Looks wrong! You don't say what version. Not happening with 6.6.1 or the 6.8 release candidate ghc-6.8.0.20070916 -c -ddump-stg T1.hs -O ==================== STG syntax: ==================== T1.map = \r [f_s6M ds_s6H] case ds_s6H of wild_s6S { [] -> [] []; : x_s6L xs_s6P -> let { sat_s6R = \u [] T1.map f_s6M xs_s6P; } in let { sat_s6O = \u [] f_s6M x_s6L; } in : [sat_s6O sat_s6R]; }; SRT(T1.map): [] bash-3.1$ ghc-6.6.1 -c -ddump-stg T1.hs -O ==================== STG syntax: ==================== T1.map = \r [f_sem ds_seh] case ds_seh of wild_ses { [] -> [] []; : x_sel xs_sep -> let { sat_ser = \u [] T1.map f_sem xs_sep; } in let { sat_seo = \u [] f_sem x_sel; } in : [sat_seo sat_ser]; }; SRT(T1.map): [] bash-3.1$ | -----Original Message----- | From: glasgow-haskell-users-bounces@haskell.org [mailto:glasgow-haskell-users-bounces@haskell.org] On | Behalf Of Victor Nazarov | Sent: 21 September 2007 12:05 | To: glasgow-haskell-users@haskell.org | Subject: Additional thunk for function | | What is the purpose for GHC to allocate a thunk for some functions? | Why Test.map is not a function, but updatable thunk, which should | become equal to the function just after the first call? Here is the | details: | | > % ghc -c test.hs -ddump-stg | > | > ==================== STG syntax: ==================== | > Test.map = | > \u [] | > let { | > map1_sdR = | > \r [f_sdN ds_sdI] | > case ds_sdI of wild_sdU { | > [] -> [] []; | > : x_sdM xs_sdQ -> | > let { sat_sdT = \u [] map1_sdR f_sdN xs_sdQ; } in | > let { sat_sdP = \u [] f_sdN x_sdM; } in : [sat_sdP sat_sdT]; | > }; | > } in map1_sdR; | > SRT(Test.map): [] | > | > | > % cat test.hs | > module Test where | > | > map f [] = [] | > map f (x:xs) = f x : Test.map f xs | | -- | Thanks in advance | Victor | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users