var string tag_name = ""; foreach var string c($tag_from_url) { $tag_name = $tag_name + (($c == "+") ? " " : $c);}
Other options:
no subject
Replacing "+" with " " is a bit more complicated, and would (I think) involve going through the entire string character by character and then replacing the "+" if you see it.
Hmm. Maybe not as complicated as I thought:
var string tag_name = "";
foreach var string c($tag_from_url) { $tag_name = $tag_name + (($c == "+") ? " " : $c);}