On Mon, Jul 1, 2013 at 5:42 PM, TP <paratribulati...@free.fr> wrote:
> So what is the difference between lift and [||]?
> Although I feel stupid, I cannot lie and claim I have understood.
Hi TP,
Sometimes [| |] does need to call lift. If for some reason the
original lift wasn't exported, you could define:
myLift x = [| x |]
But if you have enough $( ) splices to balance out the [| |], there is
no lift involved:
myId1 x = $( [| x |] )
myId2 x = [| $(x) |]
I think your first example is supposed to do:
*Pr> let x = 5 in $(pr 'x)
x = 5
That's possible if you had defined pr as:
pr n = [| putStrLn $ $(lift (nameBase n)) ++ " = " ++ show $(varE n) |]
If there were no [| |] quotes, but still the ' syntax for getting a
Name, it would still be possible to define pr:
pr2 n
= varE 'putStrLn `appE`
(infixE (Just (lift (nameBase n))) (varE '(++))
(Just
(infixE (Just (lift " = ")) (varE '(++))
(Just (appE (varE 'show) (varE n))))))
--
Adam
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