Hi, Ian, you can use qualified imports to manage that. Then you can write
module Test where
import qualified Aaa as QualifiedA ( Foo )
import Bbb ( Foo )
Below you can use barFoo by prepending QualifiedA e.g.
fooA = QualifiedA.Foo "Hi, I'm from A" fooB = Foo "I belong to B"
More information is available at http://www.haskell.org/haskellwiki/Import Regards, Nikita On 29/04/13 12:28, Ian Knopke wrote:
Hi everyone,
I have two modules that share a common data type in their respective data structures:
package Aaa where
newtype Foo = Foo String
data Bar = Bar { barFoo :: [Foo] } deriving (Show, Eq) ...
package Bbb where
newtype Foo = Foo String
data Quux = Quux { quuxFoo :: [Foo] } deriving (Show, Eq) ...
Both modules require the Foo newtype defined. However, in all other respects they are separate modules that can be used independently.
Defining the newtype Foo twice, as above, throws a compilation error (ambigious reference). Importing one module inside another breaks independence. I've been including newtype Foo in a Common.hs module that is included in both, as I would in C or C++. This sort of thing can easily get more complicated as the program grows however.
I was wondering if the Haskell community has a better solution to this that I've overlooked.
Ian Knopke
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