doc/hcar/Cabal-201811.tex

   1 % Cabal-MC.tex
   2 \begin{hcarentry}{Cabal}
   3 \label{cabal}
   4 \label{hackage}
   5 \label{hackagedb}
   6 \report{Mikhail Glushenkov}%11/18
   7 \status{Stable, actively developed}
   8 \makeheader
   9
  10 \subsubsection*{Background}
  11
  12 Cabal is the standard packaging system for Haskell software. It
  13 specifies how Haskell libraries and applications can be packaged so
  14 that it is easy for consumers to use them, or re-package them,
  15 regardless of the Haskell implementation or installation platform.
  16
  17 \texttt{cabal-install} is the command line interface for the Cabal and
  18 Hackage system. It provides a program \texttt{cabal} which has
  19 sub-commands for installing, managing, and developing Haskell packages.
  20
  21 \subsubsection*{Recent Progress}
  22
  23 We've recently produced the first releases of
  24 Cabal/\texttt{cabal-install} from the 2.4 series. Bugfix releases from
  25 the same branch are in the works at the time of writing and should be out soon.
  26
  27 Almost 600 commits were made to the \texttt{master} branch by
  28 \href{https://gist.github.com/23Skidoo/7f07c309776574039b9cc7e29cfaf069}{48
  29   different contributors} since the 2.2 release. Among the highlights
  30 are:
  31
  32 \begin{compactitem}
  33
  34 \item Massive improvements to the
  35   \href{https://cabal.readthedocs.io/en/latest/nix-local-build-overview.html#nix-style-local-builds}{\texttt{new-build}
  36     feature}
  37   \href{https://typedr.at/posts/what-i-did-on-my-summer-vacation/}{made
  38     by Alexis Williams during GSoC 2018}, as well as many other
  39   contributors. Among other things, \texttt{new-install},
  40   \texttt{new-sdist}, \texttt{new-clean}, and \texttt{new-update}
  41   commands are now fully implemented, \texttt{new-repl} works outside
  42   of projects, and \texttt{new-run} can now be used to run scripts
  43   (either with \texttt{cabal new-run foo.hs} or in a shebang
  44   interpreter mode).
  45
  46 \item It's now possible
  47   \href{https://cabal.readthedocs.io/en/latest/nix-local-build.html#specifying-packages-from-remote-version-control-locations}{to
  48     specify packages from remote version control locations
  49     (e.g. GitHub) in \texttt{cabal.project}} (as well as local/remote
  50   tarballs). Work done by Duncan Coutts with the help of Alexis
  51   Williams, \textbf{@quasicomputational}, and others.
  52
  53 \item Improvements to the wildcard syntax: a
  54   \href{https://cabal.readthedocs.io/en/latest/developing-packages.html#pkg-field-data-files}{limited
  55     form of recursive matching} (\texttt{data-files:~audio/**/*.mp3})
  56   is now allowed. Work done by \textbf{@quasicomputational}.
  57
  58 \item Lots of bug fixes and performance improvements.
  59
  60 \end{compactitem}
  61
  62 \subsubsection*{Looking Forward}
  63
  64 We plan to make the next major Cabal/\texttt{cabal-install} release
  65 (3.0) around the same time GHC 8.8 is going to be released (February
  66 2019). Main features currently targeted at this milestone are:
  67
  68 \begin{compactitem}
  69
  70 \item \texttt{new-build} will become the default mode of
  71   operation. Old-style commands will still be accessible under the
  72   \texttt{v1-} prefix.
  73
  74 \item Multiple public libraries feature implemented by Francesco
  75   Gazzetta during GSoC 2018. This will allow to define more than one
  76   public library in a single \texttt{.cabal} package, which is useful
  77   for large projects such as \texttt{lens}, as well as Backpack-heavy
  78   libraries. This
  79   \href{https://github.com/haskell/cabal/pull/5526}{has already been
  80     merged to \texttt{master}}; Francesco continues to polish and
  81   improve the implementation in preparation for its initial release.
  82
  83 \item A split of the Cabal library into a pure \texttt{cabal-lib-core}
  84   part (parser and foundational data types) and an effectful
  85   \texttt{cabal-lib-build} part (build system bits); likewise, the
  86   constraint solver part of \texttt{cabal-install} will be
  87   moved into its own library \texttt{cabal-lib-solver}, and the
  88   \texttt{cabal-install} package renamed to \texttt{cabal}.
  89
  90 \item A revamped homepage, rewritten user manual, and automated build
  91   bots for producing binaries. Help in this area would be appreciated!
  92
  93 \end{compactitem}
  94
  95 We would like to encourage people considering contributing to take a
  96 look at \href{https://github.com/haskell/cabal/issues/}{the bug
  97   tracker on GitHub}, take part in discussions on tickets and pull
  98 requests, or submit their own. The bug tracker is reasonably well
  99 maintained and it should be fairly clear to new contributors what
 100 is in need of attention and which tasks are considered relatively
 101 easy. Additionally,
 102 \href{https://github.com/haskell/cabal/wiki/ZuriHac-2018}{the list
 103   of potential projects from the latest hackathon} and the tickets
 104 marked
 105 \href{https://github.com/haskell/cabal/issues?q=is\%3Aopen+is\%3Aissue+label\%3A\%22meta\%3A+easy\%22}{“easy”}
 106 and
 107 \href{https://github.com/haskell/cabal/issues?q=is\%3Aopen+is\%3Aissue+label\%3Anewcomer}{“newcomer”}
 108 can be used as a source of ideas for what to work on.
 109
 110 For more in-depth discussions there is also the
 111 \href{https://mail.haskell.org/mailman/listinfo/cabal-devel}{\texttt{cabal-devel}
 112   mailing list} and the
 113 \href{http://ircbrowse.net/browse/hackage}{\texttt{\#hackage} IRC
 114   channel on FreeNode}.
 115
 116 \FurtherReading
 117 \begin{compactitem}
 118 \item Cabal homepage:\hfill\url{https://www.haskell.org/cabal/}\\
 119 \item Cabal on GitHub:\hfill\url{https://github.com/haskell/cabal}
 120 \end{compactitem}
 121 \end{hcarentry}