OpenEuphoria

Re: goto's, and loops

• Posted by Roderick Jackson <rjackson at CSIWEB.COM> Jul 29, 1999
• 520 views

Hi Kat,

If I read Rob (and the language) correctly, one of the guiding principles
of Euphoria is that a programmer shouldn't do something that others (or he
himself, later on) will find extremely difficult to understand, debug or
change. This is part of "the Euphorian philosopy" of coding, language design,
and programming in general.

Now, I've seen examples where gotos have been used in code without being at
all troublesome, fitting cleanly in the algorithm. But, the potential for
abuse with the goto statement is absolutely monstrous. Sure, it CAN be used
well; but remember the Euphorian philosophy. When I was introduced to the
concept of structured programming (while using BASIC), I started trying to
NOT use gotos, and it helped my coding. It was easier for me to remember
what my code did, and it helped organize my code into logical subsections.

Rob's decision to leave out the goto does have a number of advantages, and
fits with the Euphorian philosophy. Since using QBasic and becoming more
experienced with program flow, I haven't missed it. It might take some
getting used to, but you'll find that anything that can be done with a goto
can be done without; of course, in some cases the goto is just plain easier
to use. 

As to your example... the short answer would be "redesign the algorithm,"
but that's not always desireable. One specific approach would be to leave
the code pretty much the way it is, but use local variables to store
certain states. The result would look something like:

   ConditionFlag = 0 -- this is FALSE

   for i = w to x do

       -- some code

      for j = y to z do
         if (s[i][j] = 0) then
            ConditionFlag = 1 -- this is TRUE
            exit
         end if
      end for

      if (not (ConditionFlag)) then
         -- more code
      end if

   end for


Hope this helps you out some...


Rod

----------
From:   Kat[SMTP:KSMiTH at PELL.NET]
Sent:   Thursday, July 29, 1999 10:49 AM
To:     EUPHORIA at LISTSERV.MUOHIO.EDU
Subject:        goto's, and loops

Hi all,

Why is there no "goto" in Euphoria? It would be easy enough to implement,
and if you don't want to use it, you don't haveto. I've used it sparingly in
other languages, for the example below, for example. Maybe i am in a rut,
but i don't see an nice way to do this example in Euphoria, can you help,
please? ( Without making another procedure and all the vars global. )

loop1
some code
loop2
test var, maybe goto target
-- an "exit" here would get you out of loop2, not loop1
EndOfLoop1
more code
EndOfLoop2
:target

thanks,
Kat