setup bazel to run emscripten on files

it works!

.bazelversion

@@ -0,0 +1 @@
+6.3.2

.gitignore

@@ -13,3 +13,9 @@
 *.cmake
 Makefile
 CMakeCache.txt
+
+# bazel
+bazel-bin
+bazel-conway-rts
+bazel-out
+bazel-testlogs

BUILD

@@ -0,0 +1,10 @@
+load("@rules_cc//cc:defs.bzl", "cc_library")
+
+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+  name = "vector2",
+  srcs = ["src/Vector2.cpp"],
+  hdrs = ["include/Vector2.hpp", "include/ISerializable.hpp"],
+  copts = ["-I include"],
+)

WORKSPACE

@@ -0,0 +1,38 @@
+workspace(
+  name = "conway_rts",
+)
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+http_archive(
+  name = "aspect_rules_js",
+  sha256 = "77c4ea46c27f96e4aadcc580cd608369208422cf774988594ae8a01df6642c82",
+  strip_prefix = "rules_js-1.32.2",
+  url = "https://github.com/aspect-build/rules_js/releases/download/v1.32.2/rules_js-v1.32.2.tar.gz",
+)
+
+load("@aspect_rules_js//js:repositories.bzl", "rules_js_dependencies")
+rules_js_dependencies()
+
+load("@rules_nodejs//nodejs:repositories.bzl", "DEFAULT_NODE_VERSION", "nodejs_register_toolchains")
+nodejs_register_toolchains(
+  name = "nodejs",
+  node_version = DEFAULT_NODE_VERSION,
+)
+
+# Emscripten toolchain
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+http_archive(
+    name = "emsdk",
+    sha256 = "5dd94e557b720800a60387ec078bf3b3a527cbd916ad74a696fe399f1544474f",
+    strip_prefix = "emsdk-3.1.46/bazel",
+    url = "https://github.com/emscripten-core/emsdk/archive/refs/tags/3.1.46.tar.gz",
+)
+
+load("@emsdk//:deps.bzl", emsdk_deps = "deps")
+emsdk_deps()
+
+load("@emsdk//:emscripten_deps.bzl", emsdk_emscripten_deps = "emscripten_deps")
+emsdk_emscripten_deps(emscripten_version = "3.1.46")
+
+load("@emsdk//:toolchains.bzl", "register_emscripten_toolchains")
+register_emscripten_toolchains()

client/BUILD

@@ -0,0 +1,40 @@
+load("@emsdk//emscripten_toolchain:wasm_rules.bzl", "wasm_cc_binary")
+
+package(default_visibility = ["//visibility:public"])
+
+DEFAULT_EMSCRIPTEN_LINKOPTS = [
+  # LTO broken when using hermetic emsdk
+  # "-flto",                          # Specify lto (has to be set on for compiler as well)
+  "--bind",                           # Compiles the source code using the Embind bindings to connect C/C++ and JavaScript
+  "--closure 1",                      # Run the closure compiler
+  "-s MALLOC=emmalloc",               # Switch to using the much smaller implementation
+  "-s ALLOW_MEMORY_GROWTH=0",         # Our example doesn't need memory growth
+  "-s USE_PTHREADS=0",                # Disable pthreads
+  "-s ASSERTIONS=0",                  # Turn off assertions
+  # "-s EXPORT_ES6=1",                  # Export as es6 module, used for rollup
+  "-s MODULARIZE=1",                  # Allows us to manually invoke the initializatio of wasm
+  "-s EXPORT_NAME=createModule",      # Not used, but good to specify
+  # "-s USE_ES6_IMPORT_META=1",         # needed for somethingggg --- Disable loading from import meta since we use rollup
+  "-s SINGLE_FILE=1",                 # Pack all webassembly into base64
+  "-s DISABLE_EXCEPTION_CATCHING=1",  # Disable all exception catching
+  "-s NODEJS_CATCH_EXIT=0",           # We don't have a 'main' so disable exit() catching
+]
+
+WASM_LINKOPTS = [
+  "-s WASM=0",          # Specify wasm output
+]
+
+cc_binary(
+  name = "lib-wasm.js",
+  srcs = ["bindings.cpp"],
+  linkopts = DEFAULT_EMSCRIPTEN_LINKOPTS + WASM_LINKOPTS,
+  deps = [
+    "//:vector2",
+    # "//hello-world/cpp:localtime",
+  ],
+)
+
+wasm_cc_binary(
+  name = "lib-wasm",
+  cc_target = ":lib-wasm.js",
+)

client/bindings.cpp

@@ -0,0 +1,12 @@
+#include "emscripten/bind.h"
+#include "include/Vector2.hpp"
+
+EMSCRIPTEN_BINDINGS(Vector2) {
+  emscripten::class_<Vector2>("Vector2")
+    .constructor<int, int>()
+    .function("x", &Vector2::GetX)
+    .function("y", &Vector2::GetY)
+    .function("SetX", &Vector2::SetX)
+    .function("SetY", &Vector2::SetY)
+    ;
+}

include/ISerializable.hpp

@@ -6,6 +6,9 @@
 template<typename T>
 class ISerializable {
   public:
+    // https://stackoverflow.com/a/8513537
+    virtual ~ISerializable() {} // all destructors must exist (necessary for bazel)
+
     // https://stackoverflow.com/a/437507/21507383
     // friendship is not transitive or inherited, so these have to
     // be redeclared if private access is needed
@@ -21,7 +24,4 @@ class ISerializable {
     virtual bool ParseFromIstream(std::istream& in) = 0;
 };
 
-// https://stackoverflow.com/a/8513537
-// ISerializable<>::~ISerializable() { } // all destructors must exist
-
 #endif // CONWAY_INCLUDE_ISERIALIZABLE_HPP

include/Vector2.hpp

@@ -46,6 +46,12 @@ class Vector2: public ISerializable<Vector2> {
       if constexpr (Index == 0) return x;
       if constexpr (Index == 1) return y;
     }
+
+    // embind stuff
+    int GetX() const { return _x; }
+    int GetY() const { return _y; }
+    void SetX(int x) { _x = x; }
+    void SetY(int y) { _y = y; }
 };
 
 // https://www.albertogramaglia.com/modern-cpp-structured-binding/