missing ->= operator

[Doug Gwyn]

In article <1991Apr30.165110.4165 at unhd.unh.edu> jwm712 at unhd.unh.edu (Jonathan W Miner) writes:
>It is my opinion that the +=, &= etc operators were implemented on systems,
>such as DEC VAX that has two operand instructions.  Although it would
>be nice to have a ->=, it would be a programmer convenience, and it would
>still be compiled into the same code as p = p->next.  

No, you're not supposed to be thinking about what code is going to be
generated.

The main advantage of op= occurs in situations like:

	p->link->data[BIG_ROOM].flags |= BEEN_HERE;

where it would be tedious and error-prone to have to duplicate the LHS
as an operand, which would be necessary if the op= form did not exist.

There is no such justification for ->=, which seldom would be used in
contexts more involved than

	p = p->next;

which is easy enough to code as is.

There are some other more technical reasons involving type compatibility,
etc. but the above argument shows that it is not worth doing.