A good way to specify such refactorings is as a Haskell module. For example:
module PreludePre_7_6 where
import Prelude hiding ( catch )
Or, an example of avoiding the Eq / Show / Num debacle:
module PreludePre_7_4 (module Prelude, Num) where
import Prelude hiding ( Num )
import qualified Prelude as P
instance template (Eq a, Show a) => Num a where
instance P.Num a
(Uses my instance template proposal - though with different keywords -
https://github.com/mgsloan/instance-templates )
Let's say we wanted to rename "catch" to "unsafeCatch"
module PreludePreUnsafeCatch (module Prelude, catch) where
import Prelude hiding (unsafeCatch)
catch = unsafeCatch
Then, an automated refactoring system is "simply" a sourcecode-based
module inliner. Quite a bit of effort, certainly, but it's much
better than coming up with a whole new notation for refactorings.
-Michael
On Thu, Aug 30, 2012 at 6:34 AM, Alexander Bernauer
Hi
I agree that automatic code migration can solve this issue in large parts. The Python folks have done this to mitigate the transition from version 2 to version 3 [1].
On Thu, Aug 30, 2012 at 03:03:05PM +0200, Alexander Kjeldaas wrote:
perl -ni -e 'print unless /import Prelude hiding \(catch\)/' $(git grep 'import Prelude hiding (catch)')
I don't think regular expressions are powerful enough. This example does not match on hiding multiple names, for instance.
But writing proper 'HsModule -> HsModule' functions should be doable.
And when each release comes with a bunch of such functions, packages could be automatically migrated.
Greetings
Alex
[1] http://docs.python.org/library/2to3.html
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