Non-exhaustive patterns in function error

Galaxy Being

25 Feb 2021 25 Feb '21

6:23 p.m.

I have this intersect1 :: ([a],[a]) -> [a] intersect1 (s,[]) = [] interesct1 (s,t:ts) | elem t s = t : intersect1 (s,ts) | otherwise = intersect1 (s,ts) and when I try this intersect1 ([1,2],[1,2,3]) I get the error Non-exhaustive patterns in function intersect1 Not sure what's wrong with this. LB

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Francesco Ariis

25 Feb 25 Feb

6:45 p.m.

Il 25 febbraio 2021 alle 17:23 Galaxy Being ha scritto:

...

I have this

intersect1 :: ([a],[a]) -> [a] intersect1 (s,[]) = [] interesct1 (s,t:ts) | elem t s = t : intersect1 (s,ts) | otherwise = intersect1 (s,ts)

and when I try this

intersect1 ([1,2],[1,2,3])

I get the error

Non-exhaustive patterns in function intersect1

Not sure what's wrong with this.

Pattern (_,[]) is not matched!

Bob Ippolito

6:52 p.m.

It's the typo. Note that you'll also need an Eq a typeclass constraint for this type signature to be correct (which is the next error you'd get) -- underscores for emphasis inter_se_ct1 inter_es_ct1 On Thu, Feb 25, 2021 at 3:24 PM Galaxy Being wrote:

...

I have this

intersect1 :: ([a],[a]) -> [a] intersect1 (s,[]) = [] interesct1 (s,t:ts) | elem t s = t : intersect1 (s,ts) | otherwise = intersect1 (s,ts)

and when I try this

intersect1 ([1,2],[1,2,3])

I get the error

Non-exhaustive patterns in function intersect1

Not sure what's wrong with this.

LB

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Galaxy Being

9 p.m.

How embarrassing... intersect1 :: (Eq a) => ([a],[a]) -> [a] On Thu, Feb 25, 2021 at 5:53 PM Bob Ippolito wrote:

...

It's the typo. Note that you'll also need an Eq a typeclass constraint for this type signature to be correct (which is the next error you'd get)

-- underscores for emphasis inter_se_ct1 inter_es_ct1

On Thu, Feb 25, 2021 at 3:24 PM Galaxy Being wrote:

...
I have this

intersect1 :: ([a],[a]) -> [a] intersect1 (s,[]) = [] interesct1 (s,t:ts) | elem t s = t : intersect1 (s,ts) | otherwise = intersect1 (s,ts)

and when I try this

intersect1 ([1,2],[1,2,3])

I get the error

Non-exhaustive patterns in function intersect1

Not sure what's wrong with this.

LB

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Brody Berg

10:51 p.m.

Don’t worry about it. We’ve all been there. On Thu, Feb 25, 2021 at 18:01 Galaxy Being wrote:

...

How embarrassing...

intersect1 :: (Eq a) => ([a],[a]) -> [a]

On Thu, Feb 25, 2021 at 5:53 PM Bob Ippolito wrote:

...
It's the typo. Note that you'll also need an Eq a typeclass constraint for this type signature to be correct (which is the next error you'd get)

-- underscores for emphasis inter_se_ct1 inter_es_ct1

On Thu, Feb 25, 2021 at 3:24 PM Galaxy Being wrote:

...
I have this

intersect1 :: ([a],[a]) -> [a] intersect1 (s,[]) = [] interesct1 (s,t:ts) | elem t s = t : intersect1 (s,ts) | otherwise = intersect1 (s,ts)

and when I try this

intersect1 ([1,2],[1,2,3])

I get the error

Non-exhaustive patterns in function intersect1

Not sure what's wrong with this.

LB

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_______________________________________________ Beginners mailing list Beginners@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

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Bob Ippolito
Brody Berg
Francesco Ariis
Galaxy Being