HaskDogs

Haskdogs is a shellscript-like tool which creates tag file for entire haskell project directory. It takes into account first-level dependencies by recursively scanning imports and adding matching projects to the dependency list. Next, Haskdogs uses cabal or stack to unpack their sources into a temporary directory, which is ~/.haskdogs by default. Finally, hasktags is called to produce the tags file.

As a result, programmer can use his/her text editor supporting tags (e.g. vim) to jump directly to definition of any standard or foreign function he/she uses.

Note, that haskdogs relies on some GNU programs as well as on Unix shell commands such as 'cd', 'mkdir' and so on. Also it would run 'stack' and ghc-pkg' in order to obtain package information.

INSTALL

Check the dependencies. Currently they are: stack, hasktags, GNU find, which and shell.

Please follow stack's documentation(https://github.com/commercialhaskell/stack) to install stack.

$ stack install hasktags haskdogs

Make sure that PATH contains path to your stack binaries directory ($HOME/.local/bin by default).

RUNNING

Make sure yoy have installed hasktags and put it in PATH. cd to your Haskell project dir $ cd $HOME/my-haskell-project Run haskdogs without arguments to generate tags file in Vim-compatible format $ haskdogs

Emacs users would probably want to add -e hasktags option to build Emacs-compatible TAGS.

$ haskdogs --help haskdogs - Recursive hasktags-based TAGS generator for a Haskell project Usage: haskdogs [--version] [-d|--dir-list FILE] [-f|--file-list FILE] [-i|--input FILE] [--hasktags-args OPTS] [--stack-args OPTS] [--ghc-pkg-args OPTS] [--use-stack ARG] [--deps-dir PATH] [--raw] [-q|--quiet] [OPTS] Available options: -h,--help Show this help text --version Show version number -d,--dir-list FILE File containing directory list to process (use '-' to read from stdin) -f,--file-list FILE File containing Haskell sources to process (use '-' to read from stdin) -i,--input FILE Single Haskell file to process (use '-' to read Haskell source from stdin) --hasktags-args OPTS Arguments to pass to hasktags. -c -x is the default. Not for raw mode. --stack-args OPTS Arguments to pass to stack --ghc-pkg-args OPTS Arguments to pass to ghc-pkgs --use-stack ARG Execute ghc-pkg via stack, arg is ON, OFF or AUTO (the default) --deps-dir PATH Specify the directory PATH to place the dependencies of the project. Default is [$HOME/.haskdogs] --raw Don't execute hasktags, print list of files to tag on the STDOUT. The output may be piped into hasktags like this: `haskdogs --raw | hasktags -c -x STDIN' -q,--quiet Don't print verbose messages OPTS More hasktags options, use `--' to pass flags starting with `-'. Not for raw mode.

The following error could be caused by (over)strict Haskell policy regarding Unicode locale:

haskdogs: fd:5: hGetContents: invalid argument (invalid byte sequence)

It usually happens when the program tries to print Unicode character to non-unicode console. In order to overcome, try the following setting:

export LANG=en_US.UTF8

VIM HINT

Hasdogs (and underlying Hasktags) use simple scanning algorithm so it may become confused facing functions with identical names. In this case Hasktags includes all of them in the output file so user has to decide which tag to jump to. Vim offers :tag and :ts commands to deal with such situations but it is somewhat cumbersome to type them every time.

To speedup things a bit I use the following vim binding. It iterates over all same tags quickly with just one C-] command.

" Cyclic tag navigation {{{ let g:rt_cw = '' function! RT() let cw = expand('<cword>') try if cw != g:rt_cw execute 'tag ' . cw call search(cw,'c',line('.')) else try execute 'tnext' catch /.*/ execute 'trewind' endtry call search(cw,'c',line('.')) endif let g:rt_cw = cw catch /.*/ echo "no tags on " . cw endtry endfunction map <C-]> :call RT()<CR> " }}}

Just copy the code above to your ~/.vimrc and reload the vim.

NIX NOTE

The easiest way to generate Hakell tags on Nix-machine is to run Haskdogs from nix-shell as follows:

nix-shell -p haskellPackages.haskdogs haskellPackages.hasktags haskellPackages.cabal-install ghc (nix-shell) $ haskdogs

TIPS