Merge pull request #7 from haskell-works/newhoggy/new-ToString-typeclass

Adopt some useful modules from `hw-polysemy`

hw-prelude.cabal

@@ -94,11 +94,15 @@ library
                         HaskellWorks.Error.Types
                         HaskellWorks.Error.Types.GenericError
                         HaskellWorks.Error.Types.TimedOut
+                        HaskellWorks.FilePath
                         HaskellWorks.IO.Network.NamedPipe
                         HaskellWorks.IO.Network.Port
                         HaskellWorks.IO.Network.Socket
                         HaskellWorks.IO.Process
+                        HaskellWorks.OS
                         HaskellWorks.Prelude
+                        HaskellWorks.Stack
+                        HaskellWorks.String
                         HaskellWorks.ToText
                         HaskellWorks.Unsafe
   hs-source-dirs:       src

src/HaskellWorks/FilePath.hs

@@ -0,0 +1,18 @@
+module HaskellWorks.FilePath
+  ( exeSuffix,
+    addExeSuffix,
+  ) where
+
+import qualified HaskellWorks.OS as OS
+
+import qualified Data.List       as L
+import           Data.Monoid
+import           Data.String
+
+exeSuffix :: String
+exeSuffix = if OS.isWin32 then ".exe" else ""
+
+addExeSuffix :: String -> String
+addExeSuffix s = if ".exe" `L.isSuffixOf` s
+  then s
+  else s <> exeSuffix

src/HaskellWorks/OS.hs

@@ -0,0 +1,12 @@
+module HaskellWorks.OS
+  ( isWin32,
+  ) where
+
+import           Data.Bool
+import           Data.Eq
+import           System.Info
+
+-- | Determine if the operating system is Windows.
+isWin32 :: Bool
+isWin32 = os == "mingw32"
+{-# INLINE isWin32 #-}

src/HaskellWorks/Stack.hs

@@ -0,0 +1,14 @@
+module HaskellWorks.Stack
+  ( callerModuleName,
+  ) where
+
+import           Data.Function
+import           Data.Maybe    (listToMaybe, maybe)
+import           Data.String
+import           Data.Tuple
+import           GHC.Stack     (HasCallStack, callStack, getCallStack,
+                                srcLocModule)
+
+-- | Get the module name of the caller.
+callerModuleName :: HasCallStack => String
+callerModuleName = maybe "<no-module>" (srcLocModule . snd) (listToMaybe (getCallStack callStack))

src/HaskellWorks/String.hs

@@ -0,0 +1,21 @@
+module HaskellWorks.String
+  ( ToString(..),
+  ) where
+
+import           Data.Function
+import           Data.String
+import           Data.Text      (Text)
+import qualified Data.Text      as T
+import qualified Data.Text.Lazy as LT
+
+class ToString a where
+  toString :: a -> String
+
+instance ToString String where
+  toString = id
+
+instance ToString Text where
+  toString = T.unpack
+
+instance ToString LT.Text where
+  toString = LT.unpack