Re: [Template-haskell] example of derive using Template Haskell?

11 Jan 2005


      On Tue, 11 Jan 2005 12:35:40 -0500 (Eastern Standard Time), S.
Alexander Jacobson  wrote:
...
I have {-# OPTIONS -fglasgow-exts #-} at the top
of both modules.  Does that not imply -fth?
If you use GHC 6.2.2 then yes. This has changed in GHC 6.3.
...
I do realize that my example is not valid Haskell
code.  I am looking for an example of valid
Haskell code that allows me to derive a class.
Checkout 'InstanceD' from the data structure 'Dec' and 'reifyDecl'.
...
Or even just an example of actualy usage of
[d|...] that works with GHC 6.2.2!
SO far I haven't been able to find one.
I mailed you an example not so long ago (-:

These two splices are equivalent and work with GHC 6.2.2:
$([d| baz = "Hello Template Haskell" |])
$(do fn <- valD (varP "baz") (normalB (litE (stringL "Hello Template
Haskell"))) []
     return [fn])

-- 
Friendly,
  Lemmih