Proposal: Add Text.Read.maybeRead :: Read a => String -> Maybe a
john at repetae.net
Thu Feb 7 22:48:35 EST 2008
On Thu, Feb 07, 2008 at 10:46:48AM -0800, Don Stewart wrote:
> This function is typically defined once per project. So its
> about time this safe variant of 'read' made it into the base.
> maybeRead :: Read a => String -> Maybe a
> maybeRead s = case reads s of
> [(x, "")] -> Just x
> _ -> Nothing
> Consideration period: 1 week.
May I suggest 'readM'?
It is just the obvious generalization of the 'readIO' that is in the
Prelude, that it isn't generalized is a bug in the prelude IMHO. (and it
is signifigantly more useful)
> readM :: (Monad m,Read a) => String -> m a
> readM s = case reads s of
> [(x, "")] -> return x
> _ -> fail "readM: no parse"
John Meacham - ⑆repetae.net⑆john⑈
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