| I'd like to know what the function GHC.Prim.realWorld does exactlly | in the STG code below: Think of it as a fixed value. We want the join point $w$j to be a function, with at least one argument, otherwise it'll be evaluated eagerly (since it has a primitive type), which is semantically wrong. It's rather like saying (\().e), only cheaper, because passing () requires you to actually pass a value, whereas the 'realword' token has a type that says "you don't need to pass anything at runtime". GHC.Prim is a built-in module for functions and types that can't be defined in Haskell. The functions in GHC.Prim are enumerated in ghc/compiler/prelude/primops.txt.pp Simon | | PrelBase.divInt# = | \r [x# y#] | let-no-escape { | $w$j = | sat-only \r [w] | case <# [x# 0] of wild { | GHC.Base.False -> quotInt# [x# y#]; | GHC.Base.True -> | case ># [y# 0] of wild1 { | GHC.Base.True -> | case +# [x# 1] of sat_s10t { | __DEFAULT -> | case quotInt# [sat_s10t y#] of sat_s10w { | __DEFAULT -> -# [sat_s10w 1]; | }; | }; | GHC.Base.False -> quotInt# [x# y#]; | }; | }; | } in | case ># [x# 0] of wild { | GHC.Base.False -> $w$j GHC.Prim.realWorld#; | GHC.Base.True -> | case <# [y# 0] of wild1 { | GHC.Base.True -> | case -# [x# 1] of sat_s10I { | __DEFAULT -> | case quotInt# [sat_s10I y#] of sat_s10L { | __DEFAULT -> -# [sat_s10L 1]; | }; | }; | GHC.Base.False -> $w$j GHC.Prim.realWorld#; | }; | }; | | Finally, where is the module GHC.Prim defined ? I've looked for it | in GHC source directories but I haven't found it. Is it part of the | runtime system ? | | Thanks in advance, | | -- | ________________________________ | Monique Louise B.Monteiro | Msc Student in Computer Science | Center of Informatics | Federal University of Pernambuco