🇺🇸🇺🇸🇺🇸 Freedom Formatter 🇺🇸🇺🇸🇺🇸

A fork of Elixir's code formatter, with added freedom.

Freedom Formatter is a formatter plugin for Elixir files (.ex and .exs). It supports all features of the standard code formatter (forked from Elixir 1.19.1), as well as additional features.

Added Features

• :trailing_comma - if set true, multi-line list, map, and struct literals will include a trailing comma after the last item or pair in the data structure. Does not affect argument lists nor tuples. Does not affect lists/maps/structs rendered on a single line either.

# trailing_comma: false
example = %{
  foo: 42,
  bar: 44
}
# trailing_comma: true
example = %{
  foo: 42,
  bar: 44,
}

• :single_clause_on_do - if set to true, will format case with single pattern with the pattern inline, like:

# single_clause_on_do: false
case expr do
  pattern -> body
end

# single_clause_on_do: true
case expr do pattern ->
  body
end

• :local_pipe_with_parens - FreedomFormatter introduced this feature for Elixir 1.14+, years before Elixir 1.19 introduced it under the name :migrate_call_parens_on_pipe. Compatibility maintained, either names can be used.

Usage

Install by adding the package to your mix.exs

{:freedom_formatter, ">= 2.0.0", only: :dev}

Specify this package as a plugin for the formatter in .formatter.exs:

# .formatter.exs
[
  inputs: [
    # ...
  ],
  plugins: [
    # ...
    # Add this:
    FreedomFormatter,
  ],

  # Additional options are now supported:
  trailing_comma: true,
  migrate_call_parens_on_pipe: true,
]

An elixir bug (fixed but not released yet) currently requires the app FreedomFormatter to be compiled first before attempting to format.

# Do this:
mix deps.get
mix compile
# Before you do that:
mix format

Why

Elixir's code formatter does not intend to support trailing commas, or indeed any additional settings. See Elixir issues #7689 and #6646 for more information.

Project Goals

• To provide a compatible alternative to the Elixir formatter, available separately from the core Elixir distribution
• To allow developers and teams to benefit from standardized code formatting while retaining a style they find more productive
• To be a testbed for new formatting features and options, maintaining the easiest possible path to possible inclusion in core Elixir.

Authorship and License

Freedom Formatter is released under the same license as Elixir itself, the Apache License Version 2.0, included here as the file LICENSE.

Freedom Formatter is based upon the Elixir code formatter, whose implementation and tests are included in this project. The core Elixir formatter was written by José Valim, with contributions from Andrea Leopardi and others.

Authored by Pete Gamache. Maintance by Marc-André Lafortune.

Notes

• For each new minor version of elixir, this project gets a new branch with a completely rewritten history:
  • Using interactive rebase, edit the third commit "Import stock Elixir"
  • Copy files from recent Elixir version (using cp shown in commit message)
  • Amend the commit, update the Elixir version and hash tag in commit message.
  • Continue with the rebase, fixing potential merge conflicts / test failures.
  • Edit the release commit with up-to-date versions for package & Elixir
• This project uses semantic versioning.

Changelog

v2.1.3: Updated for Elixir 1.19.0+

v2.1.2: Updated for Elixir 1.18.0+

v2.1.1: Updated for Elixir 1.17.0+

v2.1.0: Adds local_pipe_with_parens option. Requires Elixir 1.14.0+

v2.0.0: Now a formatter plugin; as such it requires Elixir 1.13.2+