bytecode)
      throw new Exception("No bytecode");

    foreach($bytecode as $bc)
    {
      if($bc['op'] === 'IDENTIFIER')
      {
        $stack[] = $jsm->getVar($bc['arg']);
      }
      else if($bc['op'] === 'FUNC')
      {
        $result['logical_op'] = self::computeFunc($bc['arg'], $stack);
      }
      else if($bc['op'] === 'NUMBER')
      {
        $stack[] = 1*$bc['arg'];
      }
      else if($bc['op'] === 'STRING')
      {
        $stack[] = $bc['arg'];
      }
      else
        throw new Exception("Unknow opcode " . $bc['op']);
    }

    if(sizeof($stack) != 1)
      throw new Exception("Missing values on stack");

    $result['value'] = $stack[0];

    return $result;
  }

  static private function computeFunc($func, &$stack)
  {
    //NOP
    if($func === "")
      return true;

    if($func === "+")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $stack[] = ($a + $b);
      return true;
    }
    else if($func === "-")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $stack[] = ($a - $b);
      return true;
    }
    else if($func === "*")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $stack[] = ($a * $b);
      return true;
    }
    else if($func === "/")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $stack[] = ($a / $b);
      return true;
    }
    else if($func === ">")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = $a > $b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "<")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = $a < $b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "==")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = $a == $b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "!=")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = $a != $b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "&&")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = (bool)$a && (bool)$b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "||")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = (bool)$a || (bool)$b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "!")
    {
      $a = array_pop($stack);
      $res = !((bool)$a);
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === ">=")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = $a >= $b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "<=")
    {
      $b = array_pop($stack); $a = array_pop($stack);
      $res = $a <= $b;
      $stack[] = (int)$res;
      return $res;
    }
    else if($func === "u-")
    {
      $a = array_pop($stack);
      $stack[] = -1 * $a;
      return true;
    }
    else if($func === "round")
    {
      $a = array_pop($stack);
      $stack[] = round($a);
      return true;
    }
    else
    {
      throw new Exception("Unknown func " . $func);
      return false;
    }
  }
}

class JSM_Expr
{
  const T_Number          = 1001;
  const T_Identifier      = 1002;
  const T_String          = 1003;
  const T_LParen          = 1009;
  const T_RParen          = 1010;
  const T_Func            = 1011;

  //token, precedence, arity
  private $funcs = array(
    ","    => array("", 1, 0),
    "&&"    => array("&&", 2, 2),
    "||"    => array("||", 2, 2),
    "="    => array("=", 10, 2),
    "+"    => array("+", 12, 2),
    "-"    => array("-", 12, 2),
    ">"    => array(">", 12, 2),
    "<"    => array("<", 12, 2),
    "=="    => array("==", 12, 2),
    "!="    => array("!=", 12, 2),
    ">="    => array(">=", 12, 2),
    "<="    => array("<=", 12, 2),
    "*"    => array("*", 13, 2),
    "/"    => array("/", 13, 2),
    "!"   => array("!", 14, 1),
    "u-"   => array("u-", 16, 1),
    "u+"   => array("", 16, 0),
    "round"   => array("round", 16, 1),
  );

  private $source;
  private $cursor;

  function process($expr)
  {
    $this->source = $expr;
    $this->cursor = 0;

    $tokens = $this->_tokenize();
    $rpl = $this->_rpl($tokens);

    $bytecode = array();
    foreach($rpl as $t)
    {
      if($t[0] == self::T_Number)
      {
        $bytecode[] = array('op' => 'NUMBER', 'arg' => $t[1]);
      }
      else if($t[0] == self::T_Identifier)
      {
        $bytecode[] = array('op' => 'IDENTIFIER', 'arg' => $t[1]);
      }
      else if($t[0] == self::T_String)
      {
        $bytecode[] = array('op' => 'STRING', 'arg' => $t[1]);
      }
      else if($t[0] == self::T_Func)
      {
        $bytecode[] = array('op' => 'FUNC', 'arg' => $t[1][0]);
      }
      else
        $this->_error("Bad token {$t[0]}");
    }
    return $bytecode;
  }

  private function _rpl(array $tokens)
  {
    $rpl = array();
    $num_rpl = 0;
    
    $function_stack = array();
    $num_function_stack = 0;

    $par_level = 0;
    foreach($tokens as $token) 
    {
      switch($token[0]) 
      {
        case self::T_Number:
        case self::T_Identifier:
        case self::T_String:
          $rpl[$num_rpl++] = $token;
          break;
        case self::T_LParen:
          ++$par_level;
          break;
        case self::T_RParen:
          --$par_level;
          break;
        case self::T_Func:
        {
          $f = array($token, $token[1][1], $par_level);

          while($num_function_stack>0 && $this->_isPrecedenceGreaterOrEqual($function_stack[$num_function_stack-1], $f))
            $rpl[$num_rpl++] = $function_stack[--$num_function_stack][0];

          $function_stack[$num_function_stack++] = $f;
          break;
        }
      }
    }

    if($par_level != 0)
      $this->_error("Non matching parenthesis");
    
    while($num_function_stack>0)
      $rpl[$num_rpl++] = $function_stack[--$num_function_stack][0];

    return $rpl;
  }

  private function _isPrecedenceGreaterOrEqual(array $a, array $b)
  {
    return $this->_cmpFunc($a, $b) >= 0;
  }

  private function _cmpFunc(array $a, array $b)
  {
    //checking paren level first
    if($a[2] != $b[2]) return $a[2] - $b[2];
    //checking precedence
    return $a[1] - $b[1];
  }

  private function _symbol()
  {
    return substr($this->source, $this->cursor, 1);
  }

  private function _error($msg)
  {
    throw new Exception("Error in '$this->source': $msg");
  }

  private function _tokenize()
  {
    $tokens = array();
    // Determines if the next + or - is a binary or unary operator.
    $binary = false;

    while(true)
    {
      $token = null;

      $c = $this->_symbol();
      if($c === false || $c === '')
        break;

      ++$this->cursor;

      //identifiers
      if($c === '$')
      {
        //collect all chars of an identifier
        $start = $this->cursor;
        while(ctype_alnum($this->_symbol()) || $this->_symbol() == '_')
          $this->cursor++;
        $attribute = substr($this->source, $start, $this->cursor - $start);

        $token = array(self::T_Identifier, '$'.$attribute);

        $binary = true;
      }
      else if($c === '"')
      {
        //collect all chars of a string
        $start = $this->cursor;
        while($this->_symbol() !== '"')
          $this->cursor++;
        $attribute = substr($this->source, $start, $this->cursor - $start);

        $token = array(self::T_String, $attribute);
        $this->cursor++;
        $binary = true;
      }
      //functions
      else if(ctype_alpha($c))
      {
        //collect all chars of an identifier
        $start = $this->cursor - 1;
        while(ctype_alnum($this->_symbol()) || $this->_symbol() == '_')
          $this->cursor++;
        $attribute = substr($this->source, $start, $this->cursor - $start);

        if($this->_symbol() !== '(')
          $this->_error('( expected');

        $token = $this->_getFuncToken($attribute);

        $binary = true;
      }
      //numbers
      else if(ctype_digit($c))
      {
        $start = $this->cursor - 1;
        while(ctype_digit($this->_symbol())) $this->cursor++;
        if($this->_symbol() == '.')
        {
          $this->cursor++;
          while(ctype_digit($this->_symbol())) $this->cursor++;
        }

        $attribute = substr($this->source, $start, $this->cursor - $start);
        $token = array(self::T_Number, $attribute);

        $binary = true;
      }
      //operators
      else
      {
        switch($c)
        {
          case ' ': case "\r": case "\t": case "\n" : break;
          case '(': $token = array(self::T_LParen, $c); $binary = false; break;
          case ')': $token = array(self::T_RParen, $c); $binary = true; break;
          case '+': $token = $this->_getFuncToken(($binary ? '+' : 'u+'), $c); $binary = false; break;
          case '-': $token = $this->_getFuncToken(($binary ? '-' : 'u-'), $c); $binary = false; break;

          default:
            //try to peek the next symbol and check if such an operator exists
            $sym = $this->_symbol();
            if($sym !== false && $sym !== '' && ($token = $this->_findFuncToken($c . $sym)))
              $this->cursor++;
            else
              $token = $this->_getFuncToken($c);

            $binary = false;
        }
      }

      if($token !== null)
        $tokens[] = $token;
    }

    return $tokens;
  }

  private function _findFuncToken($c)
  {
    if(!isset($this->funcs[$c]))
      return null;

    $f = $this->funcs[$c];
    return array(self::T_Func, $f);
  }

  private function _getFuncToken($c)
  {
    $t = $this->_findFuncToken($c);
    if(!$t)
      $this->_error("can't find func token '$c'");
    return $t;
  }
}

function jsm_json_encode($data)
{
  //fixig weird PHP json_encode behavior
  $fixed = json_encode($data); 
  $fixed = str_replace(array('\\\\', '\\n', '\/'), array('\\', "\n", '/'), $fixed);
  return $fixed;
}

function jsm_lex($string, array $tokenMap) 
{
  $tokens = array();
  $offset = 0; // current offset in string
  while(isset($string[$offset]))   // loop as long as we aren't at the end of the string
  {
    foreach($tokenMap as $regex => $token) 
    {
      if(preg_match($regex, $string, $matches, null, $offset)) 
      {
        $tokens[] = array(
          $token,      // token ID      (e.g. T_FIELD_SEPARATOR)
          $matches
        );
        $offset += strlen($matches[0]);
        continue 2; // continue the outer while loop
      }
    }

    throw new Exception(sprintf('Unexpected character "%s"', $string[$offset]));
  }

  return $tokens;
}

function jsm_is_win()
{
  return !(DIRECTORY_SEPARATOR == '/');
}

function jsm_normalize_path($path, $unix=null/*null means try to guess*/)
{
  if(is_null($unix)) 
    $unix = !jsm_is_win();

  $path = str_replace('\\', '/', $path);
  $path = preg_replace('/\/+/', '/', $path);
  $parts = explode('/', $path);
  $absolutes = array();
  foreach($parts as $part) 
  {
    if('.' == $part) 
      continue;

    if('..' == $part) 
      array_pop($absolutes);
    else
      $absolutes[] = $part;
  }
  $res = implode($unix ? '/' : '\\', $absolutes);
  return $res;
}

function jsm_eval_string(JSM $jsm, $expr_str)
{
  $expr = new JSM_Expr();
  $bytecode = $expr->process($expr_str);
  return JSM_Eval::evaluate($jsm, $bytecode);
}

function jsm_eval_string_bool(JSM $jsm, $expr_str)
{
  $eval_res = jsm_eval_string($jsm, $expr_str);
  return $eval_res['logical_op'];
}

function jsm_eval_string_value(JSM $jsm, $expr_str)
{
  $eval_res = jsm_eval_string($jsm, $expr_str);
  return $eval_res['value'];
}

class JSM_ArgsParser
{
  const ERR_CONTEXT_CHARS = 200;

  private $in;
  private $len;
  private $c = 0;

  static $ORD_SPACE;
  static $ORD_0;
  static $ORD_9;

  function __construct()
  {
    self::$ORD_SPACE = ord(' ');
    self::$ORD_0 = ord('0');
    self::$ORD_9 = ord('9');
  }

  function reset($input)
  {
    $this->in = $input;
    $this->c = 0;
    $this->len = strlen($this->in);
  }

  function parseInvoke($input)
  {
    $this->reset($input);

    $args = array();
    $this->skip_whitespace();

    $named = false;
    if($this->curr() === '$')
    {
      $named = true;
      $this->parse_named_arg($args);
    }
    else
      $this->parse_arg($args);

    if($this->c != $this->len)
      $this->_error("Trailing content({$this->c} vs {$this->len})");

    return array($named, $args);
  }

  function parseDef($input)
  {
    $this->reset($input);

    $args = array();
    $this->parse_def_arg($args);
    return $args;
  }

  private function next()
  {
    if($this->c >= $this->len) 
      return false;
    return $this->in[$this->c++];
  }

  private function peek($n)
  {
    if(($this->c+$n) >= $this->len) 
      return false;
    return $this->in[$this->c+$n];
  }

  private function curr()
  {
    if($this->c >= $this->len) 
      return false;
    return $this->in[$this->c];
  }

  private function parse_def_arg(&$out)
  {
    $this->skip_whitespace();
    $name = $this->parse_arg_name();
    $this->skip_whitespace();

    $ch = $this->next();

    if($ch !== '=')
    {
      $out[$name] = null;
    }
    else
    {
      $this->skip_whitespace();
      $value = $this->parse_arg_value();
      $out[$name] = $value;
      $this->skip_whitespace();
      $ch = $this->next();
    }

    if($ch === ',')
      $this->parse_def_arg($out);
  }

  private function parse_named_arg(&$out)
  {
    $this->skip_whitespace();
    $name = $this->parse_arg_name();
    $this->skip_whitespace();

    if($this->next() !== '=')
      $this->_error("'=' expected");

    $this->skip_whitespace();

    $value = $this->parse_arg_value();

    $out[$name] = $value;

    $this->skip_whitespace();
    $ch = $this->next();
    if($ch === ',')
      $this->parse_named_arg($out);
  }

  private function parse_arg(&$out)
  {
    $this->skip_whitespace();

    $value = $this->parse_arg_value();
    $out[] = $value;

    $this->skip_whitespace();
    $ch = $this->next();
    if($ch === ',')
      $this->parse_arg($out);
  }

  private function parse_arg_name()
  {
    if($this->next() !== '$')
      $this->_error("'$' expected");

    $name = '$';
    while($this->c < $this->len && (ctype_alnum($ch = $this->in[$this->c]) || ($ch === '_')))
    {
      $name .= $ch;
      ++$this->c;
    }
    return $name;
  }

  private function parse_arg_value()
  {
    $ch = $this->curr();
    if($ch === false)
      $this->_error("No data for value");

    switch($ch)
    {
      case '[': return $this->parse_bracket_string();
      case '"': return $this->parse_string();
      case '\'': return $this->parse_multi_string();
      case '-': return $this->parse_number();
      default: 
        if(ord($ch) >= self::$ORD_0 && ord($ch) <= self::$ORD_9) 
          return $this->parse_number();
        else
          $this->_error("Not expected symbol");
    }
  }

  private function parse_bracket_string()
  {
    if($this->curr() !== '[')
      $this->_error("'[' expected");

    $brackets = 1;

    $start = $this->c;
    ++$this->c;

    while($this->c < $this->len)
    {
      $ch =$this->in[$this->c]; 
      if($ch === ']')
        --$brackets;
      else if($ch === '[')
        ++$brackets;

      if($brackets == 0)
      {
        ++$this->c;
        $end = $this->c;
        return substr($this->in, $start, $end - $start);
      }
      ++$this->c;
    }

    $this->_error("Non matching '['");
  }

  private function parse_string()
  {
    if($this->next() !== '"')
      $this->_error("'\"' expected");

    $start = $this->c;

    while($this->c < $this->len)
    {
      if($this->in[$this->c] === '"')
      {
        $end = $this->c;
        ++$this->c;
        return substr($this->in, $start, $end - $start);
      }
      ++$this->c;
    }

    $this->_error("Bad string");
  }

  private function parse_multi_string()
  {
    if($this->next() !== '\'')
      $this->_error("' expected");
    if($this->next() !== '\'')
      $this->_error("' expected");
    if($this->next() !== '\'')
      $this->_error("' expected");

    $start = $this->c;

    while($this->c < $this->len)
    {
      if($this->peek(1) === "'" && $this->peek(2) === "'" && $this->peek(3) === "'")
      {
        $end = $this->c;
        $this->c += 4;
        return substr($this->in, $start, $end - $start + 1);
      }
      ++$this->c;
    }

    $this->_error("Bad multi string");
  }

  private function parse_number()
  {
    $is_float = false;
    $start = $this->c;

    if($this->in[$this->c] == '-')
      ++$this->c;

    while($this->c < $this->len && ord($this->in[$this->c]) >= self::$ORD_0 && ord($this->in[$this->c]) <= self::$ORD_9)
      ++$this->c;

    if($this->c < $this->len && $this->in[$this->c] == '.')
    {
      $is_float = true;
      ++$this->c;

      while($this->c < $this->len && ord($this->in[$this->c]) >= self::$ORD_0 && ord($this->in[$this->c]) <= self::$ORD_9)
        ++$this->c;
    }

    if($this->c < $this->len && ($this->in[$this->c] == 'e' || $this->in[$this->c] == 'E'))
    {
      $is_float = true;
      ++$this->c;

      if($this->c < $this->len && ($this->in[$this->c] == '-' || $this->in[$this->c] == '+'))
        ++$this->c;

      while($this->c < $this->len && ord($this->in[$this->c]) >= self::$ORD_0 && ord($this->in[$this->c]) <= self::$ORD_9)
        ++$this->c;
    }

    if($is_float)
      return 1*substr($this->in, $start, $this->c - $start);
    else
      return (int)(1*substr($this->in, $start, $this->c - $start));
  }

  private function _error($error)
  {
    if($this->c < $this->len)
      throw new Exception("Parse error: $error\n" . $this->show_position($this->c));
    else
      throw new Exception("Parse error: $error\n" . $this->show_position($this->len-1));
  }

  private function skip_whitespace()
  {
    while($this->c < $this->len && ord($this->in[$this->c]) <= self::$ORD_SPACE)
      ++$this->c;
  }

  private function show_position($p)
  {
    $pre = str_replace("\n", '', $this->get_past_input($p));
    $c = str_repeat('-', max(0, strlen($pre) - 1));

    return $pre . str_replace("\n", '', $this->get_upcoming_input($p)) . "\n" . $c . "^";
  }

  private function get_past_input($c)
  {
    $past = substr($this->in, 0, $c+1);
    return (strlen($past) > self::ERR_CONTEXT_CHARS ? '...' : '') . substr($past, -self::ERR_CONTEXT_CHARS);
  }

  private function get_upcoming_input($c)
  {
    $next = substr($this->in, $c+1);
    return substr($next, 0, self::ERR_CONTEXT_CHARS) . (strlen($next) > self::ERR_CONTEXT_CHARS ? '...' : '');
  }
}

//////////////////////////////////////////////////////

/**
 * @builtin @raw_args
 */
function macro_DEP($jsm)
{}

/**
 * @builtin @raw_args
 */
function macro_INC($jsm, $file)
{
  $m = $jsm->getModule($file);
  $m->node->call($jsm);
}

/**
 * @builtin @raw_args
 */
function macro_LET($jsm, $txt_args)
{
  $items = explode("=", $txt_args, 2);
  $eval_res = jsm_eval_string($jsm, $items[1]);
  $jsm->setVar(trim($items[0]), $eval_res['value']);
}

/**
 * @builtin @raw_args
 */
function macro_VAL($jsm, $txt_args)
{
  if(strpos($txt_args, '$$') === 0)
  {
    $const_name = $txt_args;
    if(!preg_match('~^\$\$[a-zA-Z0-9_]+$~', $const_name))
      throw new Exception("Bad characters in const name: '{$const_name}'");
    return $jsm->getAutoConst(substr($const_name, 2));
  }

  if(strpos($txt_args, '$(') === 0)
    $txt_args = ltrim($txt_args, '$');

  $eval_res = jsm_eval_string($jsm, $txt_args);
  return $eval_res['value'];
}

//simple version of variable echoing
/**
 * @builtin @raw_args
 */
function macro_SVAL($jsm, $txt_args)
{
  return $jsm->getVar($txt_args);
}

/**
 * @builtin
 */
function macro_CONST($jsm, $k, $v)
{
  $jsm->setConst($k, $v);
}

class JSM_If implements JSM_MacroInternalNode
{
  private $branches = array();

  function addToArgs(JSM_MacroNode $node)
  {
    if($this->branches && $this->branches[sizeof($this->branches)-1]['cond'] === null)
      throw new Exception("ELSE has no args");

    $this->branches[sizeof($this->branches)-1]['cond'][] = $node;
  }

  function addChild(JSM_MacroNode $node)
  {
    $b = &$this->branches[sizeof($this->branches)-1]['nodes'];
    $b[] = $node;
  }

  function addBranch()
  {
    if($this->branches && $this->branches[sizeof($this->branches)-1]['cond'] === null)
      throw new Exception("Not expecting any more branches");

    $this->branches[] = array('cond' => array(), 'nodes' => array());

    return new JSM_IfBranch($this);
  }

  function addElse()
  {
    $this->branches[] = array('cond' => null, 'nodes' => array());

    return new JSM_IfBranch($this);
  }

  function call(JSM $jsm)
  {
    $branch_found = false;

    foreach($this->branches as $b)
    {
      //else special case
      if($b['cond'] === null)
        continue;

      $cond_txt = $jsm->nodes2str($b['cond']); 

      if(jsm_eval_string_bool($jsm, $cond_txt))
      {
        foreach($b['nodes'] as $node)
        {
          $node->call($jsm);
        }
        $branch_found = true;
      }
    }

    if(!$branch_found)
    {
      $b = $this->branches[sizeof($this->branches)-1];
      //checking if it's an else node
      if($b['cond'] === null)
      {
        foreach($b['nodes'] as $node)
          $node->call($jsm);
      }
    }
  }
}

class JSM_IfBranch implements JSM_MacroInternalNode
{
  private $if;

  function __construct(JSM_If $if)
  {
    $this->if = $if;
  }

  function addChild(JSM_MacroNode $node)
  {
    $this->if->addToArgs($node);
  }

  function call(JSM $jsm)
  {}
}

function macro_ex_IF(JSM $jsm)
{
  $if = new JSM_If();
  $jsm->_pushNode($if);
  return $if->addBranch();
}

function macro_ex_ELSIF(JSM $jsm)
{
  $if = $jsm->_node();
  if(!($if instanceof JSM_If))
    throw new Exception("Not expected ELSIF");
  return $if->addBranch();
}

function macro_ex_ELSE(JSM $jsm)
{
  $if = $jsm->_node();
  if(!($if instanceof JSM_If))
    throw new Exception("Not expected ELSE");
  return $if->addElse();
}

function macro_ex_ENDIF(JSM $jsm)
{
  $if = $jsm->_popNode();
  if(!($if instanceof JSM_If))
    throw new Exception("Not expected ENDIF");
  return $if;
}

class JSM_Rep implements JSM_MacroInternalNode
{
  private $children = array();
  private $rep_args = array();

  function addNumber()
  {
    return new JSM_RepNumber($this);
  }

  function addToArgs(JSM_MacroNode $node)
  {
    $this->rep_args[] = $node;
  }

  function addChild(JSM_MacroNode $n)
  {
    $this->children[] = $n;
  }

  function call(JSM $jsm)
  {
    $reps = jsm_eval_string_value($jsm, $jsm->nodes2str($this->rep_args));

    for($i=0;$i<$reps;++$i)
    {
      $jsm->setVar('$_REP_INDEX_', $i);
      foreach($this->children as $n)
        $n->call($jsm);
    }
  }
}

class JSM_RepNumber implements JSM_MacroInternalNode
{
  var $rep;

  function __construct(JSM_Rep $rep)
  {
    $this->rep = $rep;
  }

  function addChild(JSM_MacroNode $n)
  {
    $this->rep->addToArgs($n);
  }

  function call(JSM $jsm)
  {}
}

function macro_ex_REP(JSM $jsm)
{
  $rep = new JSM_Rep();
  $jsm->_pushNode($rep);
  return $rep->addNumber();
}

function macro_ex_ENDREP(JSM $jsm)
{
  $rep = $jsm->_popNode();
  if(!($rep instanceof JSM_Rep))
    throw new Exception("Not expected ENDREP");
  return $rep;
}

/**
 * @builtin @raw_args
 */
function macro_CALL($proc, $raw_args)
{
  list($name, $call_args) = explode(",", $raw_args, 2);
  $name = trim($name, '"');
  $m = $proc->_getMacro($name);
  $m->setUserArgs($call_args);
  $m->call($proc);
}

/**
 * @builtin @eval_args
 */
function macro_TRACE($jsm, array $eval_res)
{
  echo "TRACE: " . $eval_res['value'] . "\n";
}

/**
 * @builtin @raw_args
 */
function macro_LET_IF($jsm, $raw_args)
{
  list($let, $cond) = explode(",", $raw_args, 2);

  $eval_res = jsm_eval_string($jsm, $cond);

  if($eval_res['logical_op'])
  {
    $items = explode("=", $let, 2);
    $eval_res = jsm_eval_string($jsm, $items[1]);
    $jsm->setVar(trim($items[0]), $eval_res['value']);
  }
}