Refactor argument handling

Move input-independent arguments to a top-level product type rather than duplicating them in `FileArgs` and `StdinArgs`. Without this, specifying `--verbose` before `-i` would lock-in `StdinInput` alternative. The arguments would also be duplicated in the help page.
nix-community · May 19, 2024 · 664d51e · 664d51e
1 parent 3176945
commit 664d51e
Show file tree

Hide file tree

Showing 3 changed files with 21 additions and 25 deletions.
diff --git a/README.md b/README.md
@@ -105,9 +105,9 @@ Type `--help` for some more information.
 ```shell
 dconf2nix - Nixify dconf configuration files
 
-Usage: dconf2nix [-v|--version] 
-                 [[-r|--root ARG] [--verbose] | (-i|--input ARG)
-                   (-o|--output ARG) [-r|--root ARG] [--verbose]]
+Usage: dconf2nix [-v|--version] [-r|--root ARG] [--verbose]
+                 [(-i|--input ARG) (-o|--output ARG)]
+
   Convert a dconf file into a Nix file, as expected by Home Manager.
 
 Available options:
@@ -117,8 +117,6 @@ Available options:
   --verbose                Verbose mode (debug)
   -i,--input ARG           Path to the dconf file (input)
   -o,--output ARG          Path to the Nix output file (to be created)
-  -r,--root ARG            Custom root path. e.g.: system/locale/
-  --verbose                Verbose mode (debug)
 ```
 
 #### Custom root

diff --git a/app/Main.hs b/app/Main.hs
@@ -2,9 +2,9 @@
 
 module Main where
 
-import           CommandLine                    ( FileArgs(..)
+import           CommandLine                    ( Args(..)
+                                                , FileArgs(..)
                                                 , Input(..)
-                                                , StdinArgs(..)
                                                 , runArgs
                                                 )
 import           DConf2Nix                      ( dconf2nixFile
@@ -13,7 +13,7 @@ import           DConf2Nix                      ( dconf2nixFile
 
 main :: IO ()
 main = runArgs >>= \case
-  FileInput (FileArgs i o r v) ->
+  Args r v (FileInput (FileArgs i o)) ->
     dconf2nixFile i o r v
-  StdinInput (StdinArgs r v)   ->
+  Args r v StdinInput   ->
     dconf2nixStdin r v
diff --git a/src/CommandLine.hs b/src/CommandLine.hs
@@ -1,7 +1,7 @@
 module CommandLine
-  ( FileArgs(..)
+  ( Args(..)
+  , FileArgs(..)
   , Input(..)
-  , StdinArgs(..)
   , runArgs
   )
 where
@@ -12,18 +12,17 @@ import           DConf.Data
 import           Options.Applicative
 import           Paths_dconf2nix                ( version )
 
-data Input = FileInput FileArgs | StdinInput StdinArgs
+data Args = Args
+  { argsRoot :: Root
+  , argsVerbosity :: Verbosity
+  , argsInput :: Input
+  }
+
+data Input = FileInput FileArgs | StdinInput
 
 data FileArgs = FileArgs
   { fileInput :: InputFilePath
   , fileOutput :: OutputFilePath
-  , fileRoot :: Root
-  , fileVerbosity :: Verbosity
-  }
-
-data StdinArgs = StdinArgs
-  { stdinRoot :: Root
-  , stdinVerbosity :: Verbosity
   }
 
 verbosityArgs :: Parser Verbosity
@@ -46,12 +45,9 @@ fileArgs = fmap FileInput $ FileArgs
             "Path to the Nix output file (to be created)"
           )
         )
-    <*> rootArgs
-    <*> verbosityArgs
 
 stdinArgs :: Parser Input
-stdinArgs =
-  StdinInput <$> (StdinArgs <$> rootArgs <*> verbosityArgs)
+stdinArgs = pure StdinInput
 
 versionInfo :: String
 versionInfo = unlines
@@ -72,11 +68,13 @@ versionOpt :: Parser (a -> a)
 versionOpt = infoOption versionInfo
   (long "version" <> short 'v' <> help "Show the current version")
 
-runArgs :: IO Input
+runArgs :: IO Args
 runArgs =
   let
+    args = Args <$> rootArgs <*> verbosityArgs <*> (stdinArgs <|> fileArgs)
+
     opts = info
-      (helper <*> versionOpt <*> (stdinArgs <|> fileArgs))
+      (helper <*> versionOpt <*> args)
       (  fullDesc
       <> progDesc
            "Convert a dconf file into a Nix file, as expected by Home Manager."