New ticket 1274 -- Add a MonadState instance for the Parsec monad

Isaac Dupree isaacdupree at charter.net
Mon Apr 16 07:16:40 EDT 2007


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Malcolm Wallace wrote:
> Just to be absolutely clear:
>   * Parsec.Perm uses existential quantification, which although not
>     Haskell'98 is nevertheless supported by nhc98.
>   * Parsec.Token uses local universal quantification, which is neither
>     Haskell'98 nor supported by nhc98.
> 
> The difference between existential quantification and local universal
> quantification is not widely appreciated or noticed, since both involve
> the 'forall' keyword.

Thank you for the clarification!  That bit of Parsec documentation was
thoroughly unclear about what it meant by using forall. (now, is there
some place that has up-to-date parsec documentation that could be
clearer about that?)

Isaac
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFGI1sXHgcxvIWYTTURAsqHAKC45aZuB/6EiA5ZbUSH1K0yHAi9KACg2gPY
L8eJv3AkeGLCQz1plA4pELo=
=QFSh
-----END PGP SIGNATURE-----


More information about the Libraries mailing list