On Sun, Jun 27, 2010 at 9:33 PM, Michael Ekstrand <mich...@elehack.net>wrote:
> On 06/27/2010 10:15 PM, José Romildo Malaquias wrote: > > Is there a symbol type in OCaml, with a constant time comparison > > function? Something like symbols from Scheme and LISP or atoms from > > Prolog. Useful in compiler construction. > > Not directly. As I see it, you have two decent options: > > - Use/write a symbol table which "interns" symbols to integers. The > resulting integers can be compared. > - Use/write a symbol table which interns symbols to unique string > instances, so SymTbl.intern "foo" returns the existing string object if > one already exists, and the string object passed in if it's never been > seen before. The resulting strings can be compared with == rather than > = in constant time. > > Either of these options would be fairly similar to how symbols work > under the hood in a Lisp implementation, I believe. > > Use the Ocaml hash-consing library. http://gallium.inria.fr/ml2006/accepted/5.html http://www.lri.fr/~filliatr/ftp/publis/hash-consing2.pdf Best, -Nick
_______________________________________________ Caml-list mailing list. Subscription management: http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list Archives: http://caml.inria.fr Beginner's list: http://groups.yahoo.com/group/ocaml_beginners Bug reports: http://caml.inria.fr/bin/caml-bugs
