bild: support incremental compilation

Closes https://github.com/bsima/biz/issues/9

1 files changed, 128 insertions, 23 deletions

diff --git a/Biz/Bild.hs b/Biz/Bild.hs
index 565792e..7e67b8d 100644
--- a/Biz/Bild.hs
+++ b/Biz/Bild.hs
@@ -1,4 +1,6 @@
 {-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards #-}
 {-# LANGUAGE NoImplicitPrelude #-}
 
 -- | A general purpose build tool.
@@ -7,41 +9,144 @@
 -- - for a dev build, results are stored in _bild/dev/<target>
 module Biz.Bild where
 
-import Alpha
+import Alpha hiding ((<.>), sym)
+import qualified Data.Char as Char
+import qualified Data.List as List
+import qualified Data.Text as Text
 import qualified System.Directory as Dir
 import qualified System.Environment as Env
 import qualified System.Exit as Exit
-import System.FilePath ((</>))
+import System.FilePath ((<.>), (</>))
 import qualified System.Process as Process
+import Text.Regex.Applicative
+import qualified Prelude
 
 main :: IO ()
 main = Env.getArgs /> head >>= \case
-  Nothing -> do
-    basename <- Env.getProgName
-    Exit.die <| "usage: " <> basename <> " <target>"
-  Just target -> nixBuild target
+  Nothing -> Exit.die "usage: bild <target>"
+  Just target -> analyze target >>= build
 
-{-
-TODO:
-- parse target syntax
-- write dev builder for ghc/ghcjs
--}
+type Namespace = String
 
-type Target = String
+type Dep = String
 
-nixBuild :: Target -> IO ()
-nixBuild target = do
+type Exe = String
+
+data Compiler = Ghc | Ghcjs | Nix
+  deriving (Show)
+
+data Target
+  = Target
+      { -- | Output executable name
+        exe :: Exe,
+        -- | Fully qualified namespace partitioned by '.'
+        namespace :: Namespace,
+        -- | Absolute path to file
+        path :: FilePath,
+        -- | Parsed/detected dependencies
+        deps :: [Dep],
+        -- | Which compiler should we use?
+        compiler :: Compiler
+      }
+  deriving (Show)
+
+analyze :: String -> IO Target
+analyze s = 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
-    ]
+  -- this is a hack to support multiple file types. Ideally we would just detect
+  -- which file extensions exist
+  let path = cwd </> reps "." "/" s |> reps "/hs" ".hs" |> reps "/nix" ".nix"
+  content <- lines </ Prelude.readFile path
+  let exe = content /> match metaExe |> catMaybes |> head |> require "exe"
+  return
+    Target
+      { namespace =
+          require "namespace"
+            <| path
+            |> reps root ""
+            |> reps ".hs" ""
+            |> reps ".nix" ""
+            |> reps "/" "."
+            |> List.stripPrefix "."
+            >>= match metaNamespace,
+        deps = content /> match metaDep |> catMaybes,
+        compiler =
+          if ".hs" `List.isSuffixOf` path
+            then if ".js" `List.isSuffixOf` exe then Ghcjs else Ghc
+            else Nix,
+        ..
+      }
+
+build :: Target -> IO ()
+build Target {..} = do
+  root <- Env.getEnv "BIZ_ROOT"
+  case compiler of
+    Ghc -> do
+      putText <| "bild: ghc: " <> Text.pack namespace
+      let out = root </> "_bild/dev/bin"
+      Dir.createDirectoryIfMissing True out
+      Process.callProcess
+        "ghc"
+        [ "-Werror",
+          "-i" <> root,
+          "-odir",
+          root </> "_bild/int",
+          "-hidir",
+          root </> "_bild/int",
+          "--make",
+          path,
+          "-main-is",
+          namespace,
+          "-o",
+          out </> exe
+        ]
+    Ghcjs -> do
+      putText <| "bild: ghcjs: " <> Text.pack namespace
+      let out = root </> "_bild/dev/static"
+      Dir.createDirectoryIfMissing True out
+      Process.callProcess
+        "ghcjs"
+        [ "-Werror",
+          "-i" <> root,
+          "-odir",
+          root </> "_bild/int",
+          "-hidir",
+          root </> "_bild/int",
+          "--make",
+          path,
+          "-main-is",
+          namespace,
+          "-o",
+          out </> exe
+        ]
+    Nix -> do
+      putText <| "bild: nix: " <> Text.pack namespace
+      cwd <- Dir.getCurrentDirectory
+      let qualifiedTarget = reps root "" cwd <> namespace
+      Process.callProcess
+        "nix-build"
+        [ "-o",
+          root </> "_bild/nix" </> qualifiedTarget,
+          root </> "default.nix",
+          "--attr",
+          qualifiedTarget
+        ]
+
+metaNamespace :: RE Char Namespace
+metaNamespace = name <> many (sym '.') <> name
+  where
+    name = many (psym Char.isUpper) <> many (psym Char.isLower)
+
+metaDep :: RE Char Dep
+metaDep = string "-- : dep " *> many (psym Char.isAlpha)
+
+metaExe :: RE Char Exe
+metaExe = string "-- : exe " *> many (psym (/= ' '))
+
+require :: Text -> Maybe a -> a
+require s (Just x) = x
+require s Nothing = panic <| s <> " not found"
 
 -- | Replace 'a' in 's' with 'b'.
 reps :: String -> String -> String -> String