purescript-pursfmt

Configurable syntax formatter for PureScript.

npm install --save-dev pursfmt

Do not install it globally, so that different PureScript projects can use different versions of pursfmt.

Also available for Nix via Nixpkgs 22.11+ and Easy PureScript Nix

You can use pursfmt to format files in place or via stdin / stdout (which is useful for editor integration):

pursfmt format-in-place "src/**/*.purs"

pursfmt format < MyFile.purs

You can also use pursfmt to verify whether files have already been formatted. This is often useful to verify, in continuous integration, that all project files are formatted according to the configuration. Files that would be changed by running format-in-place are listed out.

pursfmt check "src/**/*.purs"
All files are formatted.

You can see all configuration that pursfmt accepts using the --help flag for the command you are using:

pursfmt format-in-place --help

Some common options include:

• --indent to set the number of spaces used in indentation, which defaults to 2 spaces
• --arrow-first or --arrow-last to control whether type signatures put arrows first on the line or last on the line (purty-style), which defaults to arrow-first.

You can generate a .pursfmt.yaml using the generate-config command. For example:

pursfmt generate-config --indent 2 --width 80 --arrow-last

If a .pursfmt.yaml file is found, it will be used in lieu of CLI arguments.

To support correct operator precedence without having to parse your entire source tree (potentially for a single file), pursfmt uses a pre-baked operator precedence table. By default, pursfmt ships with a table built from the core and contrib organizations. If you need support for more operators, you can generate your own table using the generate-operators command.

spago sources | xargs pursfmt generate-operators > .pursfmtoperators
$ pursfmt generate-config --arrow-first --unicode-never --operators .pursfmtoperators

• Spacemacs
• Vim
• VS Code

Spacemacs' Purescript layer supports formatting using pursfmt out of the box.

You can run the formatter manually with either M-x spacemacs/purescript-format or with the shortcut SPC m =.

To enable automatic formatting of the buffer on save, enable purescript-fmt-on-save in your spacemacs config:

  (setq-default dotspacemacs-configuration-layers '(
    (purescript :variables
                purescript-fmt-on-save t)))

Add to your other fixers .vimrc or $XDG_CONFIG_HOME/neovim/init.vim

let b:ale_fixers = { 'purescript': [ 'pursfmt' ] }
" suggested to fix on save
let g:ale_fix_on_save = 1

Add to your .vimrc or $XDG_CONFIG_HOME/neovim/init.vim

let g:neoformat_enabled_purescript = ['pursfmt']

The PureScript IDE plugin for VS Code supports pursfmt as a built-in formatter in versions after 0.25.1. Choose pursfmt from the list of supported formatters in the settings, or add this to your settings.json:

"purescript.formatter": "pursfmt"

For local development pointing to the output directory:

npm run build
$ ./bin/index.dev.js --help

For a local production build pointing to the bundle directory:

npm run bundle
$ ./bin/index.js --help

If you would like to use your local build of pursfmt in your editor, use path to bin/index.js instead of the pursfmt binary in your settings. For example, instead of setting the format command to pursfmt format, set it to $PURSFMT_DIR/bin/index.js format where $PURSFMT_DIR is the location of your checkout of this repository.

To accept snapshot tests:

npm run test -- -a "--accept"

npm run generate-default-operators

This project was originally forked from purescript-tidy.