RE: [PHP] PHP logic - Whats going on here?

Wow, Michael. Nice response. -Ed > -----Original Message----- > From: Michael Sims [mailto:michaels@crye-leike.com] > Sent: Wednesday, August 11, 2004 9:03 AM > To: php-general@lists.php.net > Subject: RE: [PHP] PHP logic - Whats going on here? > > Kim Steinhaug wrote: > [snip] > > For some reason the above results in a blank mail, no $body at all, > > rest is fine. However, if I include a dummy for if all goes well : > > > > if(!$mail->Send()) { > > echo $lang_error['mailer_error'] . "<br>\n"; > > } else { > > // Why do I need this one??? > > } > > > > What I dont understand is why do I need the last else statement? > > You shouldn't. > > > Isnt > > the result of $mail->Send() completed if I only check for > > !$mail->Send()? > > Yes. > > > Maby it would be better to write like this : > > if(!$mail->Send()) { > > echo $lang_error['mailer_error'] . "<br>\n"; > > } else if ($mail->Send()){ > > // Why do I need this one??? > > } > > > > The above would in my belief send two mails, atleast my logic tells > > me that. > > I'm not familiary with phpMailer, or exactly how the Send method words, > but the code > above would end up calling the Send method twice. If the Send method does > in fact > send (as its name suggests) then you probably don't want to call it twice > when you > intend to send the message only once. :) > > [snip] > > Hope someone understand what Im wondering about here, hehe. > > In PHP (and every language that I've ever used...) an if statement's > expression is > evaluated regardless of whether there is an else portion, or an elseif, > etc. For > example, suppose we have a function foo() that is evaluated primarily for > its side > effects, but may return either true or false to indicate if the function > was > successful. This: > > if (foo()) { > print "foo() was successful!\n"; > } > > is functionally equivalent to this: > > if (foo()) { > print "foo() was successful!\n"; > } else { > > } > > The null else clause should have no effect whatsoever on the execution of > the > script. In fact, the following code snippets are all functionally > identical: > > //Version one > foo(); > > //Version two > if (foo()) { > > } > > //Version three > if (!foo()) { > > } else { > > } > > In all three cases foo() is evaluated just once. > > Something else you should be aware of: When the expression in the if > statement is a > compound expression (it contains multiple expressions), then the PHP > parser uses > "lazy" or "short-circuit" evaluation. This means that the parser only > evaluates the > portions of the expression that are necessary to calculate the result of > the entire > expression. An example: > > if (foo() && bar()) { > //Do stuff > } > > In the above example, foo() is evaluated first. If foo() returns false, > bar() is > not evaluated at all. The reason is that no matter what bar()'s return > value is, > the entire expression can only be false. Since the parser has already > determined > the final result, it has no need to evaluate any further terms. > Similarly: > > if (foo() || bar()) { > //Do stuff > } > > In this example, bar() will not be evaluated if foo() returns true, but > will be if > foo() returns false. These are obviously simple examples, but basically > the parser > only evaluates the terms that are necessary and doesn't go any further. > This can be > used as a type of flow control to have certain functions/methods called > only if > another returned true or false. For example, the following two code > snippets are > functionally identical: > > //Version one > if (foo()) { > bar(); > } > > //Version two > if (foo() && bar()) { > > } > > As far as your specific problem, I suspect that there are factors at play > that you > are not aware of. Either you have run across a bug in the PHP parser > itself > (unlikely), or you are inadvertently making other changes when you add the > else > clause. I would suggest using basic debugging techniques to echo/print > the contents > of the body string at various points to see what it contains. You may > need to drill > down into the actual source code for the Send() method to see what it > things the > body string is. If something is happening to this value this approach > should reveal > where it's occuring. > > HTH... > > -- > PHP General Mailing List (http://www.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php