[Resolved] Why this doesn't work?

bike5

I am sending a variable to a function and it only works if I hard code it. But it doesn't work when I do it the way I want to.

$item = $REQUEST['buy'] . "Info" . '("' . $REQUEST['type'] . '")';echo $item;//This == " BootsInfo("Alpine")
"

That is what doesn't work. It gives me back a "B"??
I also tried:
$item = $REQUEST['buy'] . Info($REQUEST['type']);
which gives me back Call to undefined function: info()
Here is what works:

$item = BootsInfo("Alpine");echo $item;//This == " BootsInfo("Alpine")
"
But this works and I get back what I want.

They look the same to me, where am I missing?

bubblenut

da da da DAA!!! eval() to the rescue. Here he comes to save the day!!!

<?php
$item=eval($_REQUES['buy']."Info(\"".$_REQUEST['type']."\");");
echo($item);
?>

I never like this type of design myself. It just feels if you need to do that there is a better way of designing it. Prehapse look into OO and inheritance?
HTH
Bubble

Weedpacket

eval() is all right (but messier), some more planning would a very good idea (self-modifying code is so 1960s 🙂), but

$item = call_user_func($_REQUEST['buy'].'Info', $_REQUEST['type']);

// or

$function = $_REQUEST['buy'].'Info';
$item = $function($_REQUEST['type']);

would work as well.

dave420

The best way would be to have a function you pass the "BootsInfo" to as an argument, along with the "Alpine" bit. That way, the function can then determine the correct course of action, as opposed to using language constructs to do your dirty work 😉

When I say this, I'm not having a go at anyone (or anyone's ability or style), but there is always a better solution than eval(). always. Eval is a quick hack, at best. Better function structure or OOP negates the need for it. When I was learning PHP I found that if I was ever tempted to use eval(), I'd look further at my code until I could find a way to not use it.

bike5

Thanks for the help guys, my little "PHP for the world wide web" book doesn't cover any of this stuff, I really need to get a more advanced book.

bubblenut

While looking for cheap PHP books on ebay I found this not quite what you're looking for though I'm guessing.
I found Wrox Professional PHP very usefull but I'm not sure if it's around anymore. O'reilly's are my favourites at the mo (learning java, regular expressions), they're very no nonsense, straight to the point books but may be a little too quick for a beginer.
HTH
Bubble

bike5

Hmmm that php item on ebay is very tempting. I must make my bid!...lol