1. Loop
I would like to suggest that Euphoria should have loop-end loop.
It looks more clear and possibly runs a little faster
(since it doesn't has to check if 1 is true or not).
Instead of:
while 1 do
do_something
if something_is_true then exit end if
end while
It should be this:
loop
do_something
if something_is_true then exit end if
end loop
Dan-Åke Engqvist
2. Re: Loop
Dan-Åke Engqvist wrote:
>
> I would like to suggest that Euphoria should have loop-end loop.
> It looks more clear and possibly runs a little faster
> (since it doesn't has to check if 1 is true or not).
>
> Instead of:
> while 1 do
> do_something
> if something_is_true then exit end if
> end while
>
> It should be this:
> loop
> do_something
> if something_is_true then exit end if
> end loop
>
> Dan-Åke Engqvist
This optimisation is already being performed.
If you look at the emit.e file in the source directory, you'll see that,
when the conditional clause of a while statement is a nonzero constant,
the code which checks the condition on each loop iteration is not generated,
hence is not executed. This optimisation is mentioned in the release notes.
As to whether "while 1 do" is clearer than "loop"... The latter is shorter,
so it is better. This is typically the sort of things a preprocessor would do,
but there is no official preprocessor for Eu. There are a few in the archive.
CChris
3. Re: Loop
CChris wrote:
>
> Dan-Åke Engqvist wrote:
> >
...
>
> This optimisation is already being performed.
>
> If you look at the emit.e file in the source directory, you'll see that,
> when the conditional clause of a while statement is a nonzero constant,
> the code which checks the condition on each loop iteration is not generated,
> hence is not executed. This optimisation is mentioned in the release notes.
That's good
> As to whether "while 1 do" is clearer than "loop"... The latter is shorter,
> so it is better. This is typically the sort of things a preprocessor would do,
> but there is no official preprocessor for Eu. There are a few in the archive.
>
> CChris
"loop" is better, but not because it is shorter. It just tell the program what
to do. "while 1 do" tell the program to do something if something that always
is true is true.
Now another loop: for-end for
for s={i1,j1,...} to {i2,j2,...} by {k1,k2,...}
...
end for
Would this be a good idea as an alternative to nested loops?
/Dan-Åke Engqvist
4. Loop
Is there any command to cause a program to loop over and over until control+c
is pressed?
5. Re: Loop
Hello,
>Is there any command to cause a program to loop over and over until
control+c
>is pressed?
I believe that putting the whole prog in this loop should do the trick:
integer k
while 1 do
-- program code or main procedure
k = get_key()
end while
I think that ctrl+C will exit any Euph prog while it is looking for
keyboard input. At least ctrl+break should work. There may even be a
simpler way to do this but I can't test it on my mailer.
Lewis Townsend
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6. Re: Loop
- Posted by Robert B Pilkington <bpilkington at JUNO.COM>
Sep 08, 1998
-
Last edited Sep 09, 1998
>>Is there any command to cause a program to loop over and over until
>control+c
>>is pressed?
>
>I believe that putting the whole prog in this loop should do the
>trick:
>
>integer k
>while 1 do
>-- program code or main procedure
>k = get_key()
>end while
>
>I think that ctrl+C will exit any Euph prog while it is looking for
>keyboard input. At least ctrl+break should work. There may even be a
>simpler way to do this but I can't test it on my mailer.
Try this (untested) code:
include machine.e -- allow_break()
allow_break(0) -- CTRL-BREAK won't cause program to up and,
-- for all intents and purposes, crash.
integer key
while 1 do
key = get_key() -- Get input
if check_break() then -- CTRL-BREAK or CTRL-C found
exit -- Exit loop
end if
end while
-- Exit gracefully here (restore video mode, close files, etc)
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