foreach ... else statement

[Walter Bright]

grauzone wrote:
> bearophile wrote:
>> Don:
>>> Actually Walter loves goto, so DMD copes really well with it.
>>
>> When possible it's better to use structured programming and avoid 
>> gotos. That construct can avoid gotos in some common situations.
>> And regarding the compiler back-end, I think it's also better to start 
>> thinking what's good for LDC :-)
> 
> I don't know how relevant this is, but: LLVM uses SSA for registers, and 
> it seems to be simpler to convert code to SSA if there are no gotos:
> 
> "We show that it is possible to generate SSA form in a single pass (even 
> during parsing) if the program contains only structured control flow 
> (i.e., no gotos). For such programs the dominator tree can be built on 
> the fly, too."
> 
> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.45.4503

I don't know what they're talking about. The D optimizer has no trouble 
whatsoever building dominator graphs, no matter what rat's nest of gotos 
are used. This technology was well understood in 1980.

In fact, the front end deconstructs *everything* into gotos, and that's 
all the optimizer works with.