Re: [Haskell-beginners] another type problem

Try fromMaybe [1]. Examples Prelude Data.Maybe> fromMaybe [] (Just [1,2,3]) [1,2,3] Prelude Data.Maybe> fromMaybe [1,2,3] Nothing [1,2,3] [1]: https://hackage.haskell.org/package/base-4.8.0.0/docs/Data-Maybe.html#v:from... On Tue, May 12, 2015 at 5:28 PM Roelof Wobben wrote:

Oke,

And how do I do this. Haskell is a difficult one to learn,

Roelof

Alexey Shmalko schreef op 12-5-2015 om 16:24:

Before cons'ing the result of init', you should check whether it's Just or Nothing. What you're doing now is something along the line with 5 : Just 3 -- this won't typecheck.

On Tue, May 12, 2015 at 5:22 PM Roelof Wobben wrote:

...

Brandon Allbery schreef op 12-5-2015 om 16:16:

On Tue, May 12, 2015 at 10:11 AM, Roelof Wobben wrote:

...

I do not understand what you are saying to me.

I know that init produces a Maybe [a] . That is why I did put a Just before it.

You are invoking it again though, and using its result as if it produces [a] instead of Maybe [a].

-- brandon s allbery kf8nh sine nomine associates allbery.b@gmail.com ballbery@sinenomine.net unix, openafs, kerberos, infrastructure, xmonad http://sinenomine.net

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What is then the right way to do. I still do not understand what you are trying to make clear to me.

Roelof

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