CODEWITHSUNDEEP
lua
Sven Nilsson
Sven Nilsson

Reputation: 1869

I have a table on the Lua stack. How can I push a function on the stack that returns this table?

Using the C API, I have pushed a table on the Lua stack. How can I push a function on the stack that returns this table?

The closest I can find is lua_pushcclosure, but that pushes a lua_CFunction on the stack, not a real Lua function, and that is not acceptable in my case because I want to use setfenv later, which only works with real Lua functions.

Regards

Upvotes: 2

Views: 1081

Answers (2)

Sven Nilsson
Sven Nilsson

Reputation: 1869

Old question, but I now add the correct answer as suggested by Etan.

status = luaL_dostring(L, "return function (ppp) return function () return ppp end end");
if (!status) {
    // push table here
    status = lua_pcall(L, 1, LUA_MULTRET, 0);
}

Regarding the question making no sense, I am aware that setfenv has no effect.

My only requirement was that setfenv can be executed without causing a crash.

Upvotes: 0

Nicol Bolas
Nicol Bolas

Reputation: 473322

Well, you do the obvious. Since it must be a "real Lua function", you must create a real Lua function that returns the table.

Something like this:

local tbl = ...
return function() return tbl end

This is a Lua chunk that, when executed, will return a function that returns the first parameter the original chunk was called with.

So simply use luaL_loadstring to load that string. Call the resulting chuck with your table; the return value will be the function you desire.

That being said, your question ultimately makes no sense. setfenv will not accomplish anything of value here. Setting the environment of a function that returns a local table will not affect anything stored within that table.

Upvotes: 0

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