math.randomseed (x) Sets x as the "seed" for the pseudo-random generator: equal seeds produce equal sequences of numbers.

lua_rotate[-0, +0, –] void lua_rotate (lua_State *L, int idx, int n); Rotates the stack elements between the valid index idx and the top of the stack. The elements are rotated n positions in the direction of the top, for a positive n, or -n positions in the direction of the bottom, for a negative n. The absolute value of n must not be greater than the size of the slice being rotated. This function cannot be called with a pseudo-index, because a pseudo-index is not an actual stack position.

math.ult (m, n) Returns a boolean, true if and only if integer m is below integer n when they are compared as unsigned integers.

lua_KContext typedef ... lua_KContext; The type for continuation-function contexts. It must be a numeric type. This type is defined as intptr_t when intptr_t is available, so that it can store pointers too. Otherwise, it is defined as ptrdiff_t.

3.4.2 – Bitwise Operators Lua supports the following bitwise operators: &: bitwise AND |: bitwise OR ~: bitwise exclusive OR >>: right shift <<: left shift ~: unary bitwise NOT All bitwise operations convert its operands to integers (see §3.4.3), operate on all bits of those integers, and result in an integer. Both right and left shifts fill the vacant bits with zeros. Negative displacements shift to the other direction; displacements with absolute values equal to o

file:read (···) Reads the file file, according to the given formats, which specify what to read. For each format, the function returns a string or a number with the characters read, or nil if it cannot read data with the specified format. (In this latter case, the function does not read subsequent formats.) When called without formats, it uses a default format that reads the next line (see below). The available formats are "n": reads a numeral and returns it as a float or an integer, fol

lua_tointegerx[-0, +0, –] lua_Integer lua_tointegerx (lua_State *L, int index, int *isnum); Converts the Lua value at the given index to the signed integral type lua_Integer. The Lua value must be an integer, or a number or string convertible to an integer (see §3.4.3); otherwise, lua_tointegerx returns 0. If isnum is not NULL, its referent is assigned a boolean value that indicates whether the operation succeeded.

luaL_checkversion[-0, +0, v] void luaL_checkversion (lua_State *L); Checks whether the core running the call, the core that created the Lua state, and the code making the call are all using the same version of Lua. Also checks whether the core running the call and the core that created the Lua state are using the same address space.

debug.getlocal ([thread,] f, local) This function returns the name and the value of the local variable with index local of the function at level f of the stack. This function accesses not only explicit local variables, but also parameters, temporaries, etc. The first parameter or local variable has index 1, and so on, following the order that they are declared in the code, counting only the variables that are active in the current scope of the function. Negative indices refer to vararg para

io.open (filename [, mode]) This function opens a file, in the mode specified in the string mode. In case of success, it returns a new file handle. The mode string can be any of the following: "r": read mode (the default); "w": write mode; "a": append mode; "r+": update mode, all previous data is preserved; "w+": update mode, all previous data is erased; "a+": append update mode, previous data is preserved, writing is only allowed at the end of file. The mode string can also