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Today's Topics:
1. Re: Stack implementation (Imants Cekusins)
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Message: 1
Date: Sat, 10 Sep 2016 23:47:43 +0200
From: Imants Cekusins <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: Re: [Haskell-beginners] Stack implementation
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<CAP1qinZBgXYgMGeo974kqTSk4hVz76+=0-qckufxzfbzwqk...@mail.gmail.com>
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Hello Uneeb,
instances of class Stack are defined for *s*. empty's *return* type is *s a*
*empty* does not take any arguments. GHCi is confused about *empty*'s
*return* type.
option 1:
try adding *return* type at prompt e.g.:
empty::ListStack Int
instead of just empty
option 2:
add *a* as Stack class parameter i.e.:
class Stack s *a* where
...
then if you define only 1 instance, interactive will probably assume that
you expect *empty* to return that (the only one defined) type
see if this works
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