On Tue, Jul 28, 2009 at 5:46 PM, Stewart Gordon<[email protected]> wrote: > Jarrett Billingsley wrote: >> >> Tue, Jul 28, 2009 at 2:28 PM, Arthur Lloyd<[email protected]> wrote: >>> >>> Daniel Keep Wrote: >>> >>>> U comma(T,U)(T a, U b) { return b; } >>>> >>>> Is there any reason you couldn't use something like that? >>> >>> Sorry, this is probably a newbie question, but.. So instead of return a, >>> b, c; you now have to write return comma(a, comma(b, c)); ? How will that >>> help? >>> >> >> typeof(T[$ - 1]) comma(T...)(T args) { return args[$ - 1]; } >> >> There. Now you can do "comma(a, b, c)". > > Still won't solve the problem Andrei rightly pointed out. But this will: > > T[$-1] comma(T...)(lazy T args) { > foreach (a; args[0..$-1]) cast(void) a; > return args[$-1]; > }
For one, that's almost verbatim what Tom S suggested in "comma expressions must die." For two, what problem did Andrei point out? Order of evaluation of function arguments? On the contrary, he said "now that order of evaluation will be defined to be left-to-right in D, the semantics would be quite the same". Your code is what you'd have to use in D1, but in D2, the simpler version would suffice.
