Recreate stdlib dir only when juvix version changes

src/Juvix/Compiler/Pipeline/Setup.hs

@@ -1,9 +1,9 @@
 module Juvix.Compiler.Pipeline.Setup where
 
 import Juvix.Compiler.Pipeline.EntryPoint
-import Juvix.Prelude
 import Juvix.Extra.Paths
 import Juvix.Extra.Stdlib
+import Juvix.Prelude
 
 entrySetup ::
   Members '[Embed IO, Reader EntryPoint, Files] r =>
@@ -21,7 +21,7 @@ setupStdlib = do
   stdlibRootPath <- case e ^. entryPointStdlibPath of
     Nothing -> do
       let d = (e ^. entryPointRoot) </> juvixStdlibDir
-      updateStdlib d
+      runReader d updateStdlib
       return d
     Just p -> return p
   registerStdlib stdlibRootPath

src/Juvix/Extra/Stdlib.hs

@@ -2,19 +2,48 @@ module Juvix.Extra.Stdlib where
 
 import Data.ByteString qualified as BS
 import Juvix.Extra.Paths
+import Juvix.Extra.Version
 import Juvix.Prelude
 
+type RootPath = FilePath
+
 stdlibFiles :: [(FilePath, ByteString)]
 stdlibFiles = filter isJuvixFile $(stdlibDir)
   where
     isJuvixFile :: (FilePath, ByteString) -> Bool
     isJuvixFile (fp, _) = takeExtension fp == ".juvix"
 
-writeStdlib :: forall r. Member (Embed IO) r => FilePath -> Sem r ()
-writeStdlib rootDir = forM_ (first (rootDir </>) <$> stdlibFiles) (uncurry writeJuvixFile)
+writeStdlib :: forall r. Members '[Reader RootPath, Embed IO] r => Sem r ()
+writeStdlib = do
+  rootDir <- ask
+  forM_ (first (rootDir </>) <$> stdlibFiles) (uncurry writeJuvixFile)
   where
     writeJuvixFile :: FilePath -> ByteString -> Sem r ()
     writeJuvixFile p bs = embed (createDirectoryIfMissing True (takeDirectory p) >> BS.writeFile p bs)
 
-updateStdlib :: forall r. Member (Embed IO) r => FilePath -> Sem r ()
-updateStdlib rootDir = unlessM (embed (doesDirectoryExist rootDir)) (writeStdlib rootDir)
+stdlibVersionFile :: Member (Reader RootPath) r => Sem r FilePath
+stdlibVersionFile = (</> ".version") <$> ask
+
+writeVersion :: forall r. Members '[Reader RootPath, Embed IO] r => Sem r ()
+writeVersion = (embed . flip writeFile versionTag) =<< stdlibVersionFile
+
+readVersion :: Members '[Reader RootPath, Embed IO] r => Sem r (Maybe Text)
+readVersion = do
+  vf <- stdlibVersionFile
+  embed (whenMaybeM (doesFileExist vf) (readFile vf))
+
+updateStdlib :: forall r. Members '[Reader RootPath, Embed IO] r => Sem r ()
+updateStdlib =
+  whenM shouldUpdate $ do
+    whenM
+      (embed . doesDirectoryExist =<< ask)
+      (embed . removeDirectoryRecursive =<< ask)
+    writeStdlib
+    writeVersion
+  where
+    shouldUpdate :: Sem r Bool
+    shouldUpdate =
+      orM
+        [ not <$> (embed . doesDirectoryExist =<< ask),
+          (Just versionTag /=) <$> readVersion
+        ]

src/Juvix/Prelude/Base.hs

@@ -133,6 +133,8 @@ import GHC.Real
 import GHC.Stack.Types
 import Language.Haskell.TH.Syntax (Lift)
 import Lens.Micro.Platform hiding (both)
+import Path (parseAbsDir, toFilePath)
+import Path.IO (listDirRecur)
 import Polysemy
 import Polysemy.Embed
 import Polysemy.Error hiding (fromEither)
@@ -163,8 +165,6 @@ import System.IO hiding
   )
 import Text.Show (Show)
 import Text.Show qualified as Show
-import Path.IO (listDirRecur)
-import Path (parseAbsDir, toFilePath)
 
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