Move purescript-ast to a bazel rule

We want to work around an issue with packages not at the top-level.

This follows the change we made for `purescript-cst` in
8f77f15f5d388b6a17c6a216ea1644caeda609af. I.e. addressing the problem of
Haskell packages in a sub-directory not really working with `stack ls
dependencies json` at the moment:
tweag/rules_haskell#1392 (comment).

WORKSPACE.bazel

@@ -72,6 +72,22 @@ http_archive(
     ],
 )
 
+http_archive(
+    name = "purescript_ast",
+    build_file = "//third_party/purescript-ast:purescript-ast.BUILD",
+    patch_args = [
+        "-p1",
+    ],
+    patches = [
+        "//third_party/purescript-ast:purescript-ast-cabal-file.patch",
+    ],
+    strip_prefix = "purescript-81909a9585b00bc99cc47c7959fbc5ae2e1ff285/lib/purescript-ast",
+    sha256 = "f2d685b754d93328fd2d175af0748f6f3bce7335c5d14157427876df38b566c3",
+    urls = [
+        "https://github.com/joneshf/purescript/archive/81909a9585b00bc99cc47c7959fbc5ae2e1ff285.zip",
+    ],
+)
+
 http_archive(
     name = "purescript_cst",
     build_file = "//third_party/purescript-cst:purescript-cst.BUILD",
@@ -159,6 +175,23 @@ stack_snapshot(
         "optparse-applicative",
         "pathwalk",
         "rio",
+        # `purescript-ast` dependencies
+        # These have to be here so the `//third_party/purescript:purescript-ast` package can pick them up.
+        # If we ever can get rid of the `//third_party/purescript:purescript-ast` package,
+        # we can remove these dependencies
+        "aeson",
+        "base",
+        "base-compat",
+        "bytestring",
+        "containers",
+        "deepseq",
+        "filepath",
+        "microlens-platform",
+        "mtl",
+        "protolude",
+        "scientific",
+        "text",
+        "vector",
         # `purescript-cst` dependencies
         # These have to be here so the `//third_party/purescript:purescript-cst` package can pick them up.
         # If we ever can get rid of the `//third_party/purescript:purescript-cst` package,
@@ -167,7 +200,6 @@ stack_snapshot(
         "base",
         "containers",
         "dlist",
-        "purescript-ast",
         "scientific",
         "semigroups",
         "text",
@@ -177,6 +209,7 @@ stack_snapshot(
         "@happy",
     ],
     vendored_packages = {
+        "purescript-ast": "@purescript_ast//:purescript-ast",
         "purescript-cst": "@purescript_cst//:purescript-cst",
     },
 )

snapshot.yaml

@@ -5,8 +5,4 @@ packages:
   - teardown-0.5.0.1@sha256:b7a6812637f79d81632bb7adebc5ad9a96fffacf3e5f655d5bf21728bd3786f9,2868
   - typed-process-0.2.6.0@sha256:c901c13d491441830eb23132ad6968243a56b98161629d260a26c0b13c735fcd,2136
   - unliftio-0.2.12@sha256:b089fbc2ff2628a963c2c4b12143f2020874e3e5144ffd6c62b25639a0ca1483,3325
-  - git: https://github.com/joneshf/purescript.git
-    commit: 81909a9585b00bc99cc47c7959fbc5ae2e1ff285
-    subdirs:
-      - lib/purescript-ast
 resolver: lts-13.26

third_party/purescript-ast/purescript-ast-cabal-file.patch

@@ -0,0 +1,80 @@
+diff --git a/purescript-ast.cabal b/purescript-ast.cabal
+new file mode 100644
+index 00000000..d886259e
+--- /dev/null
++++ b/purescript-ast.cabal
+@@ -0,0 +1,74 @@
++cabal-version: 1.12
++
++-- This file has been generated from package.yaml by hpack version 0.31.1.
++--
++-- see: https://github.com/sol/hpack
++--
++-- hash: 5e936f86b1ee77d33f4a9da5d917f41ca19c69b390366da8bdff54725ad5dc18
++
++name:           purescript-ast
++version:        0.13.6
++synopsis:       PureScript Programming Language Abstract Syntax Tree
++description:    Defines the underlying syntax of the PureScript Programming Language.
++category:       Language
++stability:      experimental
++homepage:       http://www.purescript.org/
++bug-reports:    https://github.com/purescript/purescript/issues
++author:         Phil Freeman <paf31@cantab.net>
++maintainer:     Gary Burgess <gary.burgess@gmail.com>, Hardy Jones <jones3.hardy@gmail.com>, Harry Garrood <harry@garrood.me>, Christoph Hegemann <christoph.hegemann1337@gmail.com>, Liam Goodacre <goodacre.liam@gmail.com>, Nathan Faubion <nathan@n-son.com>
++
++copyright:      (c) 2013-17 Phil Freeman, (c) 2014-19 Gary Burgess, (c) other contributors (see CONTRIBUTORS.md)
++license:        BSD3
++license-file:   LICENSE
++build-type:     Simple
++extra-source-files:
++    README.md
++
++source-repository head
++  type: git
++  location: https://github.com/purescript/purescript
++
++library
++  exposed-modules:
++      Control.Monad.Supply
++      Control.Monad.Supply.Class
++      Language.PureScript.AST
++      Language.PureScript.AST.Binders
++      Language.PureScript.AST.Declarations
++      Language.PureScript.AST.Exported
++      Language.PureScript.AST.Literals
++      Language.PureScript.AST.Operators
++      Language.PureScript.AST.SourcePos
++      Language.PureScript.AST.Traversals
++      Language.PureScript.Comments
++      Language.PureScript.Constants.Prim
++      Language.PureScript.Crash
++      Language.PureScript.Environment
++      Language.PureScript.Kinds
++      Language.PureScript.Label
++      Language.PureScript.Names
++      Language.PureScript.PSString
++      Language.PureScript.Traversals
++      Language.PureScript.TypeClassDictionaries
++      Language.PureScript.Types
++  other-modules:
++      Paths_purescript_ast
++  hs-source-dirs:
++      src
++  default-extensions: ConstraintKinds DataKinds DeriveFunctor DeriveFoldable DeriveTraversable DeriveGeneric DerivingStrategies EmptyDataDecls FlexibleContexts KindSignatures LambdaCase MultiParamTypeClasses NoImplicitPrelude PatternGuards PatternSynonyms RankNTypes RecordWildCards OverloadedStrings ScopedTypeVariables TupleSections ViewPatterns
++  ghc-options: -Wall -O2
++  build-depends:
++      aeson >=1.0 && <1.5
++    , base >=4.11 && <4.13
++    , base-compat >=0.6.0
++    , bytestring
++    , containers
++    , deepseq
++    , filepath
++    , microlens-platform >=0.3.9.0 && <0.4
++    , mtl >=2.1.0 && <2.3.0
++    , protolude >=0.1.6 && <0.2.4
++    , scientific >=0.3.4.9 && <0.4
++    , text
++    , vector
++  default-language: Haskell2010

third_party/purescript-ast/purescript-ast.BUILD

@@ -0,0 +1,21 @@
+load(
+    "@rules_haskell//haskell:cabal.bzl",
+    "haskell_cabal_library",
+)
+
+load(
+    "@stackage//:packages.bzl",
+    "packages",
+)
+
+haskell_cabal_library(
+    name = "purescript-ast",
+    deps = packages["purescript-ast"].deps,
+    srcs = glob([
+        "**",
+    ]),
+    version = packages["purescript-ast"].version,
+    visibility = [
+        "//visibility:public",
+    ],
+)