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To: Cristiano Duarte <cunha17@uol.com.br>
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Date: Mon, 18 Aug 2003 21:13:33 +0200
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Subject: Re: [PHP-DEV] userland macros
From: thekid@thekid.de (Timm Friebe)

On Mon, 2003-08-18 at 20:56, Cristiano Duarte wrote:
> Is possible to implement userland macros in a PHP extension or it can 
> only be implemented in the core?
A "userland" solution could be to use cc -E on your .php files.

> I know that macros is a preprocessor task and I think PHP has no 
> preprocessor (does it?).
It doesn't.

> So it's possible to implement a preprocessor ?
It's possible, of course, but PHP needs to compile fast as (without any 
accelerator products whatsoever) this is what happens on each request to
a script. A preprocessor takes up more time and IMHO only makes sense in
compiled languages (in the original sense of "compiled":)).

> An example (or something like that):
[...example...]

thekid@friebes:~ > cat prep.phpc 
<?
#define DEFAULT_VALUE(check_value, default_value) \
  (isset(check_value) ? check_value : default_value)

$a = DEFAULT_VALUE($my_array['some_index'], true);
?>
thekid@friebes:~ > cc -P -C -E -x c prep.phpc 
<?


$a = (isset( $my_array['some_index'] ) ?  $my_array['some_index']  :  
true ) ;
?>

Notes on command line arguments passed to cc:

-E   execute preprocessor only
-P   do not generate #<line> comments
-x c Set language to "C".
-C   leave comments intact

You might also want to do a grep -v '^$' to get rid of some of the
whitespace leftovers by the preprocessor.

- Timm