haskell load module in list

Question

Hey haskellers and haskellettes, is it possible to load a module functions in a list. in my concrete case i have a list of functions all checked with or

checkRules :: [Nucleotide] -> Bool
checkRules nucs = or $ map ($ nucs) [checkRule1, checkRule2]

i do import checkRule1 and checkRule2 from a seperate module - i don't know if i will need more of them in the future.

i'd like to have the same functionality look something like

-- import all functions from Rules as rules where
-- :t rules ~~> [([Nucleotide] -> Bool)]

checkRules :: [Nucleotide] -> Bool
checkRules nucs = or $ map ($ nucs) rules

the program sorts Pseudo Nucleotide Sequences in viable and nonviable squences according to given rules. thanks in advance ε/2

Addendum: So do i think right - i need:

genList :: File -> TypeSignature -> [TypeSignature]
chckfun :: (a->b) -> TypeSignature -> Bool

at compile time. but i can't generate a list of all functions in the module - as they most probably will have not the same type signature and hence not all fit in one list. so i cannot filter given list with chckfun.

In order to do this i either want to check the written type signatures in the source file (?) or the inferenced types given by the compiler(?).
another problem that comes to my mind is: not every function written in the source file might get exported ?
Is this a problem a haskell beginner should try to solve after 5 months of learning - my brain is shaped like a klein's bottle after all this "compile time thinking".

Not really. You could perhaps generate the import list programmatically from Template Haskell. — Don Stewart, Jun 12 '11 at 16:44
hmm - i had a look at Template Haskell and was quite overwhelmed - could you give me some hints or keywords to look for. — epsilonhalbe, Jun 12 '11 at 22:41

score 6 · Accepted Answer · answered Jun 13 '11 at 01:55

There is a nice package on Hackage just for this: language-haskell-extract. In particular, the Template Haskell function functionExtractor takes a regular expression and returns a list of the matching top level bindings as (name, value) pairs. As long as they all have matching types, you're good to go.

{-# LANGUAGE TemplateHaskell #-}
import Language.Haskell.Extract

myFoo = "Hello"
myBar = "World"

allMyStuff = $(functionExtractor "^my")

main = print allMyStuff

Output:

[("myFoo", "Hello"), ("myBar", "World")]

haskell load module in list

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