While FTW! I just wondered whether it could be simplified because I get a bit tired of typing out my own belt and braces version of it:

  { # code that generates one item/filename per line of output }  | { while read ITEM; do # do something with "$ITEM"; done; }

So I just tried this and it seems to work for a trivial case although you need 1 escape:

  enum() {
    local source=$1; shift; local action=$1; shift  
    { eval "$source" ; } | { while read ITEM; do eval "$action"; done; }
  }

  $ enum "find /tmp" "echo found: \$ITEM"

  found: /tmp/.XIM-unix
  found: /tmp/.ICE-unix