Method pushValue

src/type-extensions/function.ts:145–174

(thread: Thread, decoration: Decoration<FunctionType, FunctionDecoration>)

    }

    public pushValue(thread: Thread, decoration: Decoration<FunctionType, FunctionDecoration>): boolean {
        if (typeof decoration.target !== 'function') {
            return false
        }

        // It's surprisingly inefficient to map JS functions to C functions so this creates a reference to the
        // function which stays solely in JS. The cfunction called from Lua is created at the top of the class
        // and it accesses the JS data through an upvalue.

        const pointer = thread.lua.ref(decoration)
        // 4 = size of pointer in wasm.
        const userDataPointer = thread.lua.lua_newuserdatauv(thread.address, PointerSize, 0)
        thread.lua.module.setValue(userDataPointer, pointer, '*')

        if (LuaType.Nil === thread.lua.luaL_getmetatable(thread.address, this.name)) {
            // Pop the pushed userdata.
            thread.pop(1)
            thread.lua.unref(pointer)
            throw new Error(`metatable not found: ${this.name}`)
        }

        // Set as the metatable for the function.
        // -1 is the metatable, -2 is the userdata
        thread.lua.lua_setmetatable(thread.address, -2)

        // Pass 1 to associate the closure with the userdata, pops the userdata.
        thread.lua.lua_pushcclosure(thread.address, this.functionWrapper, 1)

        return true
    }

    public getValue(thread: Thread, index: number): FunctionType {
        // Create a copy of the function