Given a lua file like
-- foo.lua
return function (i)
return i
end
How can I load this file with the C API and call the returned function?
I just need function calls beginning with luaL_loadfile/luaL_dostring.
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1 Answer
A loaded chunk is just a regular function. Loading the module from C can be thought of like this:
return (function() -- this is the chunk compiled by load
-- foo.lua
return function (i)
return i
end
end)() -- executed with call/pcall
All you have to do is load the chunk and call it, its return value is your function:
// load the chunk
if (luaL_loadstring(L, script)) {
return luaL_error(L, "Error loading script: %s", lua_tostring(L, -1));
}
// call the chunk (function will be on top of the stack)
if (lua_pcall(L, 0, 1, 0)) {
return luaL_error(L, "Error running chunk: %s", lua_tostring(L, -1));
}
// call the function
lua_pushinteger(L, 42); // function arg (i)
if (lua_pcall(L, 1, 1, 0)) {
return luaL_error(L, "Error calling function: %s", lua_tostring(L, -1));
}
1 Comment
Sebastian Graf
Ahh, thanks, that's a really helpful semantic of 'chunk'. Actually, one of the versions I've tried so far was similar, only that I my first call was
lua_pcall(L, 0, 0), which discarded the result. That left me wondering why there was no return value.