[#6] Implement version parsers (#18)

Resolves #6

app/Main.hs

@@ -3,6 +3,7 @@ module Main (main) where
 import Control.Monad.IO.Class (MonadIO (..))
 
 import qualified Iris
+import qualified Paths_iris as Autogen
 
 
 newtype App a = App
@@ -11,8 +12,12 @@ newtype App a = App
 
 appSettings :: Iris.CliEnvSettings () ()
 appSettings = Iris.defaultCliEnvSettings
-    { Iris.cliEnvSettingsHeaderDesc = "Iris usage example"
-    , Iris.cliEnvSettingsProgDesc   = "A simple grep utility"
+    { Iris.cliEnvSettingsHeaderDesc      = "Iris usage example"
+    , Iris.cliEnvSettingsProgDesc        = "A simple grep utility"
+    , Iris.cliEnvSettingsVersionSettings =
+        Just (Iris.defaultVersionSettings Autogen.version)
+            { Iris.versionSettingsMkDesc = \v -> "Iris Example v" <> v
+            }
     }
 
 app :: App ()

iris.cabal

@@ -76,7 +76,11 @@ library
 executable iris-example
   import:              common-options
   hs-source-dirs:      app
+
   main-is:             Main.hs
+  autogen-modules:     Paths_iris
+  other-modules:       Paths_iris
+
   build-depends:       iris
   ghc-options:         -threaded
                        -rtsopts

src/Iris/Env.hs

@@ -13,67 +13,99 @@ Environment of a CLI app.
 
 
 module Iris.Env
-    ( -- * CLI application environment
-      CliEnv (..)
-
-      -- * Settings for the CLI app
-    , CliEnvSettings (..)
+    ( -- * Settings for the CLI app
+      -- ** Global CLI settings
+      CliEnvSettings (..)
     , defaultCliEnvSettings
+      -- ** Application version settings
+    , VersionSettings (..)
+    , defaultVersionSettings
+
+      -- * CLI application environment
+    , CliEnv (..)
     , mkCliEnv
     ) where
 
 import Data.Kind (Type)
+import Data.Version (Version, showVersion)
 
 import qualified Options.Applicative as Opt
 
 
-{- | CLI application environment. It contains default settings for
-every CLI app and parameter
-
-Has the following type parameters:
-
-* @cmd@ — application commands
-* @appEnv@ — application-specific environment; use @()@ if you don't
-  have custom app environment
+{- |
 
 @since 0.0.0.0
 -}
-data CliEnv (cmd :: Type) (appEnv :: Type) = CliEnv
-    { -- | @since 0.0.0.0
-      cliEnvCmd    :: cmd
+data CliEnvSettings (cmd :: Type) (appEnv :: Type) = CliEnvSettings
+    {  -- | @since 0.0.0.0
+      cliEnvSettingsCmdParser       :: Opt.Parser cmd
 
       -- | @since 0.0.0.0
-    , cliEnvAppEnv :: appEnv
+    , cliEnvSettingsAppEnv          :: appEnv
+
+      -- | @since 0.0.0.0
+    , cliEnvSettingsHeaderDesc      :: String
+
+      -- | @since 0.0.0.0
+    , cliEnvSettingsProgDesc        :: String
+
+      -- | @since 0.0.0.0
+    , cliEnvSettingsVersionSettings :: Maybe VersionSettings
     }
 
+
 {- |
 
 @since 0.0.0.0
 -}
-data CliEnvSettings (cmd :: Type) (appEnv :: Type) = CliEnvSettings
-    {  -- | @since 0.0.0.0
-      cliEnvSettingsCmdParser  :: Opt.Parser cmd
+defaultCliEnvSettings :: CliEnvSettings () ()
+defaultCliEnvSettings = CliEnvSettings
+    { cliEnvSettingsCmdParser       = pure ()
+    , cliEnvSettingsAppEnv          = ()
+    , cliEnvSettingsHeaderDesc      = "Simple CLI program"
+    , cliEnvSettingsProgDesc        = "CLI tool build with iris - a Haskell CLI framework"
+    , cliEnvSettingsVersionSettings = Nothing
+    }
 
-      -- | @since 0.0.0.0
-    , cliEnvSettingsAppEnv     :: appEnv
+{- |
 
-      -- | @since 0.0.0.0
-    , cliEnvSettingsHeaderDesc :: String
+@since 0.0.0.0
+-}
+data VersionSettings = VersionSettings
+    { -- | @since 0.0.0.0
+      versionSettingsVersion :: Version
 
       -- | @since 0.0.0.0
-    , cliEnvSettingsProgDesc   :: String
+    , versionSettingsMkDesc  :: String -> String
     }
 
 {- |
 
 @since 0.0.0.0
 -}
-defaultCliEnvSettings :: CliEnvSettings () ()
-defaultCliEnvSettings = CliEnvSettings
-    { cliEnvSettingsCmdParser   = pure ()
-    , cliEnvSettingsAppEnv      = ()
-    , cliEnvSettingsHeaderDesc  = "Simple CLI program"
-    , cliEnvSettingsProgDesc    = "CLI tool build with iris - a Haskell CLI framework"
+defaultVersionSettings :: Version -> VersionSettings
+defaultVersionSettings version = VersionSettings
+    { versionSettingsVersion = version
+    , versionSettingsMkDesc  = id
+    }
+
+{- | CLI application environment. It contains default settings for
+every CLI app and parameter
+
+Has the following type parameters:
+
+* @cmd@ — application commands
+* @appEnv@ — application-specific environment; use @()@ if you don't
+  have custom app environment
+
+@since 0.0.0.0
+-}
+data CliEnv (cmd :: Type) (appEnv :: Type) = CliEnv
+    { -- | @since 0.0.0.0
+      cliEnvCmd    :: cmd
+
+      -- | @since 0.0.0.0
+    , cliEnvAppEnv :: appEnv
     }
 
 {- |
@@ -92,8 +124,34 @@ mkCliEnv CliEnvSettings{..} = do
         }
   where
     cmdParserInfo :: Opt.ParserInfo cmd
-    cmdParserInfo = Opt.info (Opt.helper <*> cliEnvSettingsCmdParser) $ mconcat
-        [ Opt.fullDesc
-        , Opt.header cliEnvSettingsHeaderDesc
-        , Opt.progDesc cliEnvSettingsProgDesc
-        ]
+    cmdParserInfo = Opt.info
+        ( Opt.helper
+        <*> mkVersionParser cliEnvSettingsVersionSettings
+        <*> cliEnvSettingsCmdParser
+        )
+        $ mconcat
+            [ Opt.fullDesc
+            , Opt.header cliEnvSettingsHeaderDesc
+            , Opt.progDesc cliEnvSettingsProgDesc
+            ]
+
+mkVersionParser :: Maybe VersionSettings -> Opt.Parser (a -> a)
+mkVersionParser = maybe (pure id) fullVersionP
+
+fullVersionP :: VersionSettings -> Opt.Parser (a -> a)
+fullVersionP VersionSettings{..} = versionP <*> numericVersionP
+  where
+    versionStr :: String
+    versionStr = showVersion versionSettingsVersion
+
+    versionP :: Opt.Parser (a -> a)
+    versionP = Opt.infoOption (versionSettingsMkDesc versionStr) $ mconcat
+       [ Opt.long "version"
+       , Opt.help "Show application version"
+       ]
+
+    numericVersionP :: Opt.Parser (a -> a)
+    numericVersionP = Opt.infoOption versionStr $ mconcat
+       [ Opt.long "numeric-version"
+       , Opt.help "Show only numeric application version"
+       ]