It's that stupid single exit point from a function

Post #287,583

6/21/07 11:35:13 PM

I always though PASCAL what very much like C, except braces were words.

Except for the single exit rule.

It claims to save the confusion of figuring out what bit of code did the return, but it adds lots of complexity / if/then/elses / gotos (gasp) to every friggen function to get around it.

Post #287,765

by jb4

6/24/07 10:21:48 PM

I've got NO PROBLEM with that

In fact, every coding standards/guidelines that I have anything to do with routinely prescribe "every block should have one way in, and one way out" Not a big fan of trap door exits, you see....

jb4
"It's hard for me, you know, living in this beautiful White House, to give you a firsthand assessment."
— George W. Bush, when asked if he believed Iraq was in a state of civil war (Newsweek, 26 Feb 07)

Post #287,769

by crazy

6/24/07 11:34:38 PM

You ever have nested while and for loops?

With a decision or 2 inside it?

Single point of exit either requires numerous flag variables that have nothing to do with the program logic - they are there as an artifact of the language itself. Additional tests at each loop level to determine whether you broke out of the loop via a decision in the loop or a loop fall out.

Or, shudder - goto - that bounces you to the bottom.

Or, my favorite solution, named loops and a "last NAME;" statement, which allows a clean breaking out of nested loops.

Whether or not you have a problem with this is not the issue. I've seen a far better way and now know better. Far less code, much cleaner and easier to code and maintain.

Post #287,981

by jb4

6/27/07 9:21:29 PM

"Numereous flags"

mah-noor. Except in some very unusual circumstances, the exit can be controlled by exactly 1 flag. And by namingthe flag correctly (e.g. something like failure or done ) it might even self-document.

The answer to your question is yes. Now I got one for you: Ever debugged/refactored a 16-greenbar-page function cock-full of trapdoor exits, and where you get to page 14 or so and have absolutely no idea what the conditions are that have gotten you to this place in the code, because the berk who wrote it was overly enamored with taking his/her ball and bat and going home at the slightest provocation?

Didn't think so...

Post #287,982

by crazy

6/27/07 9:46:24 PM

Didn't think so?

Hah.

Wimp.

[link|http://z.iwethey.org/forums/render/content/show?contentid=266834|http://z.iwethey.org...?contentid=266834]

Just because some idiot uses certain features unwisely does not mean the language should be designed for the idiot.

Because if you really want to split hairs on this one, I've got some stories of longjmp usage.

Or in MS-DOS days, poking a few values in a certain register and jumping to zero. hhhheeeeeeheheheheehe. Warm boot from my program as a last ditch effort.

Sometimes when you setup public workstations that's all you can do.

Post #288,104

by static

6/29/07 6:00:12 PM

That's a good way out.

Although it sometimes feels a little clunky. However, sometimes that's all the language has available.

I like Icon's approach. It's a bit tricky to describe but the idea is that you can pass breaks up several layers all at once. And you can make the last one do a next, instead. It's really elegant. However, due to other qualities of the language, it doesn't get used all that much. This is because things like goal-directed evaluation and expression back-tracking and generators are usally used to implement the kind of logic and loops that people need to put in trap-door exits for. :-/

Wade.

Is it enough to love
Is it enough to breathe
Somebody rip my heart out
And leave me here to bleed

Is it enough to die
Somebody save my life
I'd rather be Anything but Ordinary
Please

-- "Anything but Ordinary" by Avril Lavigne.

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