LLVM Coding Standards

[spir]

On 04/12/2011 03:15 AM, Daniel Gibson wrote:
>> While I am on the subject, I've *always* thought major languages have
>> >  poor loop constructs:
>> >
>> >
>> >  (A)
>> >
>> >  for (;;)
>> >  {
>> >       std::getline(is, line);
>> >       if (line.size() == 0)
>> >           break;
>> >       ...some things...
>> >  }
>> >
> (...)
>> >
>> >  Instead you could just have:
>> >
>> >  loop
>> >  {
>> >    ...
>> >    if (condition) exit;
>> >    ...
>> >  }
>> >
>> >  instead of WHILE and DO. Whereby you *must* have an exit condition.
>> >
>> >
>> >  But I suppose you need a FOR loop because the following may be error prone.
>> >
>> >  int x=0;
>> >  loop
>> >  {
>> >  if x>  9 exit;
>> >  ...
>> >  x++;
>> >  }
> Yeah. And I guess while-loops also have their uses.
> I think just loop like you're suggesting is not available because
> for(;;) and while(1) achieve the same thing without too much additional
> typing.

I've been thinking of a loop construct allowing either while or until, each 
either at start or end, or even both:

     loop [(while|until) condition] {
         body
     } [(while|until) condition]

Side-Note: I favor until over while because I "feel" (for what reason?) 
booleans should be initially false, or false by default, thus the end-condition 
should express a change and be positive.

     loop until end1 {
         body
     } until end2

ends are initially false

     loop while end1 {
         body
     } while end2

ends are initially true

Denis
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