[Template-haskell] Lift instances of the AST-related types

[Alfonso Acosta]

This recent haskell-cafe thread[1] provides a way to implicity give
support for automatic derivation of Lift in GHC.

Since Data can be derived automatically and there's a way to lift any
"Data a => a" it's like having
automatic derivation for lift.

It's not a substitute of Ian's package (the instace Data a => Lift a
is illegal), but it complements it.

What do you think about including a function like "liftData :: Data a
=> a -> ExpQ" in the library?


On 11/2/07, Alfonso Acosta <alfonso.acosta at gmail.com> wrote:
> On 11/2/07, Simon Peyton-Jones <simonpj at microsoft.com> wrote:
> > It'd be good to check that the Haddock docs for TH.Lift are in good shape.
>
> Well, right now they are inexistent but the library is tiny, that
> shouldn't be a problem.
>
> > I'll leave this up to you two to finalise.
>
> Let's see what Ian thinks
>
> > (In fact it'd be great if you could improve the Haddock docs for the other TH modules.  They are currently laughably bad.  And you are clearly an expert!)
>
> I cannot agree more, when I began to use TH I was forced (and I keep
> doing it) to look at the source comments to check what the AST-types
> meant.
>
> I cannot promess anything for the short-term, but I'll try to send a
> documentation patch at some point.
>