bash: call function with variables vs function with arguments

Question

Lets take for example next function:

version 1 - with variables:

 backup () {
 for arname in `arname_f`
 do
   slapcat -b "$setnames" -l "$bkdir"/"$ardate"_"$arname".ldif || exit 1
 done
 }

and run it just with code:

 backup;

version 2 - with positional arguments:

 backup () {
 for arname in `arname_f`
 do
   slapcat -b "$1" -l "$2"/"$3"_"$4".ldif || exit 1
 done
 }

and let's run with such code:

 backup $setnames $bkdir $ardate $arname;

Is there any difference in this slants?

Answer 1

The question has nothing to do with Bash as such.

The #1 is the example of "Spaghetti" coding style (global variables) hated by most professionals and simply sane people. It will eventually cause a major problem when someone somewhere changes the parameter and the function starts misbehaving, and you won't have a clue of who/what has changed what where.

The #2 is close to how I would do it. Though, of cause, there may well be a valid reason to prefer #1, it depends.