On Thu, 2009-04-23 at 10:14 -0400, tedd wrote: > At 2:19 PM +0100 4/23/09, Tony Marston wrote: > >"tedd" <tedd.sperling@xxxxxxxxx> wrote in message > > > It's called "Structured programming" -- one way in and one way out of a > >> function. > >> > >> There are, of course, exceptions where it might help others reviewing your > >> code to see what's going on, such as returning a null value if the > >> argument(s) provided are not suitable. But normally the rule is, do not > >> provide an exit from a function in more than one place. > > > >There is no such "rule", it is a matter of personal preference. As a > >previous poster has already said, if you want to leave a function early and > >ignore all subsequent processing it is easier to understand if you return > >immediately rather than have a mechanism to jump over the remaining code to > >a single return point. In the good old days we used to use the GOTO in COBOL > >to jump to the exit point, but then people found a way to abuse GOTO in very > >imaginatve ways. > > > >> The "benefit" is easier to read code. > > > >I think that an immediate return is easier to read, but what do I know - > >I've only been programming for 30 years. > > > >-- > >Tony Marston > > Tony: > > Don't get your panties in a knot. :-) > > I have 44 years of programming under my belt, so what? However, I > wish I could remember everything I learned during that time. > > But what I do remember is there's a school of thought called > "Structured Programming" that has a doctrine in which every function > should have only one entry and exit point. > > Now maybe you want to argue with that concept, that's fine -- but the > point remains this is a "rule" under "Structured Programming". That's > history. > > Now, I usually follow that rule for I have learned from experience > that in most cases, it is easier to read what is going on in a > function if you only have one exit. > > As I said in my post, there are of course exceptions. There are times > that requiring a function to have a single exit point will > unnecessarily create code that's hard to read -- so doing it > differently is something to consider in those cases. If you want to > have an immediate exit point in your functions and that makes your > code more readable, then that's fine and I'm not arguing that point. > > However, I am saying (after years of reading other people's code) it > is generally much easier to read code that follows "Structured > Programming" than it is to read code that doesn't. Actually I use an early return as much as possible also. If there are 5 conditions which disqualify the rest of the function from running then they'll all be listed one after the other at the top of the function. This way it's very easy to see exactly what doesn't qualify for evaluation. Additionally, it saves on the need for that many levels of indentation or making an overly complex conditional. I find it much more intuitive than mentally tracking several levels of indentation and scrolling to the bottom of the function. Cheers, Rob. -- http://www.interjinn.com Application and Templating Framework for PHP -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
