[Haskell-beginners] instance

[Ut Primum]

Hi,

data TisanInteger = Tisan Integer
instance Eq (*Tisan Integer*) where (Tisan v) == (Tisan v') = v == v'

I think the part in red is the error: you should write *TisanInteger*
instead (with no space between Tisan and Integer):
This is because there you should put the name of the data, not its
definition.

Best,

Ut


Il giorno mer 22 apr 2020 alle ore 20:11 Alexander Chen <
alexander at chenjia.nl> ha scritto:

> Hi,
>
>
> *data TisanInteger = Tisan Integer*
>
> *instance Eq (Tisan Integer) where (Tisan v) == (Tisan v') = v == v'*
>
> *prelude>*
> *Instance_testen.hs:7:14: error:*
> *    Not in scope: type constructor or class ‘Tisan’*
> *    A data constructor of that name is in scope; did you mean DataKinds?*
> *  |*
> *7 | instance Eq (Tisan Integer) where (Tisan v) == (Tisan v') = v == v'
>  |              ^^^^^*
> *[1 of 1] Compiling Main             ( Instance_testen.hs, interpreted )*
> *Failed, no modules loaded.*
>
>
>
> what am i doing wrong?
>
> best,
>
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