foreach in $loc do checkit;
if $target's link > 0 then islinked else noexit;
##checkit:
if $for_id's class like exit then useit else fail;
##useit:
var $target to $for_id;
##islinked:
set $target's link to $loc;
set $target's qty to 1;
say 'change',"[$actor] fixes the exit in this location";
look $loc;

##noexit:
say 'look',"[$actor] looks around for an exit but could not find one";
look $loc;