Reset cursor position on rebuild with --clear-screen --watch (purescr…

…ipt#466)

CHANGELOG.md

@@ -29,6 +29,7 @@ Bugfixes:
 - Fix confusing warning when trying to `spago install` a package already present in project dependencies list (#436)
 - Do not watch files in `.spago` folder when running `spago build --watch` (#430)
 - Fix dynamic libraries compatibility problems by publishing a statically linked executable for Linux (#427, #437)
+- `--clear-screen` (usable e.g. with `spago build --watch`) now also resets cursor position, so the rebuild message always appears at top left of the screen (#465)
 
 Other improvements:
 - Speed up test suite by replacing couple of end 2 end bump-version tests with unit/property tests

src/Spago/Watch.hs

@@ -10,16 +10,16 @@ import Control.Concurrent.STM (check)
 import qualified Data.Map.Strict as Map
 import qualified Data.Set as Set
 import Data.Text (pack, toLower, unpack)
+import Data.Time.Clock (NominalDiffTime, diffUTCTime, getCurrentTime)
 import GHC.IO (FilePath)
 import GHC.IO.Exception
-import System.Console.ANSI (clearScreen)
+import System.Console.ANSI (clearScreen, setCursorPosition)
 import System.FilePath (splitDirectories)
 import qualified System.FilePath.Glob as Glob
 import qualified System.FSNotify as Watch
 import System.IO (getLine)
 import qualified UnliftIO
 import UnliftIO.Async (race_)
-import Data.Time.Clock (NominalDiffTime, getCurrentTime, diffUTCTime)
 
 -- Should we clear the screen on rebuild?
 data ClearScreen = DoClear | NoClear
@@ -65,7 +65,9 @@ fileWatchConf watchConfig shouldClear inner = withManagerConf watchConfig $ \man
  watchVar <- liftIO $ newTVarIO Map.empty
 
  let redisplay maybeMsg = do
- when (shouldClear == DoClear) $ liftIO clearScreen
+ when (shouldClear == DoClear) $ liftIO $ do
+ clearScreen
+ setCursorPosition 0 0
  mapM_ echoStr maybeMsg
 
  let onChange event = do