resolve #107 IO module out outLn etc

CHANGELOG.md

@@ -11,6 +11,14 @@ available [on GitHub][2].
 <!-- Add new changes here -->
 
 ### Added 
+
+[#107] (https://github.com/chshersh/iris/issues/107):
+Implement 'out', 'outLn', 'err' and 'errLn' functions for outputting 'Text' to corresponding handlers
+
+  * Add `out`, `outLn`, `err` and `errLn` functions for outputting 'Text' to corresponding handlers
+
+  (by [@martinhelmer])
+
 [#9](https://github.com/chshersh/iris/issues/9):
 Implement Yes/No reading functions:
 

iris.cabal

@@ -96,6 +96,7 @@ library
       Iris.Tool
       Iris.Interactive 
         Iris.Interactive.Question 
+      Iris.IO
 
 
   build-depends:
@@ -126,13 +127,15 @@ test-suite iris-test
       Test.Iris.Tool
       Test.Iris.Interactive
         Test.Iris.Interactive.Question
+      Test.Iris.IO
 
   build-depends:
     , iris
     , hspec >= 2.9.7 && < 2.11
     , text
     , optparse-applicative
-
+    , silently 
+
   ghc-options:
     -threaded
     -rtsopts

src/Iris.hs

@@ -49,13 +49,16 @@ module Iris (
     -- $tool
     module Iris.Tool,
     module Iris.Interactive,
+    module Iris.IO,
+    -- $io
 ) where
 
 import Iris.App
 import Iris.Browse
 import Iris.Cli
 import Iris.Colour
 import Iris.Env
+import Iris.IO
 import Iris.Interactive
 import Iris.Settings
 import Iris.Tool
@@ -80,6 +83,10 @@ Functions to detect terminal support for colouring and print coloured output.
 Global environment for a CLI application and CLI app settings.
 -}
 
+{- $io
+Output Text to stdout/ stderr
+-}
+
 {- $settings
 Settings for the environment.
 -}

src/Iris/Colour/Formatting.hs

@@ -22,13 +22,10 @@ module Iris.Colour.Formatting (
 import Control.Monad.IO.Class (MonadIO (..))
 import Control.Monad.Reader (MonadReader)
 import Data.Text (Text)
-import qualified Data.Text.IO as T
-import System.IO (stderr)
 
 import Iris.Colour.Mode (ColourMode (..))
 import Iris.Env (CliEnv (..), asksCliEnv)
-
-import qualified Data.Text.IO as TIO
+import qualified Iris.IO as IO
 
 {- | Print 'Text' to 'System.IO.stdout' by providing a custom
 formatting function.
@@ -52,7 +49,7 @@ putStdoutColouredLn
     -> m ()
 putStdoutColouredLn formatWithColour str = do
     colourMode <- asksCliEnv cliEnvStdoutColourMode
-    liftIO $ T.putStrLn $ case colourMode of
+    liftIO $ IO.outLn $ case colourMode of
         DisableColour -> str
         EnableColour -> formatWithColour str
 
@@ -78,7 +75,7 @@ putStderrColouredLn
     -> m ()
 putStderrColouredLn formatWithColour str = do
     colourMode <- asksCliEnv cliEnvStderrColourMode
-    liftIO $ T.hPutStrLn stderr $ case colourMode of
+    liftIO $ IO.errLn $ case colourMode of
         DisableColour -> str
         EnableColour -> formatWithColour str
 
@@ -105,7 +102,7 @@ putStdoutColoured
     -> m ()
 putStdoutColoured formatWithColour str = do
     colourMode <- asksCliEnv cliEnvStdoutColourMode
-    liftIO $ TIO.putStr $ case colourMode of
+    liftIO $ IO.out $ case colourMode of
         DisableColour -> str
         EnableColour -> formatWithColour str
 
@@ -132,6 +129,6 @@ putStderrColoured
     -> m ()
 putStderrColoured formatWithColour str = do
     colourMode <- asksCliEnv cliEnvStderrColourMode
-    liftIO $ TIO.hPutStr stderr $ case colourMode of
+    liftIO $ IO.err $ case colourMode of
         DisableColour -> str
         EnableColour -> formatWithColour str

src/Iris/IO.hs

@@ -0,0 +1,95 @@
+{- |
+Module                  : Iris.IO
+Copyright               : (c) 2022 Dmitrii Kovanikov
+SPDX-License-Identifier : MPL-2.0
+Maintainer              : Dmitrii Kovanikov <[email protected]>
+Stability               : Experimental
+Portability             : Portable
+
+Functions for IO, such as writing Text to stdout and stderr.
+
+
+Usage example:
+
+@
+import qualified Iris
+
+main = do
+    Iris.outLn "This goes to stdout"
+    Iris.errLn "This goes to stderr"
+@
+
+Results in:
+
+@
+\$ ./app
+This goes to stdout
+This goes to stderr
+@
+
+@since x.x.x.x
+-}
+module Iris.IO (
+    out,
+    outLn,
+    err,
+    errLn,
+) where
+
+import Data.Text (Text)
+import qualified Data.Text.IO as Text
+import System.IO (stderr, stdout)
+
+{- | Write the given Text to stdout.
+No linefeed at the end.
+
+@
+ghci> do Iris.out "foo" >> Iris.out "bar"
+foobarghci>
+
+@
+@since x.x.x.x
+-}
+out :: Text -> IO ()
+out = Text.hPutStr stdout
+
+{- | Write the given Text to stdout with linefeed at the end.
+
+@
+ghci> Iris.outLn "foo" >> Iris.outLn "bar"
+foo
+bar
+ghci>
+
+@
+@since x.x.x.x
+-}
+outLn :: Text -> IO ()
+outLn = Text.hPutStrLn stdout
+
+{- | Write the given Text to stderr.
+No linefeed at the end.
+
+@
+ghci> Iris.err "foo" >> Iris.err "bar"
+foobarghci>
+
+@
+@since x.x.x.x
+-}
+err :: Text -> IO ()
+err = Text.hPutStr stderr
+
+{- | Write the given Text to stderr with linefeed at the end.
+
+@
+ghci> Iris.errLn "foo" >> Iris.errLn "bar"
+foo
+bar
+ghci>
+
+@
+@since x.x.x.x
+-}
+errLn :: Text -> IO ()
+errLn = Text.hPutStrLn stderr

src/Iris/Interactive/Question.hs

@@ -28,6 +28,7 @@ import System.IO (hFlush, stdout)
 
 import Iris.Cli.Interactive (InteractiveMode (..))
 import Iris.Env (CliEnv (..), asksCliEnv)
+import qualified Iris.IO as IO
 
 {-
 @since x.x.x.x
@@ -107,12 +108,12 @@ yesno question defaultAnswer = do
   where
     loop :: IO YesNo
     loop = do
-        Text.putStr $ question <> " (yes/no) "
+        IO.out $ question <> " (yes/no) "
         hFlush stdout
         input <- Text.getLine
         case parseYesNo input of
             Just answer -> pure answer
             Nothing -> do
-                Text.putStrLn $ "I don't understand your answer: '" <> input <> "'"
-                Text.putStrLn "Please, answer yes or no (or y, or n)"
+                IO.out $ "I don't understand your answer: '" <> input <> "'"
+                IO.out "Please, answer yes or no (or y, or n)"
                 loop

test/Test/Iris.hs

@@ -4,6 +4,7 @@ import Test.Hspec (Spec, describe)
 
 import Test.Iris.Cli (cliSpec, cliSpecParserConflicts)
 import Test.Iris.Colour (colourSpec)
+import Test.Iris.IO (ioSpec)
 import Test.Iris.Interactive (interactiveSpec)
 import Test.Iris.Tool (toolSpec)
 
@@ -14,3 +15,4 @@ irisSpec = describe "Iris" $ do
     colourSpec
     toolSpec
     interactiveSpec
+    ioSpec

test/Test/Iris/IO.hs

@@ -0,0 +1,34 @@
+module Test.Iris.IO (ioSpec)
+where
+
+import Test.Hspec (Spec, describe, it, shouldBe)
+
+-- Silently has side effect: writes file to tmp (or current dir) and then deletes it.
+
+import System.IO (stderr, stdout)
+import System.IO.Silently (hCapture_, hSilence)
+
+import qualified Iris.IO as IO (err, errLn, out, outLn)
+
+checkStdErr :: IO a -> IO String
+checkStdErr = hCapture_ [stderr] . hSilence [stdout]
+
+checkStdOut :: IO a -> IO String
+checkStdOut = hCapture_ [stdout] . hSilence [stderr]
+
+ioSpec :: Spec
+ioSpec =
+    describe "IO" $ do
+        describe "out" $ do
+            -- we need `flip` to get the expectation reported correctly in case of a failure
+            it "writes to stdout, no LF " $ checkStdOut (IO.out "TEXT") >>= flip shouldBe "TEXT"
+            it "does not write to stderr " $ checkStdErr (IO.out "TEXT") >>= flip shouldBe ""
+        describe "outLn" $ do
+            it "writes to stdout, LF " $ checkStdOut (IO.outLn "TEXT") >>= flip shouldBe "TEXT\n"
+            it "does not write to stderr " $ checkStdErr (IO.outLn "TEXT") >>= flip shouldBe ""
+        describe "err" $ do
+            it "writes to sterr, no LF " $ checkStdErr (IO.err "TEXT") >>= flip shouldBe "TEXT"
+            it "does not write to stdout " $ checkStdOut (IO.err "TEXT") >>= flip shouldBe ""
+        describe "errLn" $ do
+            it "writes to stderr, LF " $ checkStdErr (IO.errLn "TEXT") >>= flip shouldBe "TEXT\n"
+            it "does not write to stdout " $ checkStdOut (IO.errLn "TEXT") >>= flip shouldBe ""