<?php

/*

homepage: http://arc.semsol.org/

license:  http://arc.semsol.org/license



class:    ARC2 SPARQLScript Parser (SPARQL+ + functions)

author:   Benjamin Nowack

version:  2008-08-04 (Fix: last query block was not correctly extracted 

                      Addition: varMerge) 

*/



ARC2::inc('ARC2_SPARQLPlusParser');



class ARC2_SPARQLScriptParser extends ARC2_SPARQLPlusParser {



  function __construct($a = '', &$caller) {

    parent::__construct($a, $caller);

  }

  

  function ARC2_SPARQLScriptParser($a = '', &$caller) {

    $this->__construct($a, $caller);

  }



  function __init() {

    parent::__init();

  }



  /*  */



  function parse($v, $src = '') {

    $this->setDefaultPrefixes();

    $this->base = $src ? $this->calcBase($src) : ARC2::getScriptURI();

    $this->blocks = array();

    $this->r = array('base' => '', 'vars' => array(), 'prefixes' => $this->prefixes);

    do {

      $proceed = 0;

      if ((list($r, $v) = $this->xScriptBlock($v)) && $r) {

        $this->blocks[] = $r;

        $proceed = 1;

      }

      $this->unparsed_code = trim($v);

    } while ($proceed);

    if (trim($this->unparsed_code) && !$this->getErrors()) {

      $rest = preg_replace('/[\x0a|\x0d]/i', ' ', substr($this->unparsed_code, 0, 30));

      $msg = trim($rest) ? 'Could not properly handle "' . $rest . '"' : 'Syntax Error';

      $this->addError($msg);

    }

  }

  

  function getScriptBlocks() {

    return $this->v('blocks', array());

  }



  /*  */



  function xScriptBlock($v) {

    /* comment removal */  

    while (preg_match('/^\s*(\#[^\xd\xa]*)(.*)$/si', $v, $m)) $v = $m[2];

    /* BaseDecl */

    if ((list($sub_r, $v) = $this->xBaseDecl($v)) && $sub_r) {

      $this->base = $sub_r;

    }

    /* PrefixDecl */

    while ((list($r, $v) = $this->xPrefixDecl($v)) && $r) {

      $this->prefixes[$r['prefix']] = $r['uri'];

    }

    /* EndpointDecl */

    if ((list($r, $v) = $this->xEndpointDecl($v)) && $r) {

      return array($r, $v);

    }

    /* Assignment */

    if ((list($r, $v) = $this->xAssignment($v)) && $r) {

      return array($r, $v);

    }

    /* IFBlock */

    if ((list($r, $v) = $this->xIFBlock($v)) && $r) {

      return array($r, $v);

    }

    /* FORBlock */

    if ((list($r, $v) = $this->xFORBlock($v)) && $r) {

      return array($r, $v);

    }

    /* String */

    if ((list($r, $v) = $this->xString($v)) && $r) {

      return array($r, $v);

    }

    /* Query */

    $prev_r = $this->r;

    $this->r = array('base' => '', 'vars' => array(), 'prefixes' => $this->prefixes);

    if ((list($r, $rest) = $this->xQuery($v)) && $r) {

      $q = $rest ? trim(substr($v, 0, -strlen($rest))) : trim($v);

      $v = $rest;

      $r = array_merge($this->r, array(

        'type' => 'query',

        'query_type' => $r['type'],

        'query' => $q,

        //'prefixes' => $this->prefixes,

        'base' => $this->base,

        //'infos' => $r

      ));

      return array($r, $v);

    }

    else {

      $this->r = $prev_r;

    }

    return array(0, $v);

  }



  function xBlockSet($v) {

    if (!$r = $this->x("\{", $v)) return array(0, $v);

    $blocks = array();

    $sub_v = $r[1];

    while ((list($sub_r, $sub_v) = $this->xScriptBlock($sub_v)) && $sub_r) {

      $blocks[] = $sub_r;

    }

    if (!$sub_r = $this->x("\}", $sub_v)) return array(0, $v);

    $sub_v = $sub_r[1];

    return array(array('type' => 'block_set', 'blocks' => $blocks), $sub_v);

  }

  

  /* s2 */

  

  function xEndpointDecl($v) {

    if ($r = $this->x("ENDPOINT\s+", $v)) {

      if ((list($r, $sub_v) = $this->xIRI_REF($r[1])) && $r) {

        $r = $this->calcUri($r, $this->base);

        if ($sub_r = $this->x('\.', $sub_v)) {

          $sub_v = $sub_r[1];

        }

        return array(

          array('type' => 'endpoint_decl', 'endpoint' => $r),

          $sub_v

        );

      }

    }

    return array(0, $v);

  }

  

  /* s3 */

  

  function xAssignment($v) {

    /* Var */

    list($r, $sub_v) = $this->xVar($v);

    if (!$r) return array(0, $v);

    $var = $r;

    /* := | = */

    if (!$sub_r = $this->x("\:?\=", $sub_v)) return array(0, $v);

    $sub_v = $sub_r[1];

    /* try String */

    list($r, $sub_v) = $this->xString($sub_v);

    if ($r) return array(array('type' => 'assignment', 'var' => $var, 'sub_type' => 'string', 'string' => $r), ltrim($sub_v, '; '));

    /* try VarMerge */

    list($r, $sub_v) = $this->xVarMerge($sub_v);

    if ($r) return array(array('type' => 'assignment', 'var' => $var, 'sub_type' => 'var_merge', 'var2' => $r[0], 'var3' => $r[1]), ltrim($sub_v, '; '));

    /* try Var */

    list($r, $sub_v) = $this->xVar($sub_v);

    if ($r) return array(array('type' => 'assignment', 'var' => $var, 'sub_type' => 'var', 'var2' => $r), ltrim($sub_v, '; '));

    /* try Placeholder */

    list($r, $sub_v) = $this->xPlaceholder($sub_v);

    if ($r) return array(array('type' => 'assignment', 'var' => $var, 'sub_type' => 'placeholder', 'placeholder' => $r), ltrim($sub_v, '; '));

    /* try query */

    $prev_r = $this->r;

    $this->r = array('base' => '', 'vars' => array(), 'prefixes' => $this->prefixes);

    list($r, $rest) = $this->xQuery($sub_v);

    if (!$r) {

      $this->r = $prev_r;

      return array(0, $v);

    }

    else {

      $q = trim(str_replace(trim($rest), '', $sub_v));

      return array(

        array(

          'type' => 'assignment', 

          'var' => $var,

          'sub_type' => 'query',

          'query' => array_merge($this->r, array(

            'type' => 'query',

            'query_type' => $r['type'],

            'query' => $q,

            'base' => $this->base,

          )),

        ),

        ltrim($rest, '; ')

      );

    }

  }

  

  /* s4 'IF' BrackettedExpression '{' Script '}' ( 'ELSE' '{' Script '}')?  */

  

  function xIFBlock($v) {

    if ($r = $this->x("IF\s*", $v)) {

      if ((list($sub_r, $sub_v) = $this->xBrackettedExpression($r[1])) && $sub_r) {

        $cond = $sub_r;

        if ((list($sub_r, $sub_v) = $this->xBlockSet($sub_v)) && $sub_r) {

          $blocks = $sub_r['blocks'];

          /* else */

          $else_blocks = array();

          $rest = $sub_v;

          if ($sub_r = $this->x("ELSE\s*", $sub_v)) {

            if ((list($sub_r, $sub_v) = $this->xBlockSet($sub_r[1])) && $sub_r) {

              $else_blocks = $sub_r['blocks'];

            }

            else {

              $sub_v = $rest;

            }

          }

          return array(

            array(

              'type' => 'ifblock',

              'condition' => $cond,

              'blocks' => $blocks,

              'else_blocks' => $else_blocks,

            ),

            $sub_v

          );

        }

      }

    }

    return array(0, $v);

  }

  

  /* s5 'FOR' '(' Var 'IN' Var ')' '{' Script '}' */

  

  function xFORBlock($v) {

    if ($r = $this->x("FOR\s*\(\s*[\$\?]([^\s]+)\s+IN\s+[\$\?]([^\s]+)\s*\)", $v)) {/* @@todo split into sub-patterns? */

      $iterator = $r[1];

      $set_var = $r[2];

      $sub_v = $r[3];

      if ((list($sub_r, $sub_v) = $this->xBlockSet($sub_v)) && $sub_r) {

        return array(

          array(

            'type' => 'forblock',

            'set' => $set_var,

            'iterator' => $iterator,

            'blocks' => $sub_r['blocks']

          ),

          $sub_v

        );

      }

    }

    return array(0, $v);

  }

  

  /* s6 Var '+' Var */

  

  function xVarMerge($v) {

    if ((list($sub_r, $sub_v) = $this->xVar($v)) && $sub_r) {

      $var1 = $sub_r;

      if ($sub_r = $this->x("\+", $sub_v)) {

        $sub_v = $sub_r[1];

        if ((list($sub_r, $sub_v) = $this->xVar($sub_v)) && $sub_r) {

          return array(

            array($var1, $sub_r),

            $sub_v

          );

        }

      }

    }

    return array(0, $v);

  }

  

}