Lua 5.3 Reference Manual
by Roberto Ierusalimschy, Luiz Henrique de Figueiredo, Waldemar CelesCopyright © 2015–2018 Lua.org, PUC-Rio. Freely available under the terms of the Lua license.
The Complete Syntax of Lua
Here is the complete syntax of Lua in extended BNF. As usual in extended BNF, {A} means 0 or more As, and [A] means an optional A. (For operator precedences, see Precedence; for a description of the terminals Name, Numeral, and LiteralString, see Lexical Conventions.)
chunk ::= block block ::= {stat} [retstat] stat ::= ';' | varlist '=' explist | functioncall | label | break | goto Name | do block end | while exp do block end | repeat block until exp | if exp then block {elseif exp then block} [else block] end | for Name '=' exp ',' exp [',' exp] do block end | for namelist in explist do block end | function funcname funcbody | local function Name funcbody | local namelist ['=' explist] retstat ::= return [explist] [';'] label ::= '::' Name '::' funcname ::= Name {'.' Name} [':' Name] varlist ::= var {',' var} var ::= Name | prefixexp '[' exp ']' | prefixexp '.' Name namelist ::= Name {',' Name} explist ::= exp {',' exp} exp ::= nil | false | true | Numeral | LiteralString | '...' | functiondef | prefixexp | tableconstructor | exp binop exp | unop exp prefixexp ::= var | functioncall | '(' exp ')' functioncall ::= prefixexp args | prefixexp ':' Name args args ::= '(' [explist] ')' | tableconstructor | LiteralString functiondef ::= function funcbody funcbody ::= '(' [parlist] ')' block end parlist ::= namelist [',' '...'] | '...' tableconstructor ::= '{' [fieldlist] '}' fieldlist ::= field {fieldsep field} [fieldsep] field ::= '[' exp ']' '=' exp | Name '=' exp | exp fieldsep ::= ',' | ';' binop ::= '+' | '-' | '*' | '/' | '//' | '^' | '%' | '&' | '~' | '|' | '>>' | '<<' | '..' | '<' | '<=' | '>' | '>=' | '==' | '~=' | and | or unop ::= '-' | not | '#' | '~'