bild: port to haskell

1 files changed, 54 insertions, 0 deletions

diff --git a/Biz/Bild.hs b/Biz/Bild.hs
new file mode 100644
index 0000000..565792e
--- /dev/null
+++ b/Biz/Bild.hs
@@ -0,0 +1,54 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NoImplicitPrelude #-}
+
+-- | A general purpose build tool.
+--
+-- - with a nix build, results are linked in _bild/nix/<target>
+-- - for a dev build, results are stored in _bild/dev/<target>
+module Biz.Bild where
+
+import Alpha
+import qualified System.Directory as Dir
+import qualified System.Environment as Env
+import qualified System.Exit as Exit
+import System.FilePath ((</>))
+import qualified System.Process as Process
+
+main :: IO ()
+main = Env.getArgs /> head >>= \case
+  Nothing -> do
+    basename <- Env.getProgName
+    Exit.die <| "usage: " <> basename <> " <target>"
+  Just target -> nixBuild target
+
+{-
+TODO:
+- parse target syntax
+- write dev builder for ghc/ghcjs
+-}
+
+type Target = String
+
+nixBuild :: Target -> IO ()
+nixBuild target = do
+  root <- Env.getEnv "BIZ_ROOT"
+  cwd <- Dir.getCurrentDirectory
+  let qualifiedTarget = reps root "" cwd <> target
+  Process.callProcess
+    "nix-build"
+    [ "-o",
+      root </> "_bild/nix" </> qualifiedTarget,
+      root </> "default.nix",
+      "--attr",
+      qualifiedTarget
+    ]
+
+-- | Replace 'a' in 's' with 'b'.
+reps :: String -> String -> String -> String
+reps a b s@(x : xs) =
+  if isPrefixOf a s
+    then-- then, write 'b' and replace jumping 'a' substring
+      b ++ reps a b (drop (length a) s)
+    else-- then, write 'x' char and try to replace tail string
+      x : reps a b xs
+reps _ _ [] = []