Sorry, I sent the email to the wrong place and messed up the code
(it's early :)). Take two:
transform = everywhere (mkT transform')
where transform = (\Term a->Flattened a)
`extT` (Contstant a->Flattened a)
On 12/19/06, Vyacheslav Akhmechet <[EMAIL PROTECTED]> wrote:
That should be pretty simple. This code probably won't work, but you
can use it as an example to look into this further.
transform everywhere = (mkT transform')
where transform = (\Term a->Flattened a)
`extT` (Contstant a->Flattened a)
Something like this should work. Look into the docs for more info.
On 12/19/06, Grote Collective <[EMAIL PROTECTED]> wrote:
> Hello all,
>
> I have two datatypes, both representing the same language. However, one is a
> "flattened" version of the other. For instance:
>
> data Flattened =
> Const Flattened
> | Sum Flattened Flattened
> | ...
> | IntConst Int
> | RealConst Float
> | BoolConst Bool
> | Void
>
> ----
>
> data Term =
> Const Constant
> | Sum Term Term
> | ...
>
> data Constant =
> IntConst Int
> | RealConst Float
> | BoolConst Bool
> | Void
>
>
> Now I want to create functions to convert between these two datatypes. This
> is easy to do but *very* tedious in its most naive approach. However, I
> think I can use Data.Generics to make a simple implementation of both
> functions. The question is: can I? I think that this conversion is a simple
> fold over the structure, changing merely the constructor name (the qualified
> name, because the unqualified name is the same), but I cannot seem to
> understand from the documentation how to do this...
>
> Thanks in advance,
> Mark Smith
>
> _______________________________________________
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> [email protected]
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
>
>
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