Computer Science Canada

Exit statement for procedures
Author:  Tallguy [ Tue May 05, 2009 8:54 am ]
Post subject:  Exit statement for procedures
i'm wondering if its possible to exit a procedure that doesn't have any conditional or normal loops in it. such as..

Turing:

proc main
%code
exit if /*something = true*/
end main


any ideas?
Author:  [Gandalf] [ Tue May 05, 2009 9:07 am ]
Post subject:  RE:Exit statement for procedures
Usually you just let the procedure evaluate to the end, and then it 'exits' on its own. If you need to prematurely exit, you could use a empty return statement... Though this shouldn't really be necessary.
Author:  Tallguy [ Tue May 05, 2009 9:29 am ]
Post subject:  Re: Exit statement for procedures
what i mean is in using an recusive programing where the procedures calls itself to run such as

Turing:

setscreen ("graphics:500,500") %set screen to a specfic size
proc draw (x, y, x2, y2 : int) %declares a proc with prameters
    drawbox (x, y, x2, y2, 12) %Draw the box
    delay (500)
    draw (x + 10, y + 10, x2 - 10, y2 - 10) %recursion re-call proc to run
end draw

draw (10, 10, 490, 490) % calls the proc to run


and lets say you want the program to stop when the box is a certain size, to exit, not using any type of loop...any ideas?
Author:  Dusk Eagle [ Tue May 05, 2009 9:59 am ]
Post subject:  Re: Exit statement for procedures
Turing:

if /*condition*/ then
    return
else
    %call procedure again
end if
Author:  [Gandalf] [ Tue May 05, 2009 10:25 am ]
Post subject:  RE:Exit statement for procedures
Or rather:
code:
proc ...
    if box not certain size then
        current body of proc
    end if
end ...

You really shouldn't use return when you're not explicitly returning something, as in a function.
Author:  Dusk Eagle [ Tue May 05, 2009 2:46 pm ]
Post subject:  Re: Exit statement for procedures
Yes, but since he specifically asked for it, I showed how it worked. I agree that you should avoid preemptively ending your procedures like above.
Author:  Euphoracle [ Tue May 05, 2009 3:53 pm ]
Post subject:  Re: RE:Exit statement for procedures
Gandalf @ Tue May 05, 2009 10:25 am wrote:
Or rather:
code:
proc ...
    if box not certain size then
        current body of proc
    end if
end ...

You really shouldn't use return when you're not explicitly returning something, as in a function.


Return isn't for returning a value in turing, result is. Return is for terminating a procedure prematurely.

Alternatively, you could simply not call the procedure again by checking whether or not it will be done at that stage.
Author:  [Gandalf] [ Tue May 05, 2009 4:02 pm ]
Post subject:  Re: RE:Exit statement for procedures
Euphoracle @ 2009-05-05, 3:53 pm wrote:
Return isn't for returning a value in turing, result is. Return is for terminating a procedure prematurely.

My bad, I'd forgotten. Nevertheless, the same hold true for its use. There's no reason to be using return, in this situation or pretty much any other. It's like going back to goto... You could, but it's only going to make your code sloppier.

Euphoracle @ 2009-05-05, 3:53 pm wrote:
Alternatively, you could simply not call the procedure again by checking whether or not it will be done at that stage.

Yes, this is what I mentioned.
Author:  BigBear [ Tue May 05, 2009 10:02 pm ]
Post subject:  RE:Exit statement for procedures
A procedure will follow through the code and leave the procedure
Author:  Insectoid [ Wed May 06, 2009 10:36 am ]
Post subject:  RE:Exit statement for procedures
The idea is not to end the procedure via a conditional, but to use a conditional to keep it going. It will naturally end then if the conditional returns false.
code:

%instead of

proc bleurgh
    put "Blablabla"
    exit bleurgh when foo = baz
    bleurgh
end beurgh

%do

proc bleurgh
    put "Blablabla"
    if foo ~= baz then %"~=" is the same as "not equals" or "!=" (!= will not work in Turing)
        bleurgh
    end if
end bleurgh

:


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