[Haskell-cafe] Re: catching fails on read

Don Stewart writes:

jbergeron:

...

I'm new to Haskell and have a stupid question.

How can a catch a parsing error on a read? Something like

let s = "e" in read s :: Int

I've been searching for a trick and couldn't find one. I want to enter commands directly from the keyboard and don't want the program to abort if

I

...

do a typing error.

maybeRead :: Read a => String -> Maybe a maybeRead s = case reads s of [(x, rest)] | all isSpace rest -> Just x _ -> Nothing

There's an open ticket to add this to the base library.

So reads (or readsPrec) is the "parser" equivalent to read. Should have catched that, sorry. Thanks for your time. Jacques