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- Subject: Re: New scoping rule for "repeat" and "continue" patch
- From: Doug Rogers <rogers@...>
- Date: Wed, 05 Oct 2005 09:35:17 -0400
David Given wrote:
> It's interesting to note that old versions of the [C++] standard decreed
> that the scope of the loop variable extended until the end of the
I remember that transition, too.
Though my vote is meaningless, I vote for the local scope. The
interpreter should use a variable local to the 'repeat-until' block if
it appears in the 'until' clause - even if that makes it difficult to
create a 'continue'.
For what it's worth, I think Ada does the whole looping business
properly, though Ada does not allow declarations in the middle of a code
block, nor does it support 'continue'. Ada's approach to scoping for a
repeat loop is closer to Rici's - do not even provide a conditional at
the end of the loop:
exit when K < 0; -- Exits the innermost containing loop.
I := K ** 3;
K := I + 1;
Put_Line ("I K =>" & I'Img & K'Img);
exit Outer when I > 15;
end loop Outer;
If we could start over, then my vote would be to exclude the 'repeat
block until exp' construct from the language entirely in favor of a new
'break' that supports optional loop names and conditionals - or some
syntactic sugar for the latter.
But that's a topic for another thread.
Doug Rogers - ICI - V:703.893.2007x220 www.innocon.com