It`s proposed grammar(Byson) for ( Lua 5 Light, may be ), in style @Lua 5.1 Reference Manual@
1 chunk: laststat
2 | stat;
3 block_ended: laststat
4 | stat_w_end;
6 stat_w_end: stat "end";
7 laststat: stat "return" args
8 | stat "return"
9 | stat "break" "`[integral const]`"
10 | stat "break"
11 | stat "error" args;
12 function_def: "function" '(' parlist ')' block_ended
14 | '\\' parlist '\\' block_ended;
16 parlist: /* empty */
17 | "`...`"
18 | namelist '|' "`...`"
19 | namelist '|' Name
20 | namelist;
21 namelist: namelist ',' Name
22 | Name;
23 stat: /* empty */
24 | "use" varlist // Lua: local sin, cos = math.sin, math.cos; Lua5L: use math.sin, math.cos
25 | stat "if" if_unmatched "else" block_ended
27 | stat "if" if_unmatched "end"
28 | stat "loop" stat_w_end // Lua: "while" "true" stat_w_end
29 | stat "while" exp stat_w_end
30 | stat "for" namelist '=' explist stat_w_end
// Lua: for i=1,50 do...; for i=1,20,3 do...; for k,v in pair(t) do...
// Lua5L{as Clu, w/o 'in' & 'do'}:
// for i = from_to(1,50) ... for i = from_to_by(1,20,3) ... for k,v = pair(t) ...
31 | stat "repeat" stat "until" exp
32 | stat '#' varlist '|' var '=' explist
33 | stat '#' varlist '=' explist
34 | stat '?' function_call
35 | stat "local" namelist
36 | stat "local" namelist '|' Name '=' explist
37 | stat "local" namelist '=' explist
38 | stat "do" block_ended
40 | stat "yield" args
41 | stat "yield";
43 if_unmatched: if_unmatched "elseif" if_unmatched
44 | exp "then" chunk;
46 varlist: varlist ',' var
47 | var;
48 bracket: '(' exp ')'
49 var: Name
50 | "self"
51 | bracket var_omega
52 | var var_omega
53 | function_call var_omega;
54 var_omega: '[' exp ']'
55 | ": identifier"; // Lua: ('.' Name) / (':' Name), Lua5L: Name:Name.Name <- may be
56 function_call: bracket args
57 | var args
58 | function_call args;
59 args: '(' explist ')'
60 | '(' ')'
61 | '{' fieldlist '}'
62 | '{' '}'
63 | String
64 | "`[integral const]`"
65 | "`[const object]`"; // nil, false, true, number
66 explist: explist ',' exp
67 | exp;
68 exp: _expression_
70 | exp '`' var '`' exp /* 0 */ // Lua: var '(' exp ',' exp ')'
71 | exp "`or`" exp /* 1 */
72 | exp "`xor`" exp /* 1 */
73 | exp "`and`" exp; /* 2 */
74 _expression_: _expression_ "`==`" _expression_ /* 3, %nonassoc */
75 | _expression_ "`~=`" _expression_ /* 3, %nonassoc */
76 | _expression_ '>' _expression_ /* 3, %nonassoc */
77 | _expression_ '<' _expression_ /* 3, %nonassoc */
78 | _expression_ "`<=`" _expression_ /* 3, %nonassoc */
79 | _expression_ "`>=`" _expression_ /* 3, %nonassoc */
80 | _expression_ "`..`" _expression_ /* 4, %right */
81 | _expression_ '+' _expression_ /* 5 */
82 | _expression_ '-' _expression_ /* 5 */
83 | _expression_ '*' _expression_ /* 6 */
84 | _expression_ '/' _expression_ /* 6 */
85 | _expression_ '%' _expression_ /* 6 */
86 | '-' _expression_ /* 7 */
87 | '+' _expression_ /* 7 */
88 | '!' _expression_ /* 7 */
89 | _expression_ '^' _expression_ /* 8,%right */
90 | '$' _expression_ /* 9 */ // {len} Lua: #exp
91 | const_exptession
92 | function_def
93 | bracket
94 | function_call
95 | var
96 | "`...`";
97 const_exptession: '{' fieldlist '}'
98 | '{' '}'
99 | String
100 | "`[integral const]`"
101 | "`[const object]`";
102 fieldlist: fieldlist ',' fieldlist
103 | '[' exp ']' '=' exp
104 | Name '=' exp
105 | exp;
A rhetorical question about: is it really necessary? - not accept. Its longe, boring question, and not rhetorical answer.
The question: Have You interesting idea about Lua syntax?
PS: PEG released, its no problem.
