在PHP中使用变量NAME作为值

Question

Not sure how to ask this without rambling about preprocessors in C, but I will try:

Is there a way in PHP, to use the name of a variable as a string or value.

Such that instead of calling function like this,

$somevar = 'whatever';

fun('somevar', $somevar);

you can call it like this:

fun(<magic:$somevar>, $somevar);

or even, dare I say it, like this :

fun($somevar);

and the fun() would itself deduce both the value ('whatever'), and the name ('somevar') of the variable. (In C, it could be done with a preprocessor #define.)

_{"magic" above is of course a place holder for the magic syntax in PHP I am looking for which will help me do this. I guess it could be made somehow with eval()? But people keep telling me not to use eval.}

Someone hinted that introspection might somehow do the trick. Any leads there would be welcome.

Answer 1

Try this

function var_name(&$var, $scope=0)
{
    $old = $var;
    if (($key = array_search($var = 'unique'.rand().'value', !$scope ? $GLOBALS : $scope)) && $var = $old) return $key;  
}

Answer 2

http://php.net/manual/en/language.variables.variable.php

The probably explain it better than I can, I think this is what you're looking for?

Alright, before you call the function do the following:

$var= "variableName";
$$var = "variableValue";
fun($var);

Now within the function definition for fun:

function fun($parameter)
{
    global $$parameter;
    echo $parameter; //echos the variableName
    echo $$parameter; //echos the variableValue
}

Answer 3

No. PHP's scoping rules prevent you from doing that. The only way would be through a pre processor (as you are aware) or by introspecting the code, which would be kind of the same thing. PHP has a built-in tokenizer, that you can use to parse a file with. You can use debug_backtrace to find out which files to parse through. It's going to be a really messy and inefficient thing to do though, so you would probably be better off rethinking what you're doing.