harbour-core/harbour/source/rtl/do.c

/*
 * $Id$
 */

/*
 * Harbour Project source code:
 * DO(), EVAL() functions and DO command
 *
 * Copyright 1999 Ryszard Glab <rglab@imid.med.pl>
 * www - http://www.harbour-project.org
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version, with one exception:
 *
 * The exception is that if you link the Harbour Runtime Library (HRL)
 * and/or the Harbour Virtual Machine (HVM) with other files to produce
 * an executable, this does not by itself cause the resulting executable
 * to be covered by the GNU General Public License. Your use of that
 * executable is in no way restricted on account of linking the HRL
 * and/or HVM code into it.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA (or visit
 * their web site at http://www.gnu.org/).
 *
 */

#include "extend.h"
#include "itemapi.h"
#include "errorapi.h"
#include "ctoharb.h"

/*  $DOC$
 *  $FUNCNAME$
 *    DO()
 *  $CATEGORY$
 *    Utility
 *  $ONELINER$
 *    Calls a procedure or a function
 *  $SYNTAX$
 *    DO( <xFuncProc> [, <xArguments...>] )
 *  $ARGUMENTS$
 *    <xFuncProc> = Either a string with a function/procedure name to be called
 *          or a codeblock to evaluate
 *    <xArguments> = arguments passed to a called function/procedure or to
 *          a codeblock
 *  $RETURNS$
 *    A value that was returned from called function
 *  $DESCRIPTION$
 *    This function can be called either by the harbour compiler or by user.
 *    The compiler always passes the item of IT_SYMBOL type that stores the
 *    name of procedure specified in DO <proc> WITH ... statement.
 *       If called procedure/function doesn't exist then the runtime error
 *    is generated.
 *       This function can be used as replacement of macro operator.
 *    It is also used internally to implement DO <proc> WITH <args...>
 *    In this case <xFuncProc> is of type HB_SYMB
 *  $EXAMPLES$
 *       cbCode ={|x| MyFunc( x )}
 *       DO( cbCode, 1 )
 *
 *       cFunction := "MyFunc"
 *       xRetVal :=DO( cFunction, 2 )
 *
 *       Old style (slower):
 *          DO &cFunction WITH 3
 *
 *  $TESTS$
 *
 *  $STATUS$
 *
 *  $COMPLIANCE$
 *
 *  $SEEALSO$
 *
 *  $END$
 */
HARBOUR HB_DO( void )
{
   USHORT uiPCount = hb_pcount();
   PHB_ITEM pItem = hb_param( 1, IT_ANY );

   if( IS_STRING( pItem ) )
   {
      PHB_DYNS pDynSym = hb_dynsymFindName( hb_itemGetCPtr( pItem ) );

      if( pDynSym )
      {
         USHORT uiParam;

         hb_vmPushSymbol( pDynSym->pSymbol );
         hb_vmPushNil();
         for( uiParam = 2; uiParam <= uiPCount; uiParam++ )
            hb_vmPush( hb_param( uiParam, IT_ANY ) );
         hb_vmDo( uiPCount - 1 );
      }
      else
         hb_errRT_BASE( EG_NOFUNC, 1001, NULL, pItem->item.asString.value );
   }
   else if( IS_BLOCK( pItem ) )
   {
      USHORT uiParam;

      hb_vmPushSymbol( &hb_symEval );
      hb_vmPush( pItem );
      for( uiParam = 2; uiParam <= uiPCount; uiParam++ )
         hb_vmPush( hb_param( uiParam, IT_ANY ) );
      hb_vmDo( uiPCount - 1 );
   }
   else if( IS_SYMBOL( pItem ) )
   {
      USHORT uiParam;

      hb_vmPushSymbol( pItem->item.asSymbol.value );
      hb_vmPushNil();
      for( uiParam = 2; uiParam <= uiPCount; uiParam++ )
         hb_vmPush( hb_param( uiParam, IT_ANY ) );
      hb_vmDo( uiPCount - 1 );
   }
   else
   {
      PHB_ITEM pResult = hb_errRT_BASE_Subst( EG_ARG, 3012, NULL, "DO" );

      if( pResult )
      {
         hb_itemReturn( pResult );
         hb_itemRelease( pResult );
      }
   }
}

HARBOUR HB_EVAL( void )
{
   USHORT uiPCount = hb_pcount();
   PHB_ITEM pItem = hb_param( 1, IT_BLOCK );

   if( pItem )
   {
      USHORT uiParam;

      hb_vmPushSymbol( &hb_symEval );
      hb_vmPush( pItem );
      for( uiParam = 2; uiParam <= uiPCount; uiParam++ )
         hb_vmPush( hb_param( uiParam, IT_ANY ) );
      hb_vmDo( uiPCount - 1 );
   }
   else
   {
      PHB_ITEM pResult = hb_errRT_BASE_Subst( EG_NOMETHOD, 1004, NULL, "EVAL" );

      if( pResult )
      {
         hb_itemReturn( pResult );
         hb_itemRelease( pResult );
      }
   }
}