发自我的 iPad > 在 2014年7月28日，22:20，Andrea Faulds <a...@ajf.me> 写道： > > > On 28 Jul 2014, at 15:00, Derick Rethans <der...@php.net> wrote: > >>> Well, we don’t need to allow all of C99. We can simply allow using >>> features that are widely supported and actually useful. For example, >>> declarations between statements, >> >> I think that makes code a lot less readable, so I would not be in favour >> allowing this in our coding guidelines. > > Really? I’ve found that declaring everything in advance makes for > hard-to-read code. To take an example from code I’ve written (admittedly not > C code - GML if anyone’s curious - but it might as well be), the first line > of a function looked like this: > > var list, hashList, text, i, pluginname, pluginhash, realhash, url, > handle, filesize, progress, tempfile, tempdir, failed, lastContact, isCached, > env; > > Even broken onto multiple lines, declaring everything at once isn’t nice. For > large functions (and some functions have to be large necessarily), declaring > everything at the start just means a long list of variables and I would argue > impairs code readability. > > You should declare variables when and where you need them. If everything is > done at the top, you have to scroll up to check the type of a variable. It > also means that now-unused variables are less obvious as the declarations are > far away from the usage, so you probably won’t spot that it’s useless unless > you look at your compiler warnings. > > Actually, a similar issue popped up in the code where that example was from. > The language it was written in had some unfortunate properties, one of which > was that variables not explicitly declared would instead be treated as > properties of the current object. Because all the variables were declared at > the start of the function, it was easy to miss the fact that some variables > being used had not actually been declared. Of course this specific issue > doesn’t exist in C, but it is an example of why having to declare all your > variables at the start of a function isn’t really a good thing. > > If nothing else, I think we should use C99’s ability to declare variables > between statements. It makes it more likely mistakes will be spotted, eases > reading code, and as far as I am aware, is widely supported. I really hate this. Thanks > > -- > Andrea Faulds > http://ajf.me/ > > > > > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php >
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