#define IS_IFX(ex) (ex->type == EX_OP && ex->opval.op == IFX )
#define IS_LT(ex) (ex->type == EX_OP && ex->opval.op == '<' )
#define IS_GT(ex) (ex->type == EX_OP && ex->opval.op == '>')
-#define IS_NULLOP(ex) (ex->type == EX_OP && ex->opval.op == NULLOP)
/*-----------------------------------------------------------------*/
/* backPatchLabels - change and or not operators to flow control */