eval and functions

RobC

I have an html file that for simplicity has:

When i run my php file, i str_replace  with somefunction(), and then i eval the string.

But this does not appear to work, I have also tried replacing  with <?php somefunction() ?>, but that does not work either.

Is what I am trying to achieve possible?

Thanks,

PHPGuru2

How are you exactly running your PHP file with this HTML file??

RobC

Ok, my parsing basically looks like this:

	$layoutpage = implode('', file("layout.html"));

$layoutpage = str_replace( "!--%LeftBlock%-->",
		"<?php left(); ?>", $layoutpage);

$layoutpage = addslashes( $layoutpage );

$layoutpage = "\$result=\"".$layoutpage."\";";

eval($layoutpage);
    echo($result);

and my html looks like:

<table width=$width height=$height border=0 valign="top">
<tbody>
	<tr>
		<td style="vertical-align: top;" rowspan="1" colspan="3"><!--%TagToReplace%--></td>
	</tr>
.
.
.

and i get this as a result:

<table width=955 height=640 border=0 valign="top">
<tbody>

<tr>
	<td style="vertical-align: top;" rowspan="1" colspan="3"><?php left(); ?></td>
</tr>

.. Hope this makes sense.

seby

this is easier:


$some_function = left();

eval('echo("' . implode('', file('layout.html'))  . '");');

then use $some_function in your template file and it will parse it as php

dave420

Rob - you've got a great idea but there are much better ways of doing it. I've yet to see a legitimate use of eval() where it isn't being used as a quick hack. I'm not being rude, but I've been coding PHP professionally for ages and I've never had to use it.

If I was doing what you were doing, I would look for your special tags using regular expressions, then call the associated functions and replace the output back into the string (possibly using preg_replace_callback). That way, you don't have to eval anything.

Weedpacket

Originally posted by dave420
Rob - you've got a great idea but there are much better ways of doing it. I've yet to see a legitimate use of eval() where it isn't being used as a quick hack. I'm not being rude, but I've been coding PHP professionally for ages and I've never had to use it.

I've used it in a CMS compiler ... during a CMS's development everything would come out of a database - code included. But that's probably getting into übergeek territory.

(possibly using preg_replace_callback)

Or the /e modifier - but that's just eval again 🙂.

dave420

I've never ever seen a good use for eval in 5 years of coding PHP. All I've ever seen it used for is quick hacks, or to cover someone's ass when they can't code for toffee. It's a terrible way to code, as it means the language is hard-coded in the language, which (as you can imagine) raises all sorts of issues with regard to upgradability and futureproofing.

Keeping code in a database? I've seen ubergeeker 😉

RobC

Originally posted by dave420
If I was doing what you were doing, I would look for your special tags using regular expressions, then call the associated functions and replace the output back into the string (possibly using preg_replace_callback). That way, you don't have to eval anything. [/B]

Thanks for that idea, the number of things I had to replace would never change, that is why i picked eval, but yes your way is much better.

Looks like I still have heaps to learn. 🙂

So you think that using callbacks is the way? That makes sense, I shall do it that way then.

Thanks guys for all your help.

Weedpacket

Originally posted by dave420
Keeping code in a database? I've seen ubergeeker 😉

Oh, among other things it made upgrading easier: update the db'd library code and recompile the world. Bang - everyone's upgraded.