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Date: Wed, 15 Nov 2006 18:06:42 +0100
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Subject: Re: Feature-Request - Macros
From: phpinternals@thunder-2000.com (Mathias Bank)

Mathias Bank schrieb:
> Hallo,
> 
> you know, that there was often a discussion about a "ifsetor" function. 
> I want to generalize this discussion. If you know LISP, there is a 
> fantastic macro function which allows you to generate own syntax (not a 
> c macro function, which is really bad). It would be fantastic, if php 
> could implement such a macro function. One example (for ifsetor): you 
> could define
> 
> macro ifsetor($param1, $param2) {
>    return "if (isset($param1)) return $param1; else return $param2;
> }
> 
> use: $test = ifsetor($_GET["blubb"],null);
> 
> All you have to do is to not execute the parameters given in the macro 
> parameter list. Instead, you have to evaluate the return statement and 
> then to execute this statement.
> 
> In this way, all discussions about ifsetor (or anything like this) could 
> be avoided.
> 
> The macro function could even be extended to allow new blocks, but then 
> we have to extend the syntax to allow reference to the body. In this 
> way, I always extend the syntax of the parameter data: only variables 
> would be matched.
> 
> macro foreachkey($array as $key, :body $body) {
>   return "foreach ($array as $key=>$__dev0) {
>        $body
>      }";
> }
> 
> know, you can call
> $secondArray = array();
> foreachkey($myArray as $myKey) {
>     $secondArray[] = $myKey;
> }
> 
> this would be extended to
> foreach ($myArray as $myKey=>$__dev0) {
>   $secondArray[] = $myKey;
> }
> 
> and this code will be executed.
> 
> As you see, with this macro functions, it could be achieved any 
> individual syntax. It would be a pleasure, if php could support it. It 
> could shorten a lot of code.
> 
> Mathias

I have recieved a few mails which have shown, that some people 
misunderstood my idea. It seems, that most of you know c/c++ macros. But 
I don't want to implement these macro functionality, because this 
functionality is really poor. Have a look at the macro functionality of 
lisp: 
http://www.gigamonkeys.com/book/macros-standard-control-constructs.html 
and http://www.gigamonkeys.com/book/macros-defining-your-own.html. 
There, it is described, what macros in lisp can do. You will see, that 
such macros cannot be compared with c/c++ macros. But it would be a 
pleasure for php, if such macros would be possible. You should really 
read it, I couldn't believe it until I have realized it at my own.

PHP is a really great language and the syntax is much better than the 
syntax of lisp. But the macros are one big pleasure in lisp. And don't 
mistake lisp macros for c macros. They are much more powerful.

Mathias