Add main field to juvix.yaml (#2120)

- Closes #2067

This pr adds the field `main` to `juvix.yaml`. This field is optional
and should contain a path to a juvix file that is meant to be used for
the `compile` (and `dev compile`) command when no file is given as an
argument in the CLI. This makes it possible to simply run `juvix
compile` if the `main` is specified in the `jvuix.yaml`.

I have updated the `juvix.yaml` of the milestone examples.

---------

Co-authored-by: Paul Cadman <git@paulcadman.dev>
Co-authored-by: Jonathan Cubides <jonathan.cubides@uib.no>

app/App.hs

@@ -6,6 +6,7 @@ import GlobalOptions
 import Juvix.Compiler.Concrete.Translation.FromParsed.Analysis.PathResolver
 import Juvix.Compiler.Pipeline
 import Juvix.Data.Error qualified as Error
+import Juvix.Extra.Paths.Base
 import Juvix.Prelude.Pretty hiding
   ( Doc,
   )
@@ -23,6 +24,7 @@ data App m a where
   AskPackageGlobal :: App m Bool
   AskGlobalOptions :: App m GlobalOptions
   FromAppPathFile :: AppPath File -> App m (Path Abs File)
+  GetMainFile :: Maybe (AppPath File) -> App m (Path Abs File)
   FromAppPathDir :: AppPath Dir -> App m (Path Abs Dir)
   RenderStdOut :: (HasAnsiBackend a, HasTextBackend a) => a -> App m ()
   RunPipelineEither :: AppPath File -> Sem PipelineEff a -> App m (Either JuvixError (ResolverState, a))
@@ -48,6 +50,7 @@ runAppIO args@RunAppIOArgs {..} =
   interpret $ \case
     AskPackageGlobal -> return (_runAppIOArgsRoots ^. rootsPackageGlobal)
     FromAppPathFile p -> embed (prepathToAbsFile invDir (p ^. pathPath))
+    GetMainFile m -> getMainFile' m
     FromAppPathDir p -> embed (prepathToAbsDir invDir (p ^. pathPath))
     RenderStdOut t
       | _runAppIOArgsGlobalOptions ^. globalOnlyErrors -> return ()
@@ -77,10 +80,28 @@ runAppIO args@RunAppIOArgs {..} =
     ExitJuvixError e -> do
       printErr e
       embed exitFailure
-    ExitMsg exitCode t -> embed (putStrLn t >> hFlush stdout >> exitWith exitCode)
+    ExitMsg exitCode t -> exitMsg' exitCode t
     SayRaw b -> embed (ByteString.putStr b)
   where
+    exitMsg' :: ExitCode -> Text -> Sem r x
+    exitMsg' exitCode t = embed (putStrLn t >> hFlush stdout >> exitWith exitCode)
+    getMainFile' :: Maybe (AppPath File) -> Sem r (Path Abs File)
+    getMainFile' = \case
+      Just p -> embed (prepathToAbsFile invDir (p ^. pathPath))
+      Nothing -> case pkg ^. packageMain of
+        Just p -> embed (prepathToAbsFile invDir p)
+        Nothing -> missingMainErr
+    missingMainErr :: Sem r x
+    missingMainErr =
+      exitMsg'
+        (ExitFailure 1)
+        ( "A path to the main file must be given in the CLI or specified in the `main` field of the "
+            <> pack (toFilePath juvixYamlFile)
+            <> " file"
+        )
     invDir = _runAppIOArgsRoots ^. rootsInvokeDir
+    pkg :: Package
+    pkg = _runAppIOArgsRoots ^. rootsPackage
     g :: GlobalOptions
     g = _runAppIOArgsGlobalOptions
     printErr e =

app/Commands/Compile.hs

@@ -11,8 +11,8 @@ import Juvix.Compiler.Core.Transformation.DisambiguateNames qualified as Core
 
 runCommand :: (Members '[Embed IO, App] r) => CompileOptions -> Sem r ()
 runCommand opts@CompileOptions {..} = do
-  inputFile <- fromAppPathFile _compileInputFile
-  Core.CoreResult {..} <- runPipeline _compileInputFile upToCore
+  inputFile <- getMainFile _compileInputFile
+  Core.CoreResult {..} <- runPipeline (AppPath (preFileFromAbs inputFile) True) upToCore
   let arg =
         Compile.PipelineArg
           { _pipelineArgFile = inputFile,

app/Commands/Dev/Asm/Compile.hs

@@ -30,10 +30,10 @@ runCommand opts = do
           ensureDir buildDir
           cFile <- inputCFile file
           embed $ TIO.writeFile (toFilePath cFile) _resultCCode
-          Compile.runCommand opts {_compileInputFile = AppPath (preFileFromAbs cFile) False}
+          Compile.runCommand opts {_compileInputFile = Just (AppPath (preFileFromAbs cFile) False)}
   where
     getFile :: Sem r (Path Abs File)
-    getFile = fromAppPathFile (opts ^. compileInputFile)
+    getFile = getMainFile (opts ^. compileInputFile)
 
     getTarget :: CompileTarget -> Sem r Backend.Target
     getTarget = \case

app/Commands/Dev/Core/Compile.hs

@@ -21,4 +21,4 @@ runCommand opts = do
     TargetAsm -> runAsmPipeline arg
   where
     getFile :: Sem r (Path Abs File)
-    getFile = fromAppPathFile (opts ^. compileInputFile)
+    getFile = getMainFile (opts ^. compileInputFile)

app/Commands/Dev/Core/Compile/Base.hs

@@ -56,7 +56,7 @@ runCPipeline pa@PipelineArg {..} = do
   outfile <- Compile.outputFile _pipelineArgOptions _pipelineArgFile
   Compile.runCommand
     _pipelineArgOptions
-      { _compileInputFile = AppPath (preFileFromAbs cFile) False,
+      { _compileInputFile = Just (AppPath (preFileFromAbs cFile) False),
         _compileOutputFile = Just (AppPath (preFileFromAbs outfile) False)
       }
   where

app/Commands/Extra/Compile.hs

@@ -10,7 +10,7 @@ import System.Process qualified as P
 
 runCommand :: forall r. (Members '[Embed IO, App] r) => CompileOptions -> Sem r ()
 runCommand opts = do
-  inputFile <- fromAppPathFile (opts ^. compileInputFile)
+  inputFile <- getMainFile (opts ^. compileInputFile)
   result <- runCompile inputFile opts
   case result of
     Left err -> printFailureExit err

app/Commands/Extra/Compile/Options.hs

@@ -30,7 +30,7 @@ data CompileOptions = CompileOptions
     _compileTerm :: Bool,
     _compileOutputFile :: Maybe (AppPath File),
     _compileTarget :: CompileTarget,
-    _compileInputFile :: AppPath File,
+    _compileInputFile :: Maybe (AppPath File),
     _compileOptimizationLevel :: Maybe Int,
     _compileInliningDepth :: Int
   }
@@ -100,7 +100,7 @@ parseCompileOptions supportedTargets parseInputFile = do
       )
   _compileTarget <- optCompileTarget supportedTargets
   _compileOutputFile <- optional parseGenericOutputFile
-  _compileInputFile <- parseInputFile
+  _compileInputFile <- optional parseInputFile
   pure CompileOptions {..}
 
 optCompileTarget :: SupportedTargets -> Parser CompileTarget

app/Commands/Init.hs

@@ -49,6 +49,7 @@ getPackage = do
       { _packageName = tproj,
         _packageVersion = tversion,
         _packageBuildDir = Nothing,
+        _packageMain = Nothing,
         _packageDependencies = [defaultStdlibDep]
       }
 

examples/milestone/Collatz/juvix.yaml

@@ -1,2 +1,3 @@
 name: Collatz
+main: Collatz.juvix
 version: 0.1.0

examples/milestone/Fibonacci/juvix.yaml

@@ -1,2 +1,3 @@
 name: Fibonacci
+main: Fibonacci.juvix
 version: 0.1.0

examples/milestone/Hanoi/juvix.yaml

@@ -1,2 +1,3 @@
 name: Hanoi
+main: Hanoi.juvix
 version: 0.1.0

examples/milestone/HelloWorld/juvix.yaml

@@ -1,2 +1,3 @@
 name: HelloWorld
+main: HelloWorld.juvix
 version: 0.1.0

examples/milestone/PascalsTriangle/juvix.yaml

@@ -1,2 +1,3 @@
 name: PascalsTriangle
+main: PascalsTriangle.juvix
 version: 0.1.0

examples/milestone/TicTacToe/juvix.yaml

@@ -1,2 +1,3 @@
 name: TicTacToe
+main: CLI/TicTacToe.juvix
 version: 0.1.0

src/Juvix/Compiler/Pipeline/Package.hs

@@ -8,6 +8,7 @@ module Juvix.Compiler.Pipeline.Package
     packageBuildDir,
     packageVersion,
     packageDependencies,
+    packageMain,
     rawPackage,
     readPackage,
     readPackageIO,
@@ -49,7 +50,8 @@ data Package' (s :: IsProcessed) = Package
   { _packageName :: NameType s,
     _packageVersion :: VersionType s,
     _packageDependencies :: DependenciesType s,
-    _packageBuildDir :: Maybe (SomeBase Dir)
+    _packageBuildDir :: Maybe (SomeBase Dir),
+    _packageMain :: Maybe (Prepath File)
   }
   deriving stock (Generic)
 
@@ -88,6 +90,7 @@ instance FromJSON RawPackage where
         _packageVersion <- keyMay "version" asText
         _packageDependencies <- keyMay "dependencies" fromAesonParser
         _packageBuildDir <- keyMay "build-dir" fromAesonParser
+        _packageMain <- keyMay "main" fromAesonParser
         return Package {..}
       err :: a
       err = error "Failed to parse juvix.yaml"
@@ -99,6 +102,7 @@ emptyPackage =
     { _packageName = defaultPackageName,
       _packageVersion = defaultVersion,
       _packageDependencies = [defaultStdlibDep],
+      _packageMain = Nothing,
       _packageBuildDir = Nothing
     }
 
@@ -108,7 +112,8 @@ rawPackage pkg =
     { _packageName = Just (pkg ^. packageName),
       _packageVersion = Just (prettySemVer (pkg ^. packageVersion)),
       _packageDependencies = Just (pkg ^. packageDependencies),
-      _packageBuildDir = pkg ^. packageBuildDir
+      _packageBuildDir = pkg ^. packageBuildDir,
+      _packageMain = pkg ^. packageMain
     }
 
 processPackage :: forall r. (Members '[Error Text] r) => Maybe (SomeBase Dir) -> RawPackage -> Sem r Package
@@ -117,9 +122,13 @@ processPackage buildDir pkg = do
       base :: SomeBase Dir = fromMaybe (Rel relBuildDir) buildDir <///> relStdlibDir
       stdlib = Dependency (mkPrepath (fromSomeDir base))
       _packageDependencies = fromMaybe [stdlib] (pkg ^. packageDependencies)
-      _packageBuildDir = pkg ^. packageBuildDir
   _packageVersion <- getVersion
-  return Package {..}
+  return
+    Package
+      { _packageBuildDir = pkg ^. packageBuildDir,
+        _packageMain = pkg ^. packageMain,
+        ..
+      }
   where
     getVersion :: Sem r SemVer
     getVersion = case pkg ^. packageVersion of
@@ -143,6 +152,7 @@ globalPackage =
     { _packageDependencies = [defaultStdlibDep],
       _packageName = "global-juvix-package",
       _packageVersion = defaultVersion,
+      _packageMain = Nothing,
       _packageBuildDir = Nothing
     }
 

src/Juvix/Prelude/Prepath.hs

@@ -20,7 +20,9 @@ import System.Directory qualified as System
 import System.Environment
 
 -- | A file/directory path that may contain environmental variables
-newtype Prepath d = Prepath {_prepath :: String}
+newtype Prepath d = Prepath
+  { _prepath :: String
+  }
   deriving stock (Show, Eq, Data, Generic)
 
 makeLenses ''Prepath

tests/smoke/Commands/compile.smoke.yaml

@@ -11,6 +11,34 @@ tests:
         JUVIX_FILE
     exit-status: 0
 
+  - name: hello-world-no-arg
+    command:
+      shell:
+        - bash
+      script: |
+        cd ./examples/milestone/HelloWorld
+        juvix compile
+        ./HelloWorld
+    exit-status: 0
+    stdout: |
+      hello world!
+
+  - name: hello-world-no-arg-error
+    command:
+      shell:
+        - bash
+      script: |
+        temp=$(mktemp -d)
+        trap 'rm -rf -- "$temp"' EXIT
+        cd ./examples/milestone/
+        cp -r HelloWorld "$temp"
+        cd "$temp/HelloWorld"
+        sed -i '/^main:/d' juvix.yaml
+        juvix compile
+    exit-status: 1
+    stdout: |
+     A path to the main file must be given in the CLI or specified in the `main` field of the juvix.yaml file
+
   - name: hello-world
     command:
       shell: