Re: [fpc-pascal] Legitimate use of for and break
> On Jul 2, 2023, at 3:25 AM, Steve Litt via fpc-pascal > wrote: > > I tend to put continue statements at or near the top of the block, to > summarily rule out some obvious irrelevant iterations without all sorts > of if/then/else nesting. As a practical matter it's more readable and > more maintainable. Swift has decided to build this pattern into the language. I kind of like it but it's also kind of messy looking and a continue at the top of the block often is easier to read for me. In pascal it would look like this: for item in list where item.value > 10 do begin end; Which would be the same as: for item in list do begin if item.value <= 10 then continue; end; or with traditional for loops but this really looks bad. for i := 0 to list.Count - 1 where list[i] > 10 do begin end; Regards, Ryan Joseph ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Legitimate use of for and break
Santi via fpc-pascal said on Sat, 1 Jul 2023 10:22:48 +0200 >El 16/06/2023 a las 16:09, Mattias Gaertner via fpc-pascal escribió: >> On Fri, 16 Jun 2023 20:51:42 +0700 >> Hairy Pixels via fpc-pascal wrote: >> On Jun 16, 2023, at 6:23 PM, Thomas Kurz via fpc-pascal wrote: >> 20 years ago there were some programmers, claiming a loop condition >> must only be at start or end, but not in the middle. >I mostly agree with that programmers. That's called structured >programming. "Break" and "continue" are in fact, a subset of GOTO I agree, although they're less damaging than goto, which I haven't used since 1982 using 6800 hex machine language, where I learned how much less damaging jump to subroutine and return from subroutine are than goto. >When you see a structure, a block, you know at the beginning (or end >of the block) the exit conditions. So you can skip the block and you >know the conditions after the block. It is very useful when you are >skimming the code or debugging. You don't have the investigate the >inner loop to see if there are hidden GOTOs. I agree, although there are some practical concerns, which you go on to mention... > >But, as any other golden rule, you must know when it makes sense to >ignore it. >I use the break, but only at the beginning of the loop. (or exit in >function/procedure) >And sometimes with deep nested loops, but, when I commit such crime, I >highlight it with neon lights in the comments. I tend to put continue statements at or near the top of the block, to summarily rule out some obvious irrelevant iterations without all sorts of if/then/else nesting. As a practical matter it's more readable and more maintainable. Also, when I'm in a rush, I'll do while(True) and then just put one or more breaks in the block, with the full intention of going back and doing it the right way, but then forget to. I apologize to the maintenance programmer who follows me, because this is bad practice. Sometimes I use breaks when the loop test condition would be so hairy as to be difficult to understand. This happens a lot when things get very stateful. But your post got me to thinking that maybe this is a symptom that I made a poor design. > >I really hate having the read the full code to guess whats happening. >Structured programming is your friend. Xactly! SteveT Steve Litt Autumn 2022 featured book: Thriving in Tough Times http://www.troubleshooters.com/bookstore/thrive.htm ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] Legitimate use of for and break
El 16/06/2023 a las 16:09, Mattias Gaertner via fpc-pascal escribió: On Fri, 16 Jun 2023 20:51:42 +0700 Hairy Pixels via fpc-pascal wrote: On Jun 16, 2023, at 6:23 PM, Thomas Kurz via fpc-pascal wrote: Whether it's elegant is a different question. In my opinion YES because it often gives better readable code than nested "if" statements inside the loop. But I've also read that using "break" is discouraged because it shows a bad choice of the loop range. This is highly suspect. Doing an early break in loops is the essence of how to do linear searching. No idea who thinks that's a bad idea. 20 years ago there were some programmers, claiming a loop condition must only be at start or end, but not in the middle. I mostly agree with that programmers. That's called structured programming. "Break" and "continue" are in fact, a subset of GOTO When you see a structure, a block, you know at the beginning (or end of the block) the exit conditions. So you can skip the block and you know the conditions after the block. It is very useful when you are skimming the code or debugging. You don't have the investigate the inner loop to see if there are hidden GOTOs. But, as any other golden rule, you must know when it makes sense to ignore it. I use the break, but only at the beginning of the loop. (or exit in function/procedure) And sometimes with deep nested loops, but, when I commit such crime, I highlight it with neon lights in the comments. I really hate having the read the full code to guess whats happening. Structured programming is your friend. Gladfully, most programmers came to their senses. Mattias ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal -- Saludos Santi ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
