global - PHP function written in 5.5 throws error when upgraded to 7.0 -

here function worked prior upgrading 7.0

function set_session_vars() { $nb_args=func_num_args(); $arg_list=func_get_args(); for($i=0;$i<$nb_args;$i++) {     global $$arg_list[$i];     $_session[$arg_list[$i]] = $$arg_list[$i]; } 

}

now causer error says:

parse error: syntax error, unexpected '[', expecting ',' or ';' in /home/mvyc1956/public_html/members/includes/functions.php on line 322 

i believe related non backward compatable changes global , use of $$ , arrays, php not enough figure out.

is there familiar why line :

global $$arg_list[$i]; 

which line 322 being reported cause of error, failing now, , recommend change code in order have work php 7?

i did googling , found this page again, im not understanding needs changed.

thanks

says syntax error of code in function no longer valid, take php 7 expert see it.

update removed word global above code , app "seems" working fine ask:

does know specifically, why global non compatibility issue? , fix of removing solid 1 or there better practice or removal come haunt me?

backward incompatible changes:

global accepts simple variables

variable variables can no longer used global keyword. curly brace syntax can used emulate previous behaviour if required:

// valid in php 5 only. global $$foo->bar;  // valid in php 5 , 7. global ${$foo->bar}; 

so in case should become:

global ${$arg_list[$i]};