9 Lua の完全な構文

Lua の完全な構文を拡張 BNF で示します。普通の拡張 BNF と同様に、{A} は 0 個以上の A を表し、[A] は省略可能な A を表します。演算子の優先順位については § 3.4.8 を、終端記号 Name, Numeral, LiteralString については § 3.1 を参照してください。

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 attnamelist [‘=’ explist] 

attnamelist ::= Name attrib {‘,’ Name attrib}

attrib ::= [‘<’ Name ‘>’]

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 | ‘#’ | ‘~’