/*
* IncrCmd.java
*
* Copyright (c) 1997 Cornell University.
* Copyright (c) 1997-1998 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
* 
* Included in SQLite3 port to C# for use in testharness only;  2008 Noah B Hart
*
* RCS @(#) $Id: IncrCmd.java,v 1.2 1999/08/03 02:56:23 mo Exp $
*
*/
using System;
namespace tcl.lang
{

  /// <summary> This class implements the built-in "incr" command in Tcl.</summary>
  class IncrCmd : Command
  {
    /// <summary> This procedure is invoked to process the "incr" Tcl command.
    /// See the user documentation for details on what it does.
    /// </summary>
    /// <exception cref=""> TclException if wrong # of args or increment is not an
    /// integer.
    /// </exception>

    public TCL.CompletionCode cmdProc( Interp interp, TclObject[] objv )
    {
      int incrAmount;
      TclObject newValue;

      if ( ( objv.Length != 2 ) && ( objv.Length != 3 ) )
      {
        throw new TclNumArgsException( interp, 1, objv, "varName ?increment?" );
      }

      // Calculate the amount to increment by.

      if ( objv.Length == 2 )
      {
        incrAmount = 1;
      }
      else
      {
        try
        {
          incrAmount = TclInteger.get( interp, objv[2] );
        }
        catch ( TclException e )
        {
          interp.addErrorInfo( "\n    (reading increment)" );
          throw;
        }
      }

      // Increment the variable's value.

      newValue = Var.incrVar( interp, objv[1], null, incrAmount, TCL.VarFlag.LEAVE_ERR_MSG );

      // FIXME: we need to look at this exception throwing problem again
      /*
      if (newValue == null) {
      return TCL_ERROR;
      }
      */

      // Set the interpreter's object result to refer to the variable's new
      // value object.

      interp.setResult( newValue );
      return TCL.CompletionCode.RETURN;
    }
  }
}