Expose Luau bytecode loading API, add example

build.zig

@@ -58,10 +58,14 @@ pub fn build(b: *Build) void {
     test_step.dependOn(&run_tests.step);
 
     // Examples
-    const examples = [_]struct { []const u8, []const u8 }{
+    var common_examples = [_]struct { []const u8, []const u8 }{
         .{ "interpreter", "examples/interpreter.zig" },
         .{ "zig-function", "examples/zig-fn.zig" },
     };
+    const luau_examples = [_]struct { []const u8, []const u8 }{
+        .{ "luau-bytecode", "examples/luau-bytecode.zig" },
+    };
+    const examples = if (lua_version == .luau) &common_examples ++ luau_examples else &common_examples;
 
     for (examples) |example| {
         const exe = b.addExecutable(.{

examples/luau-bytecode.zig

@@ -0,0 +1,35 @@
+//! Run Luau bytecode
+
+// How to recompile `test.luau.bin` bytecode binary:
+//
+//   luau-compile --binary test.luau  > test.bc
+//
+// This may be required if the Luau version gets upgraded.
+
+const std = @import("std");
+
+// The ziglua module is made available in build.zig
+const ziglua = @import("ziglua");
+
+pub fn main() anyerror!void {
+    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+    const allocator = gpa.allocator();
+    defer _ = gpa.deinit();
+
+    // Initialize The Lua vm and get a reference to the main thread
+    var lua = try ziglua.Lua.init(allocator);
+    defer lua.deinit();
+
+    // Open all Lua standard libraries
+    lua.openLibs();
+
+    // Load bytecode
+    const filename = "examples/test.luau.bin";
+    const bc = std.fs.cwd().readFileAlloc(allocator, filename, std.math.maxInt(u32)) catch {
+        std.log.err("failed to open bytecode {s}", .{filename});
+        return;
+    };
+    defer allocator.free(bc);
+    try lua.loadBytecode("...", bc);
+    try lua.protectedCall(0, 0, 0);
+}

examples/test.luau

@@ -0,0 +1,13 @@
+--!strict
+
+function ispositive(x : number) : string
+    if x > 0 then
+        return "yes"
+    else
+        return "no"
+    end
+end
+
+local result : string
+result = ispositive(1)
+print("result is positive:", result)

src/zigluau/lib.zig

@@ -1143,8 +1143,14 @@ pub const Lua = struct {
 
         // luau_compile uses malloc to allocate the bytecode on the heap
         defer zig_luau_free(bytecode);
+        try lua.loadBytecode("...", bytecode[0..size]);
+    }
 
-        if (c.luau_load(lua.state, "...", bytecode, size, 0) != 0) return error.Fail;
+    /// Loads bytecode binary (as compiled with f.ex. 'luau-compile --binary')
+    /// See https://luau-lang.org/getting-started
+    /// See also condsiderations for binary bytecode compatibility/safety: https://github.com/luau-lang/luau/issues/493#issuecomment-1185054665
+    pub fn loadBytecode(lua: *Lua, chunkname: [:0]const u8, bytecode: []const u8) !void {
+        if (c.luau_load(lua.state, chunkname.ptr, bytecode.ptr, bytecode.len, 0) != 0) return error.Fail;
     }
 
     /// If the registry already has the key `key`, returns an error