core comparison for fun.

3 Feb 2006


      Just for larks, here is a side by side of the various compilers core for
the example on that page:

Haskell:
...
module FibMain where
main xs = pam daeh xs
daeh (x:xs) = x
pam f [] = []
pam f (x:xs) = f x : pam f xs
Yhc:
...
FibMain.pam v220 v221 =
    case v221 of
        Prelude.[] -> (Prelude.[])
        Prelude.: v222 v223 ->
            (Prelude.: (YHC.Internal._apply1 v220 v222) (FibMain.pam v220 v223))
FibMain.daeh v224 =
    case v224 of
         Prelude.: v225 v226 -> v225
         _ -> (Prelude.error (LAMBDA228))
LAMBDA228 =
    (prim_STRING "FibMain: Pattern match failure in function at 7:1-7:15.")
FibMain.main v227 = (FibMain.pam FibMain.daeh v227)
Jhc:  (unicodey!)
...
FibMain.main = ΛFibMain.v22.λFibMain.1_xs∷[[FibMain.v22]].(let
        x9282∷[FibMain.v22] → FibMain.v22 = λx9284∷[FibMain.v22].(case x9284 of
                (x9286∷FibMain.v22):(x9288∷[FibMain.v22]) → x9286;
                Prelude.[] →
                    <⊥:test/fibmain.hs:5:13: Unmatched pattern∷FibMain.v22>;);
        x9280∷⋆ = [FibMain.v22];
        in FibMain.pam x9280 FibMain.v22 x9282 FibMain.1_xs)
FibMain.pam = ΛFibMain.v5.ΛFibMain.v10.λx9296∷FibMain.v5 → FibMain.v10.λx9298∷[FibMain.v5].(case x9298 of
        (x9300∷FibMain.v5):(x9302∷[FibMain.v5]) → let x9316∷[FibMain.v10] =
                                                          FibMain.pam FibMain.v5 FibMain.v10 x9296 x9302;
                                                      x9314∷FibMain.v10 =
                                                          x9296 x9300;
                in x9314:x9316;
        Prelude.[] → "";)
FibMain.daeh = ΛFibMain.v15.λx9284∷[FibMain.v15].(case x9284 of
        (x9286∷FibMain.v15):(x9288∷[FibMain.v15]) → x9286;
        Prelude.[] →
            <⊥:test/fibmain.hs:5:13: Unmatched pattern∷FibMain.v15>;)
ghc:
...
daeh :: %forall a . [] a -> a =
    \ @ a (ds::[] a) ->
  %case (a) ds %of (wild::[] a)
    {[] ->
       GHC.Err.patError @ a
       ("test/fibmain.hs:5:0-14|function daeh"::Addr#);
     : (x::a) (xs::[] a) ->
       x};
  pam :: %forall a a1 . (a -> a1) ->
      	[] a -> [] a1 =
    \ @ a @ a1 ->
  %let %rec
       {pam1 :: (a -> a1) -> [] a -> [] a1 =
      \ (f::a -> a1) (ds::[] a) ->
          %case (([] a1)) ds %of (wild::[] a)
            {[] ->
      	 [] @ a1;
             : (x::a) (xs::[] a) ->
      	 : @ a1 (f x) (pam1 f xs)}}
  %in pam1;
  main :: %forall a . [] ([] a) ->
            [] a =
    \ @ a (xs::[] ([] a)) ->
  FibMain.pam @ ([] a) @ a (FibMain.daeh @ a) xs;
I don't think a common compiler level core is forthcoming :)


        John


--
John Meacham - ⑆repetae.net⑆john⑈