October 2013 - Glasgow-haskell-users

Desugaring do-notation to Applicative
by Simon Marlow 05 Oct '13

05 Oct '13

Following a couple of discussions at ICFP I've put together a proposal for desugaring do-notation to Applicative: http://ghc.haskell.org/trac/ghc/wiki/ApplicativeDo I plan to implement this following the addition of Applicative as a superclass of Monad, which is due to take place shortly after the 7.8 branch is cut. Please discuss here, and I'll update the wiki page as necessary. Cheers, Simon

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carriage returns on Windows from quasi-quotes
by Greg Weber 05 Oct '13

05 Oct '13

A Windows user rerported using Data.Text.IO.writeFile to write out quasi-quoted text. writeFile automatically translates '\r' to "\r\n", so the user ended up writing out "\r\r\n" to a file. Haskell seems to be adopting the policy or removing '\r' from Haskell land. Is there any reason why quasi-quotes should not automatically strip carriage returns?

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Trying to compile ghc HEAD on xubuntu 13.04-x64
by Nathan Hüsken 04 Oct '13

04 Oct '13

Hey, because I have touble with ghci and packages with FFI, it was suggested to me to compile and use ghc HEAD. I am on xubuntu 13.04 64bit and try to do a perf build. It fails with: compiler/ghc.mk:478: warning: ignoring old commands for target `compiler/stage2/build/libHSghc-7.7.20131004-ghc7.7.20131004.so' "/home/ls/src/ghc/inplace/bin/haddock" --odir="libraries/ghc-prim/dist-install/doc/html/ghc-prim" --no-tmp-comp-dir --dump-interface=libraries/ghc-prim/dist-install/doc/html/ghc-prim/ghc-prim.haddock --html --hoogle --title="ghc-prim-0.3.1.0: GHC primitives" --prologue="libraries/ghc-prim/dist-install/haddock-prologue.txt" --optghc=-hisuf --optghc=dyn_hi --optghc=-osuf --optghc=dyn_o --optghc=-hcsuf --optghc=dyn_hc --optghc=-fPIC --optghc=-dynamic --optghc=-O --optghc=-H64m --optghc=-package-name --optghc=ghc-prim-0.3.1.0 --optghc=-hide-all-packages --optghc=-i --optghc=-ilibraries/ghc-prim/. --optghc=-ilibraries/ghc-prim/dist-install/build --optghc=-ilibraries/ghc-prim/dist-install/build/autogen --optghc=-Ilibraries/ghc-prim/dist-install/build --optghc=-Ilibraries/ghc-prim/dist-install/build/autogen --optghc=-Ilibraries/ghc-prim/. --optghc=-optP-include --optghc=-optPlibraries/ghc-prim/dist-install/build/autogen/cabal_macros.h --optghc=-package --optghc=rts-1.0 --optghc=-package-name --optghc=ghc-prim --optghc=-XHaskell98 --optghc=-XCPP --optghc=-XMagicHash --optghc=-XForeignFunctionInterface --optghc=-XUnliftedFFITypes --optghc=-XUnboxedTuples --optghc=-XEmptyDataDecls --optghc=-XNoImplicitPrelude --optghc=-O2 --optghc=-no-user-package-db --optghc=-rtsopts --optghc=-odir --optghc=libraries/ghc-prim/dist-install/build --optghc=-hidir --optghc=libraries/ghc-prim/dist-install/build --optghc=-stubdir --optghc=libraries/ghc-prim/dist-install/build libraries/ghc-prim/./GHC/Classes.hs libraries/ghc-prim/./GHC/CString.hs libraries/ghc-prim/./GHC/Debug.hs libraries/ghc-prim/./GHC/Magic.hs libraries/ghc-prim/dist-install/build/GHC/PrimopWrappers.hs libraries/ghc-prim/./GHC/IntWord64.hs libraries/ghc-prim/./GHC/Tuple.hs libraries/ghc-prim/./GHC/Types.hs libraries/ghc-prim/dist-install/build/autogen/GHC/Prim.hs +RTS -tlibraries/ghc-prim/dist-install/doc/html/ghc-prim/ghc-prim.haddock.t --machine-readable Haddock coverage: 100% ( 1 / 1) in 'GHC.IntWord64' 80% ( 8 / 10) in 'GHC.Types' 17% ( 1 / 6) in 'GHC.CString' 3% ( 2 / 63) in 'GHC.Tuple' 0% ( 0 / 3) in 'GHC.Debug' 0% ( 0 /366) in 'GHC.PrimopWrappers' 72% (813 /1132) in 'GHC.Prim' 100% ( 3 / 3) in 'GHC.Magic' 38% ( 6 / 16) in 'GHC.Classes' haddock: internal error: haddock: panic! (the 'impossible' happened) (GHC version 7.7.20131004 for x86_64-unknown-linux): Static flags have not been initialised! Please call GHC.parseStaticFlags early enough. Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug make[1]: *** [libraries/ghc-prim/dist-install/doc/html/ghc-prim/ghc-prim.haddock] Error 1 make: *** [all] Error 2 Suggestions? Thanks! Nathan

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RE: Desugaring do-notation to Applicative
by Neil Sculthorpe 02 Oct '13

02 Oct '13

While I really like applicative notation, sometimes naming intermediate results can make code a lot more readable. So I think supporting applicative do-notation would be beneficial. Neil On 02/10/13 07:00, p.k.f.holzenspies wrote: > > ---------------------------------------------------------------------- > > Message: 1 > Date: Wed, 2 Oct 2013 09:12:26 +0000 > From: <p.k.f.holzenspies(a)utwente.nl> > To: <iavor.diatchki(a)gmail.com>, <dag.odenhall(a)gmail.com> > Cc: marlowsd(a)gmail.com, glasgow-haskell-users(a)haskell.org, > simonpj(a)microsoft.com > Subject: RE: Desugaring do-notation to Applicative > Message-ID: > <E7F535B24A47D747A07D46C0AA82D43D0AB17531(a)EXMBX21.ad.utwente.nl> > Content-Type: text/plain; charset="utf-8" > > I thought the whole point of Applicative (at least, reading Connor?s paper) was to restore some function-application-style to the whole effects-thing, i.e. it was the very point *not* to resort to binds or do-notation. > > That being said, I?m all for something that will promote the use of the name ?pure? over ?return?. > > +1 for the Opt-In > > Ph. > >

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