#lang yaragg ;; Lua parser, adapted from: ;; http://www.lua.org/manual/5.1/manual.html#8 ;; chunk : (stat ["; "])* [laststat ["; "]] block : chunk stat : varlist "=" explist | functioncall | 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] laststat : RETURN [explist] | BREAK funcname : NAME ("." NAME)* [":" NAME] varlist : var ("," var)* var : NAME | prefixexp "[" exp "]" | prefixexp "." NAME namelist : NAME ("," NAME)* explist : (exp ",")* exp ;; Note by dyoo: The parsing of exp deviates from Lua in that we have these administrative ;; rules to explicitly represent the precedence rules. ;; ;; See: http://www.lua.org/manual/5.1/manual.html#2.5.6 ;; ;; Ragg doesn't yet automatically desugar operator precedence rules. ;; I'm doing it by hand at the moment, which is not ideal, so a future version of ;; ragg will have a story about describing precedence. ;; ;; Operator precedence in Lua follows the table below, from lower to higher priority: ;; ;; or exp_1 ;; and exp_2 ;; < > <= >= ~= == exp_3 ;; .. exp_4 ;; + - exp_5 ;; * / % exp_6 ;; not # - (unary) exp_7 ;; ^ exp_8 ;; ;; As usual, you can use parentheses to change the precedences of an expression. ;; The concatenation ('..') and exponentiation ('^') operators are right associative. ;; All other binary operators are left associative. ;; ;; The original grammar rule before encoding precedence was: ;; ;; exp : NIL | FALSE | TRUE | NUMBER | STRING | "..." | function | ;; prefixexp | tableconstructor | exp binop exp | unop exp exp : exp_1 exp_1: exp_1 binop_1 exp_2 | exp_2 exp_2: exp_2 binop_2 exp_3 | exp_3 exp_3: exp_3 binop_3 exp_4 | exp_4 exp_4: exp_5 binop_4 exp_4 | exp_5 ;; right associative exp_5: exp_5 binop_5 exp_6 | exp_6 exp_6: exp_6 binop_6 exp_7 | exp_7 exp_7: unop exp_8 exp_8: exp_9 binop_8 exp_8 | exp_9 ;; right associative exp_9: NIL | FALSE | TRUE | NUMBER | STRING | "..." | function | prefixexp | tableconstructor binop_1: OR binop_2: AND binop_3: "<" | ">" | "<=" | ">=" | "~=" | "==" binop_4: ".." binop_5: "+" | "-" binop_6: "*" | "/" | "%" binop_8: "^" ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; prefixexp : var | functioncall | "(" exp ")" functioncall : prefixexp args | prefixexp ":" NAME args args : "(" [explist] ")" | tableconstructor | STRING function : 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 | "#"