function name string obtained. how to call function

I personally would use eval() unless you will be calling the functions with parameters that can change, and even then I might give it a try.

http://us2.php.net/manual/en/function.eval.php

$function = 'dothisandthat();'
eval($function);

As with anything that executes I would only use trusted sources to these function, but it appears that you are creating them yourself.

You could actually build the parameters and still use eval.

$paremeter1 = 'code to create parameter 1';
$paremeter2 = 'code to create parameter 2';
$function = 'dothisandthat('.$parameter1.','.$paremeter2.');';
eval($function);

You just retrieve the function name into a variable, say $xyz, and then use it like the function name:

$xyz($parm1, ...);

in your code.

I'm talking to the previously answering experts: Have you ever heard about clean programming?

To the asker: Use is_callable(), and then call_user_func() or call_user_func_array() at your choice.
http://it2.php.net/call_user_func

Anyway I don't like this idea of storing function names inside the database. It's not portable/reusable/maintainable.

ThG, there is nothing unclean about a nice clean neat use of a variable for this.

There is no need to be insulting of others' opinions.

PHP is a very versatile language with many ways of accomplishing similar tasks. Programming is like writing a book, no two writes write the same way.

I can honestly say that I can see the uses of all the suggestions given here, depending on the specific need at the time and I can even say that I've learned something from all the opinions given. It's up to us to provide the opinions and suggestions and for the asker to determine which one best suits their needs and style.

All things available in PHP are meant to be used, if they weren't they would not be in there to begin with.

Hube42: chill out.. I didn't say that your solution is wrong or that you shouldn't have posted! I just said your solution is not clean programming.

You wrote in your comment "code to create parameter 1", which is right but guess what if an unexperienced PHP coder isn't aware of injection? this would be a huge security hole. My solution is less prone than yours to such bugs. See the attached snippet for an exmaple.

yodercm: Your solution is ok actually, it's just a matter of tastes.. i find it unreadable (it looks like a typo :-) ), but of course that's just my opinion.

<?php
 
function my_print($str) {
  print "OUTPUT: $str\n";
}
 
$funcname = "my_print";
$param1 = '"my string"';
$param2 = '"my "); system("pwd"); exit(""';
 
eval('my_print(' . $param1 . ');');
eval('my_print(' . $param2 . ');');
                                              

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Unreadable??  Or just different than you might do.  Even for you, I'm sure a comment about the meaning of $xyz (or of course, better named something like $functionforselecteditem) would be more than enough to address your sensibilities.  Frankly, I think YOUR code is the messiest looking and unreadable of the entire lot.

Just to add a 4th possibility beside
* eval
* functionamevariable
* call_user_func

http://www.php.net/manual/en/language.oop5.reflection.php#language.oop5.reflection.reflectionfunction

$call = new ReflectionFunction($functioname);
$call->invoke($arg1, $arg2, ..)

To the asker:
Sorry about your question getting off track. Do you have any questions about anything that has been posted here? Please let us know so that we can resolve any issues you may be having or questions you have about implementation of any of the choices given.


To ThG:
In my post I did say: "As with anything that executes I would only use trusted sources to these functions..." And I assumed that since the names of functions are what is stored in the database that these functions would be safe. Were not creating code on the fly to be executed from user input or creating a function on the fly from user input, but executing predefined functions.

To yodercm and ThG:
Misunderstandings happen. Let's get back to answering questions and put this behind us.

wow i didnt expect such a response. no problem getting off track. i like to take all opinions and consider them through. i learn much more in that way.
sorry for not commenting earlier need to find some time to experiment with all and will be back soon with more!
thanks all

ok i'll go with angell. its simple and clean and he answered first. Thanks all

one last question if i amy on that.
How can i check whether the function with name $function_name exists? Cause if it doesnt i would like to execute a default one.