Add juvix clean to remove project build artifact directory (#2018)

This PR adds the `juvix clean` command to the CLI that removes the Juvix
project build directory.

It respects the `--internal-build-dir` global option:

```
$ juvix compile Foo.juvix --internal-build-dir /tmp/build
$ juvix clean --internal-build-dir /tmp/build
```

In addition this PR fixes the `juvix format` program brief description
string. This was too long for the `juvix --help` display. The longer
description is now only displayed when `juvix format --help` is run.

* Closes https://github.com/anoma/juvix/issues/2017

app/Commands/Clean.hs

@@ -0,0 +1,8 @@
+module Commands.Clean where
+
+import Commands.Base
+
+runCommand :: Members '[Files, App] r => Sem r ()
+runCommand = do
+  buildDir <- askBuildDir
+  whenM (directoryExists' buildDir) (removeDirectoryRecursive' buildDir)

app/TopCommand.hs

@@ -1,6 +1,7 @@
 module TopCommand where
 
 import Commands.Base hiding (Format)
+import Commands.Clean qualified as Clean
 import Commands.Compile qualified as Compile
 import Commands.Dev qualified as Dev
 import Commands.Doctor qualified as Doctor
@@ -32,6 +33,7 @@ runTopCommand = \case
   Dev opts -> Dev.runCommand opts
   Typecheck opts -> Typecheck.runCommand opts
   Compile opts -> Compile.runCommand opts
+  Clean -> runFilesIO Clean.runCommand
   Eval opts -> Eval.runCommand opts
   Html opts -> Html.runCommand opts
   JuvixRepl opts -> Repl.runCommand opts

app/TopCommand/Options.hs

@@ -19,6 +19,7 @@ data TopCommand
   | DisplayHelp
   | Typecheck TypecheckOptions
   | Compile CompileOptions
+  | Clean
   | Eval EvalOptions
   | Html HtmlOptions
   | Dev Dev.DevCommand
@@ -87,7 +88,8 @@ parseUtility =
           commandInit,
           commandDev,
           commandRepl,
-          commandFormat
+          commandFormat,
+          commandClean
         ]
     )
   where
@@ -121,18 +123,25 @@ parseUtility =
       command "format" $
         info
           (JuvixFormat <$> parseFormat)
-          ( progDescDoc
+          ( headerDoc
               ( Just
                   ( vsep
-                      [ "Format a Juvix file or Juvix project",
+                      [ "juvix format is used to format Juvix source files.",
                         "",
-                        "When the command is run with an unformatted file it prints the reformatted source to standard output.",
-                        "When the command is run with a project directory it prints a list of unformatted files in the project."
+                        "Given an unformatted file, it prints the reformatted source to standard output.",
+                        "Given a project directory it prints a list of unformatted files in the project."
                       ]
                   )
               )
+              <> progDesc "Format a Juvix file or Juvix project"
           )
 
+    commandClean :: Mod CommandFields TopCommand
+    commandClean =
+      command
+        "clean"
+        (info (pure Clean) (progDesc "Delete build artifacts"))
+
 commandCheck :: Mod CommandFields TopCommand
 commandCheck =
   command "typecheck" $

tests/smoke/Commands/clean.smoke.yaml

@@ -0,0 +1,61 @@
+working-directory: ./../../../
+
+tests:
+  - name: clean-with-no-build-dir
+    command:
+      shell:
+        - bash
+      script: |
+        temp=$(mktemp -d)
+        trap 'rm -rf -- "$temp"' EXIT
+        cd $temp
+        juvix clean
+    stdout: ""
+    exit-status: 0
+
+  - name: clean-with-default-build-dir
+    command:
+      shell:
+        - bash
+      script: |
+        temp=$(mktemp -d)
+        trap 'rm -rf -- "$temp"' EXIT
+        cd ./examples/milestone/HelloWorld
+        juvix compile -o $temp/Hello HelloWorld.juvix
+        juvix clean
+        [ -d $temp/.juvix-build ]
+    stdout: ""
+    exit-status: 1
+
+  - name: clean-with-internal-build-dir
+    command:
+      shell:
+        - bash
+      script: |
+        temp=$(mktemp -d)
+        trap 'rm -rf -- "$temp"' EXIT
+        temp_build_dir=$(mktemp -d)
+        trap 'rm -rf -- "$temp_build_dir"' EXIT
+        cd ./examples/milestone/HelloWorld
+        juvix compile -o $temp/Hello HelloWorld.juvix --internal-build-dir "$temp_build_dir"
+        juvix --internal-build-dir "$temp_build_dir" clean
+        [ -d $temp_build_dir ]
+    stdout: ""
+    exit-status: 1
+
+  - name: clean-with-internal-build-dir-does-not-remove-default-build-dir
+    command:
+      shell:
+        - bash
+      script: |
+        temp=$(mktemp -d)
+        trap 'rm -rf -- "$temp"' EXIT
+        temp_build_dir=$(mktemp -d)
+        trap 'rm -rf -- "$temp_build_dir"' EXIT
+        cp -r ./examples/milestone/HelloWorld/. $temp
+        cd $temp
+        juvix compile HelloWorld.juvix
+        juvix --internal-build-dir "$temp_build_dir" clean
+        [ -d $temp/.juvix-build ]
+    stdout: ""
+    exit-status: 0