aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/bin/Prompt.hs
diff options
context:
space:
mode:
authorEgor Tensin <Egor.Tensin@gmail.com>2017-03-25 05:56:02 +0300
committerEgor Tensin <Egor.Tensin@gmail.com>2017-03-25 05:56:02 +0300
commit80f6847645459dfd21e531946e1eeaf2384a2dff (patch)
tree8a93e818fe647974bd724be08092e9475d03425f /bin/Prompt.hs
parentadd README to the package (diff)
downloadwindows-env-80f6847645459dfd21e531946e1eeaf2384a2dff.tar.gz
windows-env-80f6847645459dfd21e531946e1eeaf2384a2dff.zip
rename directories
Diffstat (limited to 'bin/Prompt.hs')
-rw-r--r--bin/Prompt.hs50
1 files changed, 50 insertions, 0 deletions
diff --git a/bin/Prompt.hs b/bin/Prompt.hs
new file mode 100644
index 0000000..404c582
--- /dev/null
+++ b/bin/Prompt.hs
@@ -0,0 +1,50 @@
+-- |
+-- Copyright : (c) 2015 Egor Tensin <Egor.Tensin@gmail.com>
+-- License : MIT
+-- Maintainer : Egor.Tensin@gmail.com
+-- Stability : experimental
+-- Portability : portable
+
+module Prompt
+ ( withPrompt
+ , withoutPrompt
+ ) where
+
+import Control.Monad (void, when)
+import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Except (ExceptT)
+import Data.Char (toLower)
+import System.IO (hFlush, stdout)
+
+prompt :: String -> IO String
+prompt msg = do
+ putStr msg
+ hFlush stdout
+ getLine
+
+promptYesNo :: String -> IO Bool
+promptYesNo msg = do
+ response <- map toLower <$> prompt msg
+ if response `elem` yeses
+ then return True
+ else if response `elem` noes
+ then return False
+ else promptToContinue
+ where
+ yeses = ["y", "yes"]
+ noes = ["n", "no"]
+
+promptToContinue :: IO Bool
+promptToContinue = promptYesNo "Continue? (y/n) "
+
+withPrompt :: String -> ExceptT IOError IO a -> ExceptT IOError IO Bool
+withPrompt msg m = do
+ lift $ do
+ putStr msg
+ hFlush stdout
+ agreed <- lift promptToContinue
+ when agreed $ void m
+ return agreed
+
+withoutPrompt :: ExceptT IOError IO a -> ExceptT IOError IO Bool
+withoutPrompt m = m >> return True