Add ormolu and fourmolu, remove brittany (#221)

Found while trying to `make fmt-build` that the installer for `brittany`
was broken, and couldn't fix it.

This removes brittany, and adds the ormolu and fourmolu formatters for
haskell, and sets ormolu as the default for haskell-mode.

---------

Co-authored-by: Radon Rosborough <radon@intuitiveexplanations.com>

CHANGELOG.md

@@ -43,7 +43,9 @@ The format is based on [Keep a Changelog].
   for [Bazel Build](https://bazel.build/) ([#171]).
 * [`cmake-format`](https://github.com/cheshirekow/cmake_format)
   for [CMake](https://cmake.org/) ([#172]).
+* [`fourmolu`](https://github.com/fourmolu/fourmolu) for haskell
 * [`html-tidy`](https://www.html-tidy.org/) for HTML/XML ([#173]).
+* [`ormolu`](https://github.com/tweag/ormolu) for haskell.
 * [`perltidy`](https://perltidy.sourceforge.net/) for
   [perl](https://www.perl.org/) ([#175]).
 * [`rubocop`](https://github.com/rubocop/rubocop) for [ruby](https://www.ruby-lang.org/en/) ([#176]).

apheleia.el

@@ -57,6 +57,7 @@
     (dart-format . ("dart" "format"))
     (elm-format . ("elm-format" "--yes" "--stdin"))
     (fish-indent . ("fish_indent"))
+    (fourmolu . ("fourmolu"))
     (gawk . ("gawk" "-f" "-" "--pretty-print=-"))
     (gofmt . ("gofmt"))
     (gofumpt . ("gofumpt"))
@@ -88,6 +89,7 @@
     (nixfmt . ("nixfmt"))
     (ocamlformat . ("ocamlformat" "-" "--name" filepath
                     "--enable-outside-detected-project"))
+    (ormolu . ("ormolu"))
     (perltidy . ("perltidy" "--quiet" "--standard-error-output"))
     (phpcs . ("apheleia-phpcs"))
     (prettier

test/formatters/installers/fourmolu.bash

@@ -0,0 +1,4 @@
+apt-get install -y haskell-platform
+cabal update
+cabal install fourmolu
+cp "${HOME}/.cabal/bin/fourmolu" /usr/local/bin

test/formatters/installers/ormolu.bash

@@ -0,0 +1,4 @@
+apt-get install -y haskell-platform
+cabal update
+cabal install ormolu
+cp "${HOME}/.cabal/bin/ormolu" /usr/local/bin

test/formatters/samplecode/fourmolu/in.hs

@@ -0,0 +1,10 @@
+-- Foo performs foo and sometimes bar.
+
+foo :: Thoroughness
+  -> Int -> Int
+foo t x = if x > 20
+    then case t of
+           Thorough -> x + 50
+           Somewhat -> x + 20
+           NotAtAll -> 0
+    else 10 + 1

test/formatters/samplecode/fourmolu/out.hs

@@ -0,0 +1,13 @@
+-- Foo performs foo and sometimes bar.
+
+foo ::
+    Thoroughness ->
+    Int ->
+    Int
+foo t x =
+    if x > 20
+        then case t of
+            Thorough -> x + 50
+            Somewhat -> x + 20
+            NotAtAll -> 0
+        else 10 + 1

test/formatters/samplecode/ormolu/in.hs

@@ -0,0 +1,10 @@
+-- Foo performs foo and sometimes bar.
+
+foo :: Thoroughness
+  -> Int -> Int
+foo t x = if x > 20
+    then case t of
+           Thorough -> x + 50
+           Somewhat -> x + 20
+           NotAtAll -> 0
+    else 10 + 1

test/formatters/samplecode/ormolu/out.hs

@@ -0,0 +1,13 @@
+-- Foo performs foo and sometimes bar.
+
+foo ::
+  Thoroughness ->
+  Int ->
+  Int
+foo t x =
+  if x > 20
+    then case t of
+      Thorough -> x + 50
+      Somewhat -> x + 20
+      NotAtAll -> 0
+    else 10 + 1