luaL_checkudata[-0, +0, v] void *luaL_checkudata (lua_State *L, int arg, const char *tname); Checks whether the function argument arg is a userdata of the type tname (see luaL_newmetatable) and returns the userdata address (see lua_touserdata).

lua_checkstack[-0, +0, –] int lua_checkstack (lua_State *L, int n); Ensures that the stack has space for at least n extra slots (that is, that you can safely push up to n values into it). It returns false if it cannot fulfill the request, either because it would cause the stack to be larger than a fixed maximum size (typically at least several thousand elements) or because it cannot allocate memory for the extra space. This function never shrinks the stack; if the stack already has space for

lua_setuservalue[-1, +0, –] void lua_setuservalue (lua_State *L, int index); Pops a value from the stack and sets it as the new value associated to the full userdata at the given index.

package.searchers A table used by require to control how to load modules. Each entry in this table is a searcher function. When looking for a module, require calls each of these searchers in ascending order, with the module name (the argument given to require) as its sole parameter. The function can return another function (the module loader) plus an extra value that will be passed to that loader, or a string explaining why it did not find that module (or nil if it has nothing to say). Lu

lua_Writer typedef int (*lua_Writer) (lua_State *L, const void* p, size_t sz, void* ud); The type of the writer function used by lua_dump. Every time it produces another piece of chunk, lua_dump calls the writer, passing along the buffer to be written (p), its size (sz), and the data parameter supplied to lua_dump. The writer returns an error code: 0 means no errors; any other value means an error and stops lua

table.sort (list [, comp]) Sorts list elements in a given order, in-place, from list[1] to list[#list]. If comp is given, then it must be a function that receives two list elements and returns true when the first element must come before the second in the final order (so that, after the sort, i < j implies not comp(list[j],list[i])). If comp is not given, then the standard Lua operator < is used instead. Note that the comp function must define a strict partial order over the elements

3.4.11 – Function Definitions The syntax for function definition is functiondef ::= function funcbody funcbody ::= ‘(’ [parlist] ‘)’ block end The following syntactic sugar simplifies function definitions: stat ::= function funcname funcbody stat ::= local function Name funcbody funcname ::= Name {‘.’ Name} [‘:’ Name] The statement function f () body end translates to f = function () body end The statement function t.a.b.c.f () body end translates to t.a.b.c.f = function () body end

rawset (table, index, value)table[index]value__newindextableindexnilvalue This function returns table.

lua_toboolean[-0, +0, –] int lua_toboolean (lua_State *L, int index); Converts the Lua value at the given index to a C boolean value (0 or 1). Like all tests in Lua, lua_toboolean returns true for any Lua value different from false and nil; otherwise it returns false. (If you want to accept only actual boolean values, use lua_isboolean to test the value's type.)

lua_xmove[-?, +?, –] void lua_xmove (lua_State *from, lua_State *to, int n); Exchange values between different threads of the same state. This function pops n values from the stack from, and pushes them onto the stack to.