Add Haskell bindings for SCIP (#16)

Co-authored-by: Don Stewart <[email protected]>
Co-authored-by: Varun Gandhi <[email protected]>

Author: 3 people

.gitattributes

@@ -1,4 +1,5 @@
 bindings/typescript/scip.ts linguist-generated=true
 bindings/go/scip/scip.pb.go linguist-generated=true
 bindings/rust/src/scip.rs linguist-generated=true
+bindings/haskell/src/Proto/**.hs linguist-generated=true
 yarn.lock linguist-generated=true

.github/workflows/haskell.yml

@@ -0,0 +1,50 @@
+name: Haskell
+on:
+  pull_request:
+    paths:
+      - '.github/workflows/**'
+      - '**.hs'
+      - '**.cabal'
+
+jobs:
+  ci:
+    strategy:
+      fail-fast: false
+      matrix:
+        ghc: [8.10.7]
+    runs-on: ubuntu-latest
+    container:
+      # Ubuntu with ghcup already installed
+      image: ghcr.io/facebookincubator/hsthrift/ci-base:ghcup
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Install additional tools
+        run: |
+          apt-get update
+          apt install -y unzip
+      - name: Install GHC ${{ matrix.ghc }}
+        run: ghcup install ghc ${{ matrix.ghc }} --set
+      - name: Install cabal-install 3.6
+        run: ghcup install cabal 3.6.0.0 --set
+      - name: Add GHC and cabal to PATH
+        run: echo "$HOME/.ghcup/bin" >> "$GITHUB_PATH"
+      - name: Install protoc
+        run: |
+          PROTOC_ZIP=protoc-3.14.0-linux-x86_64.zip
+          curl -OL https://github.com/protocolbuffers/protobuf/releases/download/v3.14.0/"$PROTOC_ZIP"
+          unzip -o "$PROTOC_ZIP" -d /usr/local bin/protoc
+          unzip -o "$PROTOC_ZIP" -d /usr/local 'include/*'
+          rm -f $PROTOC_ZIP
+      - name: Populate hackage index
+        run: cabal update
+        working-directory: bindings/haskell
+      - name: Build proto-lens-protoc wrapper
+        run: cabal install proto-lens-protoc
+        working-directory: bindings/haskell
+      - name: Generate Haskell
+        run: protoc --plugin=protoc-gen-haskell="$HOME/.cabal/bin/proto-lens-protoc" --haskell_out=src --proto_path=../.. scip.proto
+        working-directory: bindings/haskell
+      - name: Build source
+        run: cabal build
+        working-directory: bindings/haskell

Development.md

@@ -4,7 +4,7 @@
 
 - [bindings/](./bindings/): Contains a mix of generated and hand-written
   bindings for different languages.
-  - The TypeScript and Rust bindings are auto-generated.
+  - The TypeScript, Rust and Haskell bindings are auto-generated.
   - The Go bindings include protoc-generated code as well as extra
     functionality, such as for converting a SCIP index into an LSIF index.
     This is used by the CLI below as well as the
@@ -24,6 +24,7 @@
    ```
    ./dev/proto-generate.sh
    ```
+   For the Haskell bindings, see `bindings/haskell/README.md`.
 2. Regenerating snapshots after making changes to the CLI.
    ```
    go test ./cmd -update-snapshots

bindings/haskell/.gitignore

@@ -0,0 +1 @@
+dist-newstyle/

bindings/haskell/LICENSE

@@ -0,0 +1 @@
+../../LICENSE

bindings/haskell/README.md

@@ -0,0 +1,50 @@
+[![CI](https://github.com/sourcegraph/scip/actions/workflows/haskell.yml/badge.svg)](https://github.com/sourcegraph/scip/actions/workflows/haskell.yml/badge.svg)
+
+# Haskell bindings for SCIP
+
+These bindings use [Google's proto-lens generator for Haskell](https://github.com/google/proto-lens).
+
+Building: see the following workflow file for most up to date:
+https://github.com/sourcegraph/scip/blob/main/.github/workflows/haskell.yml
+
+First, get a working GHC environment:
+
+```sh
+# Linux
+GHCUPVERSION=0.1.17.4
+curl --proto '=https' --tlsv1.2 -sSf https://downloads.haskell.org/~ghcup/$GHCUPVERSION/x86_64-linux-ghcup-$GHCUPVERSION > /usr/bin/ghcup && \
+chmod +x /usr/bin/ghcup
+ghcup install ghc 8.10.7 --set
+ghcup install cabal 3.6.0.0 --set
+```
+
+```sh
+# macOS
+GHCUPVERSION=0.1.17.4
+curl --proto '=https' --tlsv1.2 -sSf https://downloads.haskell.org/~ghcup/$GHCUPVERSION/x86_64-apple-darwin-ghcup-$GHCUPVERSION > /usr/local/bin/ghcup && \
+chmod +x /usr/local/bin/ghcup
+ghcup install ghc 8.10.7 --set
+ghcup install cabal 3.6.0.0 --set
+```
+
+Next, install Google's `protoc` compiler. See: https://github.com/google/proto-lens/blob/master/docs/installing-protoc.md
+
+Then install the haskell generator from the proto-lens packages:
+
+```
+cabal install proto-lens-protoc
+```
+
+Finally, generate the source files manually in `src/*`
+
+```sh
+# working directory: bindings/haskell
+protoc --plugin=protoc-gen-haskell=`which proto-lens-protoc` --haskell_out=src --proto_path=../.. scip.proto
+```
+
+Build the library as normal:
+
+```
+# working directory: bindings/haskell
+cabal build
+```

bindings/haskell/scip.cabal

@@ -0,0 +1,23 @@
+cabal-version:      3.6
+
+name:               scip
+version:            0.1.0.0
+synopsis:           Haskell bindings for SCIP Code Intelligence Protocol
+license:            Apache-2.0
+license-file:       LICENSE
+author:             SCIP Maintainers
+maintainer:         [email protected]
+homepage:           https://github.com/sourcegraph/scip
+category:           Language
+build-type:         Simple
+
+library
+    ghc-options: -Wall
+    exposed-modules:
+        Proto.Scip,
+        Proto.Scip_Fields
+    hs-source-dirs:   src
+    default-language: Haskell2010
+    build-depends:
+        proto-lens-runtime ^>= 0.7.0.0,
+        base ^>= 4.14.0.0