A utility for managing Hackage dependencies from the command line.

cabal-edit

This is an extension to Haskell's package manager Cabal to allow you to add, remove, and upgrade dependencies by modifying your cabal file from the command line. This behaves similar to install --save commands in other package managers.

cabal-edit add
cabal-edit list
cabal-edit upgrade
cabal-edit remove

For example to setup a new project one often wants to add common dependencies like text and aeson. We can use cabal-edit to automatically append these to our dependency list and deduce the latest versions from Hackage.

$ cabal init --lib --cabal-version=3.0    

$ cabal-edit add aeson                
Adding dependency: aeson ^>=1.5 to sample.cabal

$ cabal-edit add text 
Adding dependency: text ^>=1.2 to sample.cabal

If we want to depend on a specific version of aeson, we can pass this explicitly as an argument.

$ cabal-edit add aeson==1.4.0.0

The Hackage database can be queried from the command line to search for all available versions to use with the list command.

$ cabal-edit list filepath
1.0
1.1.0.0
1.1.0.1
1.1.0.2
1.1.0.3
1.1.0.4
1.2.0.0
1.2.0.1
1.3.0.0
1.3.0.1
1.3.0.2
1.4.0.0
1.4.1.0
1.4.1.1
1.4.1.2
1.4.2
1.4.2.1

You may wish to then run cabal-fmt on the outputted file to canonicalise it. Auto-formatting of the outputted cabal may be added in the future.

Installation

Download this repository.

$ git clone [email protected]:sdiehl/cabal-edit.git
$ cd cabal-edit

Then install either with Stack, Cabal or Nix.

$ stack install 
$ cabal install --installdir=/home/$USER/.local/bin
$ nix-build -A cabal-edit

Note: This library links directly against Cabal, so you must be using the same version of Cabal you intend to compile your package against. It is reccomened to use Cabal > 3.0 to support modern versioning schemes.

Shell Completions

We can tab complete on the Hackage package index we install the local completions for you shell. Run one of the following commands to generate the shell completer appropriate to your shell. Then add the output to one of ~/.zshrc, ~/.bashrc or ~/.config/fish/config.fish.

$ cabal-edit --zsh-completion-script cabal-edit
$ cabal-edit --bash-completion-script cabal-edit
$ cabal-edit --fish-completion-script cabal-edit

This will completion against the Hackage database prefixed by name.

$ cabal-edit add gh
zsh: do you wish to see all 103 possibilities (15 lines)?
$ cabal-edit add ghc-pa
ghc-parmake  ghc-parser   ghc-paths

bash

_cabal-edit()
{
    local CMDLINE
    local IFS=$'\n'
    CMDLINE=(--bash-completion-index $COMP_CWORD)

    for arg in ${COMP_WORDS[@]}; do
        CMDLINE=(${CMDLINE[@]} --bash-completion-word $arg)
    done

    COMPREPLY=( $(cabal-edit "${CMDLINE[@]}") )
}

complete -o filenames -F _cabal-edit cabal-edit

zsh

#compdef cabal-edit

local request
local completions
local word
local index=$((CURRENT - 1))

request=(--bash-completion-enriched --bash-completion-index $index)
for arg in ${words[@]}; do
  request=(${request[@]} --bash-completion-word $arg)
done

IFS=$'\n' completions=($( cabal-edit "${request[@]}" ))

for word in $completions; do
  local -a parts

  # Split the line at a tab if there is one.
  IFS=$'\t' parts=($( echo $word ))

  if [[ -n $parts[2] ]]; then
     if [[ $word[1] == "-" ]]; then
       local desc=("$parts[1] ($parts[2])")
       compadd -d desc -- $parts[1]
     else
       local desc=($(print -f  "%-019s -- %s" $parts[1] $parts[2]))
       compadd -l -d desc -- $parts[1]
     fi
  else
    compadd -f -- $word
  fi
done

fish

 function _cabal-edit
    set -l cl (commandline --tokenize --current-process)
    # Hack around fish issue #3934
    set -l cn (commandline --tokenize --cut-at-cursor --current-process)
    set -l cn (count $cn)
    set -l tmpline --bash-completion-enriched --bash-completion-index $cn
    for arg in $cl
      set tmpline $tmpline --bash-completion-word $arg
    end
    for opt in (cabal-edit $tmpline)
      if test -d $opt
        echo -E "$opt/"
      else
        echo -E "$opt"
      end
    end
end

complete --no-files --command cabal-edit --arguments '(_cabal-edit)'