Jon Harrop wrote:

> Basically, you memoize strings:
> 
> # let symbol =
>     let m = Hashtbl.create 1 in
>     fun string ->
>       try Hashtbl.find m string with Not_found ->
>       Hashtbl.add m string string;
>       string;;
> val symbol : '_a -> '_a = <fun>

...which is, of course, just a consequence of the OCaml drawback that
there is no proper "symbol" data type (which actually would be useful,
in particular in conjunction with proper EQ hash tables)...

By the way, the Perl interpreter does the same thing with
script-constant strings, also using this to provide
"effective almost-symbols".

-- 
best regards,
Thomas Fischbacher
tf@functionality.de