generalized switch

[Tainter]

> Sure, that's the way I have been doing it. But you can do that with
> any choice among cases.
> As I understand it, a switch/case setup compiles exactly the same as
> 	if (var == const1) {.....};
> 	else if (var == const2) {.....};
> 	else  {default_action};
> anyway. (Or am i wrong?). In any case, it can be rewritten that way.
> Joshua Kosman
> kos at ernie.berkeley.EDU

You are wrong.
switch (a) {
    case 'a': hi();
    case 'b': ho(); break;
    case 'c': he();
    case 'd': ha(); break;
}
.  .  .

can be written as:
if (a == 'a') {	
    hi(); goto do2; /* skip the test on 2 */
}
if (a == 'b') {
do2:
    ho(); goto done;	/* do a break */
}
if (a == 'c') {
    he(); goto do4; /* skip the test on 4 */
}
if (a == 'd') {
do4:
    ha(); goto done; /* do a break */
}
done:
.  .  .

A bit different than the simple if else block, ja?
The switch statement can also be coded as a jump table with generaly better
performance than the if else block.

It might be feasable to fold if else blocks testing the same variable repeatedly
into a jump table, but I'll wager it's unusual.
--j.a.tainter