Working nixified python build

This represents quite a few evenings of hacking. It doesn't build all of my
Python code, because my Python code is not up to snuff, but it builds the
examples and pulls in third party dependencies.

Some design points:

- I'm using buildPythonApplication in Builder.nix because it was getting way too
  annoying to wrap the Python script and set PYTHONPATH myself. Easier and more
  robust to just use the upstream nix builder
- Because of this, I had to generate a setup.py. Maybe switch to pyproject.toml
  in the future, whatever.
- Also because of this, Target.wrapper is becoming redundant. I'll just remove
  it when I get Guile built in nix.
- Biz/Bild.nix is getting messy and could use a refactor.
- In Builder.nix, I worked around the empty directories bug by just finding and
  deleting empty directories after unpacking. If its stupid but works it ain't
  stupid!
- I had to touch __init__.py files in all directories before building. Annoying!
- `repl` just works, which is awesome
- To ensure good Python code, I moved lints and added type checking to the
  build. So I can't build anything unless it passes those checks. This seems
  restrictive, but if I want to run some non-passing code, I can still use
  `repl`, so it's actually not inhibitory.

1 files changed, 82 insertions, 21 deletions

diff --git a/Biz/Bild.hs b/Biz/Bild.hs
index 7bfa788..19c8827 100644
--- a/Biz/Bild.hs
+++ b/Biz/Bild.hs
@@ -120,6 +120,7 @@ import qualified Biz.Cli as Cli
 import qualified Biz.Log as Log
 import Biz.Namespace (Namespace (..))
 import qualified Biz.Namespace as Namespace
+import Biz.Test ((@=?))
 import qualified Biz.Test as Test
 import qualified Conduit
 import qualified Control.Concurrent.Async as Async
@@ -152,21 +153,41 @@ main = Cli.main <| Cli.Plan help move test_ pure
     test_ =
       Test.group
         "Biz.Bild"
-        [ Test.unit "can bild bild" <| do
-            root <- Env.getEnv "BIZ_ROOT"
-            path <- Dir.makeAbsolute "Biz/Bild.hs"
-            case Namespace.fromPath root path of
-              Nothing -> Test.assertFailure "can't find ns for bild"
-              Just ns ->
-                analyze mempty ns
-                  +> build False False
-                  +> \case
-                    [Exit.ExitFailure _] ->
-                      Test.assertFailure "can't bild bild"
-                    _ ->
-                      pure ()
+        [ test_bildBild,
+          test_bildExamples
         ]
 
+test_bildBild :: Test.Tree
+test_bildBild =
+  Test.unit "can bild bild" <| do
+    root <- Env.getEnv "BIZ_ROOT"
+    path <- Dir.makeAbsolute "Biz/Bild.hs"
+    case Namespace.fromPath root path of
+      Nothing -> Test.assertFailure "can't find ns for bild"
+      Just ns ->
+        analyze mempty ns
+          +> build False False
+          +> \case
+            [Exit.ExitFailure _] ->
+              Test.assertFailure "can't bild bild"
+            _ ->
+              pure ()
+
+test_bildExamples :: Test.Tree
+test_bildExamples =
+  Test.unit "can bild examples" <| do
+    Env.getEnv "BIZ_ROOT" +> \root ->
+      ["c", "hs", "lisp", "rs"]
+        |> map ("Biz/Bild/Example." <>)
+        |> traverse Dir.makeAbsolute
+        /> map (Namespace.fromPath root)
+        /> catMaybes
+        +> foldM analyze mempty
+        +> build False False
+        +> \case
+          [] -> Test.assertFailure "asdf"
+          xs -> all (== Exit.ExitSuccess) xs @=? True
+
 move :: Cli.Arguments -> IO ()
 move args = do
   root <- Env.getEnv "BIZ_ROOT"
@@ -223,6 +244,7 @@ exitSummary exits =
 
 data Compiler
   = Copy
+  | CPython
   | Gcc
   | Ghc
   | Guile
@@ -234,6 +256,7 @@ data Compiler
 compilerExe :: IsString a => Compiler -> a
 compilerExe = \case
   Copy -> "cp"
+  CPython -> "python"
   Gcc -> "gcc"
   Ghc -> "ghc"
   Guile -> "guild"
@@ -321,7 +344,7 @@ isBuildableNs = \case
   (Namespace _ Namespace.Lisp) -> True
   (Namespace _ Namespace.Md) -> False
   (Namespace _ Namespace.None) -> False
-  (Namespace _ Namespace.Py) -> False
+  (Namespace _ Namespace.Py) -> True
   (Namespace _ Namespace.Sh) -> False
   (Namespace _ Namespace.Scm) -> True
   (Namespace _ Namespace.Rs) -> True
@@ -412,7 +435,33 @@ analyze hmap ns = case Map.lookup ns hmap of
         Namespace.Keys -> pure Nothing
         Namespace.Md -> pure Nothing
         Namespace.None -> pure Nothing
-        Namespace.Py -> pure Nothing
+        Namespace.Py ->
+          Meta.detectAll "#" contentLines |> \Meta.Parsed {..} ->
+            Target
+              { builder = Local user host,
+                wrapper = Nothing,
+                compiler = CPython,
+                compilerFlags =
+                  -- This doesn't really make sense for python, but I'll leave
+                  -- it here for eventual --dev builds
+                  [ "-c",
+                    "\"import py_compile;import os;"
+                      <> "py_compile.compile(file='"
+                      <> str path
+                      <> "', cfile=os.getenv('BIZ_ROOT')+'/_/int/"
+                      <> str path
+                      <> "', doraise=True)\""
+                  ],
+                sysdeps = psys,
+                langdeps = pdep,
+                outPath = outToPath pout,
+                out = pout,
+                srcs = Set.singleton path,
+                packageSet = "pythonWith",
+                ..
+              }
+              |> Just
+              |> pure
         Namespace.Sh -> pure Nothing
         Namespace.C ->
           Meta.detectAll "//" contentLines |> \Meta.Parsed {..} -> do
@@ -557,6 +606,8 @@ analyze hmap ns = case Map.lookup ns hmap of
                 outPath = outToPath pout,
                 out = pout,
                 srcs = Set.singleton absPath,
+                -- TODO: wrapper should just be removed, instead rely on
+                -- upstream nixpkgs builders to make wrappers
                 wrapper =
                   (pout == Meta.None)
                     ?: ( Nothing,
@@ -685,6 +736,9 @@ build andTest loud analysis =
   Env.getEnv "BIZ_ROOT" +> \root ->
     forM (Map.elems analysis) <| \target@Target {..} ->
       fst </ case compiler of
+        CPython ->
+          Log.info ["bild", "nix", "python", nschunk namespace]
+            >> nixBuild loud target
         Gcc ->
           Log.info ["bild", label, "gcc", nschunk namespace]
             >> proc loud namespace (toNixFlag compiler) compilerFlags
@@ -812,7 +866,7 @@ isModuleChar :: Char -> Bool
 isModuleChar c =
   elem c <| concat [['A' .. 'Z'], ['a' .. 'z'], ['.', '_'], ['0' .. '9']]
 
--- Matches on `(require :package)` forms and returns `package`. The `require`
+-- | Matches on `(require :package)` forms and returns `package`. The `require`
 -- function is technically deprecated in Common Lisp, but no new spec has been
 -- published with a replacement, and I don't wanna use asdf, so this is what we
 -- use for Lisp imports.
@@ -852,14 +906,15 @@ nixBuild loud Target {..} =
           -- is tightly coupled with the code in the nix builder and there's no
           -- way around that, methinks.
           args =
-            [ argstr "srcs" <| unwords <| map str <| (root </> path) : Set.toList srcs,
+            [ argstr "srcs" <| unwords <| map str <| Set.toList srcs <> [root </> path],
+              argstr "main" <| str <| Namespace.toModule namespace,
               argstr "root" <| str root,
               argstr "packageSet" packageSet,
-              (argstr "langDeps" <| unwords <| map str <| Set.toList langdeps) <|> mempty,
+              (langdeps == mempty) ?: (mempty, argstr "langdeps" <| unwords <| map str <| Set.toList langdeps),
+              (sysdeps == mempty) ?: (mempty, argstr "sysdeps" <| unwords <| map str <| Set.toList sysdeps),
               argstr "name" <| str <| outname out,
-              argstr "buildPhase" <| unwords
-                <| (Text.pack <| toNixFlag compiler) :
-              compilerFlags,
+              argstr "compileLine" <| unwords <| (Text.pack <| toNixFlag compiler) : compilerFlags,
+              ["--attr", selectBuilder namespace],
               [str <| root </> "Biz/Bild/Builder.nix"]
             ]
               |> mconcat
@@ -891,3 +946,9 @@ nixBuild loud Target {..} =
           onFailure = Log.fail ["bild", "symlink", nschunk namespace] >> Log.br,
           onSuccess = pure ()
         }
+
+selectBuilder :: Namespace -> Text
+selectBuilder = \case
+  Namespace _ Namespace.Hs -> "base"
+  Namespace _ Namespace.Py -> "python"
+  _ -> panic "no builder for this namespace"