feat(third_party/bazel): Check in rules_haskell from Tweag

third_party/bazel/rules_haskell/tests/haskell_doctest/BUILD.bazel

@@ -0,0 +1,73 @@
+load(
+    "@io_tweag_rules_haskell//haskell:haskell.bzl",
+    "haskell_doctest",
+    "haskell_library",
+    "haskell_test",
+)
+
+package(default_testonly = 1)
+
+haskell_library(
+    name = "lib-a",
+    srcs = ["Foo.hs"],
+    tags = ["requires_zlib"],
+    deps = [
+        "//tests/data:ourclibrary",
+        "//tests/hackage:base",
+        "@zlib.dev//:zlib",
+    ],
+)
+
+haskell_library(
+    name = "lib-b",
+    srcs = [
+        "Bar.hs",
+        "Baz.hs",
+        "Quux.hsc",
+    ],
+    tags = ["requires_zlib"],
+    deps = [
+        ":lib-a",
+        "//tests/hackage:base",
+    ],
+)
+
+haskell_doctest(
+    name = "doctest-lib-all-fail",
+    tags = ["manual"],  # must FAIL
+    visibility = ["//visibility:public"],
+    deps = [":lib-b"],
+)
+
+haskell_doctest(
+    name = "doctest-lib-all-success",
+    doctest_flags = ["-DMAGIC_DOCTEST_THING"],
+    tags = ["requires_doctest"],
+    visibility = ["//visibility:public"],
+    deps = [":lib-b"],
+)
+
+haskell_doctest(
+    name = "doctest-lib",
+    modules = ["Bar"],  # exclude Baz and succeed
+    tags = ["requires_doctest"],
+    visibility = ["//visibility:public"],
+    deps = [":lib-b"],
+)
+
+haskell_test(
+    name = "bin",
+    srcs = ["Main.hs"],
+    tags = ["requires_zlib"],
+    deps = [
+        ":lib-a",
+        "//tests/hackage:base",
+    ],
+)
+
+haskell_doctest(
+    name = "doctest-bin",
+    tags = ["requires_doctest"],
+    visibility = ["//visibility:public"],
+    deps = [":bin"],
+)

third_party/bazel/rules_haskell/tests/haskell_doctest/Bar.hs

@@ -0,0 +1,13 @@
+module Bar (bar) where
+
+import Foo (foo)
+import Numeric
+
+-- |
+-- >>> bar
+-- 9
+-- >>> showInt bar "" ++ "!"
+-- "9!"
+
+bar :: Int
+bar = 4 + foo

third_party/bazel/rules_haskell/tests/haskell_doctest/Baz.hs

@@ -0,0 +1,14 @@
+{-# LANGUAGE CPP #-}
+
+module Baz (baz) where
+
+-- |
+-- >>> baz
+-- 101
+
+baz :: Int
+#ifndef MAGIC_DOCTEST_THING
+baz = 100
+#else
+baz = 101
+#endif

third_party/bazel/rules_haskell/tests/haskell_doctest/Foo.hs

@@ -0,0 +1,14 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+module Foo (foo) where
+
+import Foreign.C.Types (CInt(..))
+
+foreign import ccall "c_add_one"
+  c_add_one :: CInt -> CInt
+
+-- |
+-- >>> foo
+-- 5
+foo :: Int
+foo = fromIntegral (c_add_one 4)

third_party/bazel/rules_haskell/tests/haskell_doctest/Main.hs

@@ -0,0 +1,6 @@
+module Main (main) where
+
+import Foo (foo)
+
+main :: IO ()
+main = print foo

third_party/bazel/rules_haskell/tests/haskell_doctest/Quux.hsc

@@ -0,0 +1,11 @@
+-- | This module is in a .hsc file, this way we test that improt directories
+-- are passed correctly to the doctest executable.
+
+module Quux (quux) where
+
+-- |
+-- >>> quux
+-- 68
+
+quux :: Int
+quux = 68