_VERSION A global variable (not a function) that holds a string containing the running Lua version. The current value of this variable is "Lua 5.3".

_G§2.2

xpcall (f, msgh [, arg1, ···]) This function is similar to pcall, except that it sets a new message handler msgh.

2.5.2 – Weak Tables A weak table is a table whose elements are weak references. A weak reference is ignored by the garbage collector. In other words, if the only references to an object are weak references, then the garbage collector will collect that object. A weak table can have weak keys, weak values, or both. A table with weak values allows the collection of its values, but prevents the collection of its keys. A table with both weak keys and weak values allows the collection of both keys

utf8.offset (s, n [, i])nsiniin#s + 1utf8.offset(s, -n)nnil As a special case, when n is 0 the function returns the start of the encoding of the character that contains the i-th byte of s. This function assumes that s is a valid UTF-8 string.

utf8.len (s [, i [, j]])sijij

utf8.codes (s) Returns values so that the construction for p, c in utf8.codes(s) do body end will iterate over all characters in string s, with p being the position (in bytes) and c the code point of each character. It raises an error if it meets any invalid byte sequence.

utf8.codepoint (s [, i [, j]])sijiji

utf8.charpattern[\0-\x7F\xC2-\xF4][\x80-\xBF]*§6.4.1

utf8.char (···)