[Nickle] Scope for condition of do while

Bart Massey bart at po8.org
Fri Feb 1 19:56:17 PST 2008

In message <871w7wupqa.wl%cworth at cworth.org> you wrote:
> Should this be a legitimate thing to do?
>     do {
>         putchar (int c = getc (socket));
>     } while (c != '.');
> That is, should the while condition share scope with the block above
> even though it's syntactically outside?
> Keith whipped up a special-case implementation of this, but he's
> definitely not sure that it's not a horrible idea. He's planning to
> cogitate a bit more, so I'm just sending this to remind him to type
> his thoughts at some point, and also to solicit any other thoughts
> others might have.
> -Carl

Note that if you replace '.' with EOF in your example, it
breaks it.  Normally one would have to write something like

  while (true) {
    int c = getc(socket);
    if (c != '.')

On the other hand, our try scoping hack set the precedent
that it's OK to continue the scope a ways after the block.

  try {
    int c = getc(socket);
  } catch io_error(e,s,f) {}
  if (c != '.')

The above is legal.  Maybe do should be special too.


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