while (a=b()) ...

[Tim Peters]

[Dan Schmidt]
> ...
> One thing which Knuth's construct (actually, he stole it from Zahn)
> has that Halaas' lacks is the ability to catch the break-exceptions
> from outside the loop, along with information associated with the
> exception.
> ...
> I've never had the opportunity to use any of these constructs, so I
> have no opinion on which is better :)

Zahn's loops in full-blown form were a feature of SKOL, a high-level
language implemented via an incredibly powerful and incredibly slow macro
preprocessor whose output was Fortran.  I used this in the mid 70's (in
fact, if you get hold of an old Cray Fortran manual, you can find docs for
the "IMPLICIT SKOL" stmt I added to Cray's Fortran to support this -- its
meaning was "gripe about all undeclared variables, except for those whose
names begin with 'I00', which are implicitly INTEGER" <yikes!>).

Gimmick-laden looping constructs were trendy back then.  I expect they met
the fate they deserved.

although-i-deserved-much-better<wink>-ly y'rs  - tim