Hi Facundo, > The program below when loaded in ghci prints always False, and when > compiled with ghc it prints True
>From above, I guess the code is not compiled in ghci, which means byte-code is used insted of object-code. If what matter here is "to get same result in ghci and compiled code", invoking ghci with object code compilation option[1] may help. E.g. start ghci with: $ ghci -fobject-code Below is a sample session with your code. I saved it as "UCSN.hs". $ ls UCSN.hs $ ghc-7.4.1 --interactive UCSN.hs GHCi, version 7.4.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling UCSN ( UCSN.hs, interpreted ) Ok, modules loaded: UCSN. ghci> :main type enter False ghci> :q Leaving GHCi. Invoking again, with "-fobject-code". Note the absense of "interpreted" message: $ ghc-7.4.1 --interactive -fobject-code UCSN.hs GHCi, version 7.4.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [1 of 1] Compiling UCSN ( UCSN.hs, UCSN.o ) Ok, modules loaded: UCSN. ghci> :main type enter True ghci> :q Leaving GHCi. Now we have "UCSN.hi" and "UCSN.o". $ ls UCSN.hi UCSN.hs UCSN.o Invoking ghci again, without "-fobject-code". No "interpreted" message. Showing 'True' with main. $ ghc-7.4.1 --interactive UCSN.hs GHCi, version 7.4.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Ok, modules loaded: UCSN. ghci> :main type enter True ghci> :q Leaving GHCi. Hope these help. [1]: http://www.haskell.org/ghc/docs/latest/html/users_guide/options-phases.html#options-codegen Regards, -- Atsuro On Thu, Jun 28, 2012 at 6:41 AM, Facundo Domínguez <facundoming...@gmail.com> wrote: > Hi, > The program below when loaded in ghci prints always False, and when > compiled with ghc it prints True. I'm using ghc-7.4.1 and I cannot > quite explain such behavior. Any hints? > > Thanks in advance, > Facundo > > {-# LANGUAGE GADTs #-} > import System.Mem.StableName > import Unsafe.Coerce > import GHC.Conc > > data D where > D :: a -> b -> D > > main = do > putStr "type enter" > s <- getLine > let i = fromEnum$ head$ s++"0" > d = D i i > case d of > D a b -> do > let a' = a > sn0 <- pseq a'$ makeStableName a' > sn1 <- pseq b$ makeStableName b > print (sn0==unsafeCoerce sn1) > > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users@haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
