[Haskell-cafe] IO in lists

ajb at spamcop.net ajb at spamcop.net
Tue Jan 16 20:20:07 EST 2007


G'day all.

On Tue, Jan 16, 2007 at 14:06:08 +0200, Yitzchak Gale wrote:

> >But the list monad [] is not a transformer, so you can't lift in it,
> >even if the contained type happens also to be a monad.

Quoting Magnus Therning <magnus at therning.org>:

> Yeah, I had some vague thought of that being a problem, which lead me to
> ListT.

ListT is also not a transformer.  See here for details:

    http://www.haskell.org/hawiki/ListTDoneRight

Cheers,
Andrew Bromage


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