[Info-vax] BASIC (and Horizon)

[Dave Froble]

On 2/1/2024 9:49 PM, Arne Vajhøj wrote:
> On 1/31/2024 9:49 PM, Lawrence D'Oliveiro wrote:
>> On Wed, 31 Jan 2024 19:29:14 -0500, Arne Vajhøj wrote:
>>> That code would look a lot cleaner if the do while(false) loop got
>>> removed and the relevant breaks got replaced by goto's.
>>
>> Show us how you would do it. I can take you through my code step by step,
>> block by block, if that will help.
>
> It is pretty simple.
>
>     do {
>         allocate(o1);
>         ...
>         if(...) break;
>         ...
>     } while(false);
>     deallocate(o1);
>
> can be done as:
>
>     allocate(o1);
>     ...
>     if(...) goto cleanup;
>     ...
> cleanup:
>     deallocate(o1);
>
> The first piece of code is pretty bad as it confuses the
> reader by using a loop and the break is not very
> self documenting.
>
> The second piece of code is straight forward to read
> despite using goto.
>
> It gets even more clear in the nested case.
>
>     do {
>         allocate(o1);
>         ...
>         if(...) break;
>         ...
>         flag = FALSE;
>         do {
>             allocate(o2)
>             ...
>             if(...) {
>                 flag = TRUE;
>                 break;
>             }
>             ...
>         }
>         deallocate(o2)
>         if(flag) break;
>         ...
>     } while(false);
>     deallocate(o1);
>
> vs:
>
>     allocate(o1);
>     ...
>     if(...) goto cleanup_1;
>     ...
>     allocate(o2);
>     ...
>     if(...) goto cleanup_1_and_2;
>     ...
> cleanup_1_and_2:
>     deallocate(o2);
> cleanup_1:
>     deallocate(o1);
>
> The nested do while loop is a big mess. The goto solution
> is still simple.
>
> Arne
>

Well, I'd use:

Select <something>
	Case = "1"
		Some code
	Case = "2"
		Some other code
End Select

No need for the dreaded GoTo statement  ...

But even that can be abused.

Got a friend that got carried away with Select and indenting.

When the Select statements got nested a dozen times, and indents became 8-10 
tabs, and the code for each CASE was several pages long ...

If the damn code was going to be so massive and complex, he should have just 
branched/performed/whatever to a separate place to do all that work.


-- 
David Froble                       Tel: 724-529-0450
Dave Froble Enterprises, Inc.      E-Mail: davef at tsoft-inc.com
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