Add Kotoba Plus Code encode/decode binding

.github/workflows/main.yml

@@ -1,14 +1,14 @@
 name: CI
 on: [push, pull_request, workflow_dispatch]
 jobs:
   # C implementation. Lives in c/, tested with bazel.
   test-c:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: c
     steps:
       - uses: actions/checkout@v4
       - uses: bazelbuild/setup-bazelisk@v3
       - name: test
         run: bazel test --test_output=all ${OLC_PATH}:all
       - name: check formatting
@@ -17,37 +17,37 @@
   # C implementation. Lives in c/, tested with bazel.
   # Use Mac with Apple Silicon for this test because of different floating point math
   # which can affect test results https://github.com/google/open-location-code/issues/652
   test-c-macos-latest:
     runs-on: macos-latest
     env:
       OLC_PATH: c
     steps:
       - uses: actions/checkout@v4
       - uses: bazelbuild/setup-bazelisk@v3
       - name: test
         run: bazel test --test_output=all ${OLC_PATH}:all
 
   # C++ implementation. Lives in cpp/, tested with bazel.
   test-cpp:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: cpp
     steps:
       - uses: actions/checkout@v4
       - uses: bazelbuild/setup-bazelisk@v3
       - name: test
         run: bazel test --test_output=all ${OLC_PATH}:all
       - name: check formatting
         run: cd ${OLC_PATH} && bash clang_check.sh
 
   # Dart implementation. Lives in dart/.
   test-dart:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: dart
     steps:
       - uses: actions/checkout@v4
       - uses: dart-lang/setup-dart@v1
       - name: test
         run: |
           cd ${OLC_PATH}
@@ -55,13 +55,13 @@
           bash checks.sh
 
   # Go implementation. Lives in go/. Tests fail if files have not been formatted with gofmt.
   test-go:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: go
     steps:
     - uses: actions/checkout@v4
     - uses: actions/setup-go@v5
       with:
         go-version: '1.23'
     - name: test
@@ -75,7 +75,7 @@
         go test ./ -v
 
   # Java implementation. Lives in java/, tested with bazel and maven.
   test-java:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: java
@@ -95,7 +95,7 @@
         run: bazel test --test_output=all ${OLC_PATH}:all && cd ${OLC_PATH} && mvn package -Dsurefire.useFile=false -DdisableXmlReport=true
 
   # Javascript Closure library implementation. Lives in js/closure, tested with bazel.
   test-js-closure:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: js/closure
@@ -108,7 +108,7 @@
           cd js && npm install && ./node_modules/.bin/eslint closure/*js
 
   # Javascript implementation. Lives in js/.
   test-js:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: js
@@ -120,7 +120,7 @@
           bash checks.sh
 
   # Python implementation. Lives in python/, tested with bazel.
   test-python:
     runs-on: ubuntu-latest
     env:
       OLC_PATH: python
@@ -161,6 +161,30 @@
           cd ${OLC_PATH} && ruby test/plus_codes_test.rb
           rubocop --config rubocop.yml
 
+  # Kotoba implementation. Lives in kotoba/. Compiles .kotoba to wasm with
+  # kotoba CLI v0.7.2 and runs vendored Plus Code fixtures.
+  test-kotoba:
+    runs-on: ubuntu-latest
+    env:
+      OLC_PATH: kotoba
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '22'
+      - name: Install kotoba CLI v0.7.2
+        run: |
+          curl -fsSL -o /tmp/kotoba-linux-amd64.tar.gz \
+            https://github.com/kotoba-lang/kotoba/releases/download/v0.7.2/kotoba-linux-amd64.tar.gz
+          echo "95e225461e1b8a21849b251e8c8b654693d2c8a516b258532771651e978e1977  /tmp/kotoba-linux-amd64.tar.gz" | sha256sum -c
+          mkdir -p /tmp/kotoba-cli
+          tar -xzf /tmp/kotoba-linux-amd64.tar.gz -C /tmp/kotoba-cli
+          sudo install -m 755 /tmp/kotoba-cli/kotoba /usr/local/bin/kotoba
+      - name: test
+        run: |
+          cd ${OLC_PATH}
+          bash checks.sh
+
   # Rust implementation. Lives in rust/.
   test-rust:
     runs-on: ubuntu-latest

kotoba/README.md

@@ -0,0 +1,51 @@
+# Kotoba library for Open Location Code
+
+This is a Plus Code (Open Location Code) encode/decode binding for
+[Kotoba](https://github.com/kotoba-lang/kotoba) CLI v0.7.2.
+
+Kotoba cannot FFI. The implementation is self-contained in
+`openlocationcode.kotoba` and compiles to host-independent wasm32 (`i64-v1`).
+
+## Integers only (microdegrees)
+
+The v0.7.2 wasm32 backend has no IEEE floats. Coordinates are **microdegrees**
+(`i64`): 1 unit = 1e-6 degree. A Plus Code is two little-endian i64 words of
+ASCII (word 0 = chars 0–7, word 1 = chars 8–15; unused bytes are 0).
+
+This matches the integer path in `go/encode.go` / `go/decode.go`, not the
+float `Encode`/`Decode` wrappers in other language directories.
+
+## Public API
+
+| Function | Arguments | Result |
+| --- | --- | --- |
+| `encode-word` | `lat-udeg`, `lng-udeg`, `code-len`, `word-ix` | packed ASCII word (`0` or `1`) |
+| `encode-char` | `lat-udeg`, `lng-udeg`, `code-len`, `pos` | ASCII code unit |
+| `decode-lat-lo` / `decode-lng-lo` | `w0`, `w1` | south-west corner, microdegrees |
+| `decode-lat-hi` / `decode-lng-hi` | `w0`, `w1` | north-east corner, microdegrees |
+| `decode-len` | `w0`, `w1` | significant digit count |
+| `main` | (none) | `0` if vendored fixtures pass |
+
+v1 covers full-code encode/decode only (no shorten/recover).
+
+## Testing
+
+From this directory, with kotoba CLI v0.7.2 and Node.js on `PATH`:
+
+```
+bash checks.sh
+```
+
+`checks.sh` compiles `openlocationcode.kotoba` to wasm, checks the module has
+wasm magic and no imports, instantiates it twice (wasm fuel is per-instance),
+requires `main() === 0` for encode fixtures, then calls the decode exports
+against the vendored vectors.
+
+Fixtures in `testdata/` are a subset of `../test_data/encoding.csv` and
+`../test_data/decoding.csv`, converted to microdegrees.
+
+## Compile
+
+```
+kotoba compile openlocationcode.kotoba --target wasm --output openlocationcode.wasm --json
+```

kotoba/checks.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+# Compile the Kotoba Open Location Code binding and run vendored fixtures.
+# Must run from within the kotoba directory.
+if [ "$(basename "$PWD")" != "kotoba" ]; then
+  echo "$0: must be run from within the kotoba directory!"
+  exit 1
+fi
+
+set -euo pipefail
+
+KOTOBA_BIN="${KOTOBA:-kotoba}"
+OUT="${TMPDIR:-/tmp}/openlocationcode.wasm"
+
+"$KOTOBA_BIN" compile openlocationcode.kotoba --target wasm --output "$OUT" --json
+node run_wasm.mjs "$OUT"