On 01/09/2008 10:06 AM, Martin Rubey wrote:
> Ralf Hemmecke <[EMAIL PROTECTED]> writes:
>
>>> No, sorry. As far as I know, in SPAD,
>>>
>>> => iterate (in fact, not sure about that one)
>
>>> => "iterate"
>
>> So in
>>
>> for a in list repeat (x; condition => somevalue; y)
>>
>> somevalue is irrelevant. This form just says that y is not
>> evaluated if condition is true.
>>
>> Clearly, in a loop all forms except "=> iterate" are confusing.
> I'm not so sure. I think, the intention of iterate is different --
> iterate jumps to the next element of the loop, no matter in which
> block it currently is. At least, that's the semantics in Aldor, if I
> understand correctly.
Indeed. You are right. Look at the difference of the output of
---BEGIN aaa.as
#include "aldor"
#include "aldorio"
main(): () == {
b: Integer := 0;
for i in 1..3 repeat {
stdout << i << "A" << newline;
{
stdout << i << "B" << newline;
#if ITERATE
i > 1 => iterate;
#else
i > 1 => "iterate";
#endif
stdout << i << "C" << newline;
}
stdout << i << "D" << newline;
}
}
main();
---END aaa.as
woodpecker:~/scratch>aldor -grun -laldor -DITERATE aaa.as
1A
1B
1C
1D
2A
2B
3A
3B
woodpecker:~/scratch>aldor -grun -laldor aaa.as
1A
1B
1C
1D
2A
2B
2D
3A
3B
3D
But clearly, the form
=> "iterate"
or
=> nil
is misleading. Better is to write:
=> "Please think carefully what happens here."
;-)
> Any other candidates for the name contest? Maybe nil? (also used
> sometimes)
I only support iterate as a keyword. Anything else is confusing, because
one would have to give a value where none is needed.
In the example above (case "iterate") instead of
{
stdout << i << "B" << newline;
i > 1 => "iterate";
stdout << i << "C" << newline;
}
one should rather write a not so confusing form...
{
stdout << i << "B" << newline;
if not (i > 1) then stdout << i << "C" << newline;
}
Ralf
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