public ActionMBStringExtract()
{
_StackOps = new StackChange[ 4 ];
_StackOps[ 0 ] = new StackPop( AVM1DataTypes.AVM_String ); // count
_StackOps[ 1 ] = new StackPop( AVM1DataTypes.AVM_String ); // index
_StackOps[ 2 ] = new StackPop( AVM1DataTypes.AVM_String ); // the string
_StackOps[ 3 ] = new StackPush( AVM1DataTypes.AVM_String ); // the substring (result)
}