CODEWITHSUNDEEP
haskelltypes
Elie Génard
Elie Génard

Reputation: 1683

Wrap Data.Vec types

I'd like to wrap some of the types of Data.Vec in my own types but it doesn't seem to work. For example, I'd like to have my own Vec3 that would be a Vec3F so I did something like this:

Types.h:

module Types
( Vec3(..)
) where

import qualified Data.Vec as V

type Vec3 = V.Vec3 Float

Main.hs:

import Types

vect :: Vec3
vect = Vec3 3 2 4

main = return ()

GHC complains and gives me this error:

Main.hs:4:8: Not in scope: data constructor `Vec3'

Is it because my new type has the same name as a type of Data.Vec despite the fact that I did a qualified import?

If so is there way of doing this without changing the name of my type?

If not, how can I export from my Types module only some types of Data.Vec?

Upvotes: 2

Views: 62

Answers (1)

Jeff Foster
Jeff Foster

Reputation: 44706

Vec3 is not a data constructor, it's a type (in this case, a class). Perhaps you could wrap your own wrapper around the constructor to achieve what you want?

makeVec :: (Double,Double,Double) -> Vec3
makeVec = V.fromXYZ -- TODO some float mangling

Upvotes: 1

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