Create flags for my functions?

deep

Hello!

Is it possible to define my own flags for my own functions?

I want to be able to write:

function print_hello_world($som_in_data, FLAG1, FLAG2){
if(FLAG1){ echo "foo"; else if(........... }
}

At the moment i add a variable instead of a fixed name like FLAG1 and FLAG2 but that just doent look very nice 🙂

Roger_Ramjet

The only thing I know of would be an array in session vars: $FLAGS[1] etc. I'm sure someone knows a better way.

deep

Im trying to avoide the $
Look at this example from php.net

preg_match($pattern, $subject, $matches, PREG_OFFSET_CAPTURE, 3);

PREG_OFFSET_CAPTURE isnt using $, im guessing its somehow defined in the function itself, question is how do I define my own flags in my own functions? 🙂

laserlight

By [man]define/maning them?

Roger_Ramjet

Ah! I thought he meant a flag that was set elsewher in the script, not a constant.

deep

Maybe saying "define" was the wrong thing to say.
Im not looking for the define function?

tsinka

Hi,

I think define is the only way. Use define to declare the flags/constants you want to use.

constants are some kind of superglobal so you can use them directly within e.g. functions.

Thomas

deep

Okay, but how will it know that im sending the defined constant as a parameter?

function foo ("hello world", FLAG){}

function foo($string, ???){}

Klaus_Paiva

Just try to get function arguments with func_get_args().

laserlight

but how will it know that im sending the defined constant as a parameter

Consider a function foo() that accepts an argument $arg
If FOO_ADD is set, it adds $arg to itself.
If FOO_MUL is set, it multiplies $arg by itself.
If both are set, it first adds $arg to itself, then multiplies the new result by itself.
If FOO_NEG is set, then the result is negated before being returned.

define("FOO_DEF", 0);
define("FOO_ADD", 1);
define("FOO_MUL", 2);
define("FOO_NEG", 4);

function foo($arg, $flag = FOO_DEF) {
	if ($flag&FOO_ADD) {
		$arg += $arg;
	}
	if ($flag&FOO_MUL) {
		$arg *= $arg;
	}
	if ($flag&FOO_NEG) {
		$arg = -$arg;
	}
	return $arg;
}

The idea here is to use the individual bits in $flag.
As such, the various FOO_* values are set in multiplies of 2 (thereabouts).
So to set both FOO_ADD and FOO_MUL, one would use FOO_ADD|FOO_MUL for the flag.
To do that and negate the final value as well, one would use FOO_ADD|FOO_MUL|FOO_NEG

Also, since a default value for the flag (FOO_DEF) is used as a default argument, one can call foo() using only a single argument - foo() here will just return the argument passed to it untouched.

Roger_Ramjet

All loks a bit like overkill to me. Yes I can see certain situations where it would be really usefull, but not as a general approach to conditional processing.