Re: 2 Questions: Static variables and the nature of the online manual

Ok Jochem, It makes a lot of sense. Now I know what I can expect from the manual and what kind of approach I should have. I hope to contribute as well in the future. Many thanks, S In 4/3/08 16:11, Jochem Maas, jochem@iamjochem.com ha scritto > Svevo Romano schreef: >> Hi there, >> >> Many thanks for your answer. I've also gone through your example and it took >> me 10 minutes to understand how the operator precedence was working there. >> Was expecting 1 on the first call :) >> >> But this is not the point. You've nailed my question very preciseley in your >> first answer: 'the preceding line is only run on the first call to the >> function'. >> >> My only question is (at it is related to the nature of the online manual): >> how do you know it and I don't? This thing is the only logical explanation >> to the fact the $a doesn't get initialized again to 0 in any subsequent call >> to the function, but it's not written anywhere in the manual page. And it >> seems the most important statement in my opinion, that justifies what I see >> as an exception to a normal flow. > > can't remember where I picked up the meaning/working of 'static' - I think I > just worked it out by trial and error, or I read about it sometime on this > list :-) > > the manual does talk about statics: http://php.net/static > > notice you can type 'http://php.net/<FOO>' to > go straight to certain docs, > replace > <FOO> with a function name, extension name, core concept, or whatever ... if > nothing > is found you get a 'did you mean ....?' type page otherwise you go directly to > the > relevant manual page. > >> >> Hope all this makes sense. >> Thanks, >> S >> >> In 4/3/08 13:14, Jochem Maas, jochem@iamjochem.com ha scritto >> >>> Svevo Romano schreef: >>>> Hello, >>>> >>>> I got this e-mail address from the ŒAdd note¹ page within the php.net >>>> website. I was going to post something that was a question and I realised I >>>> was in the wrong place :) >>>> >>>> I have 2 basic questions and I¹m sorry if they may seem too basic. I¹m a >>>> bit >>>> new to php. >>>> >>>> The first question has to do with the static variables. I understand how >>>> this works from the examples, but there is something that I cannot seem to >>>> find clearly stated anywhere on that page. >>>> >>>> The example: >>>> >>>> <?php >>>> function Test() >>>> { >>>> static $a = 0; >>> the preceding line is only run on the first call to the function. >>> >>>> echo $a; >>>> $a++; >>>> } >>>> ?> >>>> >>>> Of course works (I¹ve tested it on my server), but it is still obscure to >>>> me, according to general programming principles, since I¹m still assigning >>>> zero (0) to $a on each call to the Test function. How does this exactly >>>> work >>>> when the static word is found? Is there and index that keeps track of each >>>> call to the function ignoring any assignment in subsequent calls to the >>>> function? Why doens¹t this work when you assign an expression result to the >>>> variable? >>> do something like >>> >>> function Test() >>> { >>> static $a; >>> >>> if (!isset($a)) >>> $a = 0; >>> if ($a % 2) >>> $a = $a * 2; >>> >>> echo $a++; >>> } >>> >>>> The second question has to do with the online manual. I¹ve found several >>>> things on that manual specified in comments and not in the actual manual >>>> part of it. What is the nature of the manual? Contributions from voluteers? >>>> Is there any official manual I can buy that documents everything about the >>>> language from the source? Or any official company that maintains the >>>> language and that possibly offers support as well? >>> php.net/ is the official manual. recommended to read it in english so your >>> looking at the latest version (not always the case in other languages). >>> >>> user notes/comments are exactly that - notes, tips, gotcha's, examples >>> related >>> to whatever is documented on a given manual page. occasionally some of the >>> best >>> user notes are merged into the official documentation. >>> >>>> Many thanks in advance for your time. >>>> >> >> >