Actually Todd, ... > There is no way to call a function > before doing the work in the argument list. If I call f(1+2), > I can be sure the computation to get 3 will be performed > _before_ calling f. The issue with f($p=array()) is that > "$p=array()" is an r-value.
...that is theoretically very possible, and it's something called "lazy evaluation": http://en.wikipedia.org/wiki/Lazy_evaluation - Ron "Todd Ruth" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > It looks like > http://www.php.net/manual/en/language.operators.assignment.php > could use a bit of updating. A paragraph about php 5 or a > link to the semantics changes for php 5 would help newbies. > The text about php4 says there is copy on assignment, which > implies a performance hit for using = instead of =&, but I > believe "copy on change" is more accurate. It wouldn't hurt > to explicitly say that "=" is generally better than "=&" > (unless you really need an alias). A user comment has been > there unchallenged for over 2 years saying you can pass an > assignment as a reference to a function, so it isn't surprising > that someone considered the 5.1.1 to 5.1.2 change an issue. > (Not that a user comment should bind the php devs, but when > the comment goes unchallenged, it can lead to false impressions.) > Perhaps some text explaining the assignment returns an r-value > would be helpful. (If people understand "($x = 1) = 2;" > shouldn't work, they might understand that passing "$x=1" to > a function by reference shouldn't affect $x. (or should > "($x = 1) = 2;" work and 5.1.2 had a real bug?)) > > I have to say the documentation for php is completely awesome > and is a major factor in our company using the language. I > just point out the above to help; it isn't a complaint. > > BTW, I disagree with the post below that indicates the issue is > the order of calling. There is no way to call a function > before doing the work in the argument list. If I call f(1+2), > I can be sure the computation to get 3 will be performed > _before_ calling f. The issue with f($p=array()) is that > "$p=array()" is an r-value. > > - Todd > > On Mon, 2006-07-24 at 19:16 +0200, Johannes Schlueter wrote: > > Hi, > > > > On Monday 24 July 2006 17:52, Rishad Omar wrote: > > > getArray($p = array()); > > > > Here you are relying on undefined behavior. It is not defined wether $p = > > array() or the function call getarray($p) should be executed first so the > > order might always change. > > > > You should always use the two lines > > $p = array(); > > getArray($p); > > to be safe. > > > > johannes > > > -- > Todd Ruth <[EMAIL PROTECTED]> -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
