7 files changed, 126 insertions, 8 deletions
diff --git a/tv/5pkgs/haskell/th-env/default.nix b/tv/5pkgs/haskell/th-env/default.nix
new file mode 100644
index 00000000..474a63b8
--- /dev/null
+++ b/tv/5pkgs/haskell/th-env/default.nix
@@ -0,0 +1,10 @@
+{ mkDerivation, base, stdenv, template-haskell, text }:
+mkDerivation {
+  pname = "th-env";
+  version = "1.0.0";
+  src = ./.;
+  libraryHaskellDepends = [ base template-haskell text ];
+  homepage = "https://stackoverflow.com/q/57635686";
+  license = "unknown";
+  hydraPlatforms = stdenv.lib.platforms.none;
+}
diff --git a/tv/5pkgs/haskell/th-env/src/THEnv.hs b/tv/5pkgs/haskell/th-env/src/THEnv.hs
new file mode 100644
index 00000000..b04f2ce0
--- /dev/null
+++ b/tv/5pkgs/haskell/th-env/src/THEnv.hs
@@ -0,0 +1,49 @@
+{-# LANGUAGE TemplateHaskell #-}
+module THEnv
+    (
+    -- * Compile-time configuration
+      lookupCompileEnv
+    , lookupCompileEnvExp
+    , getCompileEnv
+    , getCompileEnvExp
+    , fileAsString
+    ) where
+
+import Control.Monad
+import qualified Data.Text as T
+import qualified Data.Text.IO as T
+import Language.Haskell.TH
+import Language.Haskell.TH.Syntax (Lift(..))
+import System.Environment (getEnvironment)
+
+-- Functions that work with compile-time configuration
+
+-- | Looks up a compile-time environment variable.
+lookupCompileEnv :: String -> Q (Maybe String)
+lookupCompileEnv key = lookup key `liftM` runIO getEnvironment
+
+-- | Looks up a compile-time environment variable. The result is a TH
+-- expression of type @Maybe String@.
+lookupCompileEnvExp :: String -> Q Exp
+lookupCompileEnvExp = (`sigE` [t| Maybe String |]) . lift <=< lookupCompileEnv
+    -- We need to explicly type the result so that things like `print Nothing`
+    -- work.
+
+-- | Looks up an compile-time environment variable and fail, if it's not
+-- present.
+getCompileEnv :: String -> Q String
+getCompileEnv key =
+  lookupCompileEnv key >>=
+  maybe (fail $ "Environment variable " ++ key ++ " not defined") return
+
+-- | Looks up an compile-time environment variable and fail, if it's not
+-- present. The result is a TH expression of type @String@.
+getCompileEnvExp :: String -> Q Exp
+getCompileEnvExp = lift <=< getCompileEnv
+
+-- | Loads the content of a file as a string constant expression.
+-- The given path is relative to the source directory.
+fileAsString :: FilePath -> Q Exp
+fileAsString = do
+  -- addDependentFile path -- works only with template-haskell >= 2.7
+  stringE . T.unpack . T.strip <=< runIO . T.readFile
diff --git a/tv/5pkgs/haskell/th-env/th-env.cabal b/tv/5pkgs/haskell/th-env/th-env.cabal
new file mode 100644
index 00000000..b9a2cff3
--- /dev/null
+++ b/tv/5pkgs/haskell/th-env/th-env.cabal
@@ -0,0 +1,20 @@
+name: th-env
+version: 1.0.0
+-- license: https://creativecommons.org/licenses/by-sa/4.0/
+license: OtherLicense
+author: https://stackoverflow.com/users/9348482
+homepage: https://stackoverflow.com/q/57635686
+maintainer: tv <tv@krebsco.de>
+build-type: Simple
+cabal-version: >=1.10
+
+library
+  hs-source-dirs: src
+  build-depends:
+    base,
+    template-haskell,
+    text
+  exposed-modules:
+    THEnv
+  default-language: Haskell2010
+  ghc-options: -O2 -Wall
diff --git a/tv/5pkgs/haskell/xmonad-tv/default.nix b/tv/5pkgs/haskell/xmonad-tv/default.nix
index 42eb13d4..36dffaa1 100644
--- a/tv/5pkgs/haskell/xmonad-tv/default.nix
+++ b/tv/5pkgs/haskell/xmonad-tv/default.nix
@@ -1,5 +1,6 @@
-{ mkDerivation, base, containers, directory, extra, stdenv, unix
-, X11, xmonad, xmonad-contrib, xmonad-stockholm
+{ mkDerivation, aeson, base, bytestring, containers, directory
+, extra, stdenv, template-haskell, th-env, unix, X11, xmonad
+, xmonad-contrib, xmonad-stockholm
 }:
 mkDerivation {
   pname = "xmonad-tv";
@@ -8,8 +9,8 @@ mkDerivation {
   isLibrary = false;
   isExecutable = true;
   executableHaskellDepends = [
-    base containers directory extra unix X11 xmonad xmonad-contrib
-    xmonad-stockholm
+    aeson base bytestring containers directory extra template-haskell
+    th-env unix X11 xmonad xmonad-contrib xmonad-stockholm
   ];
   license = stdenv.lib.licenses.mit;
 }
diff --git a/tv/5pkgs/haskell/xmonad-tv/src/THEnv/JSON.hs b/tv/5pkgs/haskell/xmonad-tv/src/THEnv/JSON.hs
new file mode 100644
index 00000000..2a3a0e52
--- /dev/null
+++ b/tv/5pkgs/haskell/xmonad-tv/src/THEnv/JSON.hs
@@ -0,0 +1,18 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module THEnv.JSON where
+
+import Data.Aeson (eitherDecode,FromJSON)
+import Data.ByteString.Lazy.Char8 (pack)
+import Language.Haskell.TH.Syntax (Exp,Lift(lift),Q)
+import THEnv (getCompileEnv)
+import Control.Monad
+
+getCompileEnvJSON :: (FromJSON a) => String -> Q a
+getCompileEnvJSON name =
+    either error (id :: a -> a) . eitherDecode . pack <$>  getCompileEnv name
+
+getCompileEnvJSONExp ::
+  forall proxy a. (FromJSON a, Lift a) => proxy a -> String -> Q Exp
+getCompileEnvJSONExp _ =
+    (lift :: a -> Q Exp) <=< getCompileEnvJSON
diff --git a/tv/5pkgs/haskell/xmonad-tv/src/main.hs b/tv/5pkgs/haskell/xmonad-tv/src/main.hs
index c83b411b..b8ddd27e 100644
--- a/tv/5pkgs/haskell/xmonad-tv/src/main.hs
+++ b/tv/5pkgs/haskell/xmonad-tv/src/main.hs
@@ -1,4 +1,6 @@
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeApplications #-}
 
 module Main (main) where
 
@@ -32,10 +34,23 @@ import XMonad.Stockholm.Pager
 import XMonad.Stockholm.Shutdown
 import qualified Paths
 
+import THEnv.JSON (getCompileEnvJSONExp)
+
 
 myFont :: String
 myFont = "-schumacher-*-*-*-*-*-*-*-*-*-*-*-iso10646-*"
 
+myScreenWidth :: Dimension
+myScreenWidth =
+  $(getCompileEnvJSONExp (id @Dimension) "XMONAD_BUILD_SCREEN_WIDTH")
+
+myTermFontWidth :: Dimension
+myTermFontWidth =
+  $(getCompileEnvJSONExp (id @Dimension) "XMONAD_BUILD_TERM_FONT_WIDTH")
+
+myTermPadding :: Dimension
+myTermPadding = 2
+
 
 main :: IO ()
 main = getArgs >>= \case
@@ -46,7 +61,6 @@ main = getArgs >>= \case
 
 mainNoArgs :: IO ()
 mainNoArgs = do
-    let width = 1366
     workspaces0 <- getWorkspaces0
     handleShutdownEvent <- newShutdownEventHandler
     launch
@@ -60,8 +74,9 @@ mainNoArgs = do
                 smartBorders $
                   ResizableTall
                     1
-                    (10 * 6 / width)
-                    ((80 * 6 + 2 * (1+1+1))/width) []
+                    (fromIntegral (10 * myTermFontWidth) / fromIntegral myScreenWidth)
+                    (fromIntegral (80 * myTermFontWidth + 2 * (myTermPadding + borderWidth def)) / fromIntegral myScreenWidth)
+                    []
                   |||
                   Full
             , manageHook =
diff --git a/tv/5pkgs/haskell/xmonad-tv/src/xmonad-tv.cabal b/tv/5pkgs/haskell/xmonad-tv/src/xmonad-tv.cabal
index f10bc4ae..d07e2b15 100644
--- a/tv/5pkgs/haskell/xmonad-tv/src/xmonad-tv.cabal
+++ b/tv/5pkgs/haskell/xmonad-tv/src/xmonad-tv.cabal
@@ -9,10 +9,14 @@ cabal-version: >=1.10
 executable xmonad
   main-is: main.hs
   build-depends:
+    aeson,
     base,
+    bytestring,
     containers,
     directory,
     extra,
+    template-haskell,
+    th-env,
     unix,
     X11,
     xmonad,
@@ -20,6 +24,7 @@ executable xmonad
     xmonad-stockholm
   other-modules:
     Helpers.Path,
-    Paths
+    Paths,
+    THEnv.JSON
   default-language: Haskell2010
   ghc-options: -O2 -Wall -threaded