-s ::= ws grammar ws => "gram"
-ws !::= w**
-grammar ::= r +/ ws => "grammar"
-
-r ::= word ^"::=" alternatives /ws
- | word ^"!::=" alternatives /ws
-
-alternatives ::= (conjuncts +/ (ws "|" ws)) +/ (ws ">" ws)
-
-conjuncts ::= sequence
- | sequence ^"&" e*/ws /ws
- | sequence ^"&~" e*/ws /ws
-
-ps ::= e*/ws => "ps"
- | (e+/ws ws)? "^" quoted (ws e+/ws)? => "ps2"
-psx ::= ps
- > ps ^"/" e /ws
-sequence ::= psx
- | psx ^"=>" (word|quoted) /ws
-
-ec ::= [~\-\]\\\~]
- | escaped
-
-range ::= ec => "range"
- | ec ^"-" ec
-
-e ::= word => "nonTerminal"
- | quoted => "literal"
- | ^"()"
- | ^"{" sequence "}" /ws
- | ^"[" range* "]"
- | ^"[~" range* "]"
-
- | (e ws ^"**" > e ws ^"*")
- | e ^"*/" e /ws
- | (e ws ^"++" > e ws ^"+")
- | e ^"+/" e /ws
- | e ^"?" /ws
-
- | "(" word ^")" /ws
- > ^"(" alternatives ")" /ws
-w !::= " "
- | "//" ([~\n]*) "\n"
- | "\n"
- | "\r"
-word ::= [a-zA-Z0-9_]++
-quoted ::= "\"" (([~\"\\] | escaped)+) "\""
- | "\"\"" => ""
-escaped ::= "\\n" => "\n"
- | "\\r" => "\r"
- | "\\" [~nr]
-
-
+s = !ws (grammar::Grammar) !ws
+
+Grammar = NonTerminal +/ ws
+
+NonTerminal = Word ^"=" RHS /ws
+
+// use 'a'-'z' or 'a-z' instead of [a-z]?
+// EOF token?
+// #include (with renaming?)
+// ANTLR uses ! and ^ suffixes
+
+RHS = (Sequence +/ (!ws "|" !ws)) +/ (!ws ">" !ws)
+
+Elements = e*/ws
+
+PreSequence = ps:: Elements
+ | (Quoted|Word) ^"::" PreSequence /ws
+ > PreSequence ^"/" e /ws
+ | PreSequence ^"->" e /ws
+
+Sequence = psx:: PreSequence
+ | Sequence ^"&" Elements /ws
+ | Sequence ^"&~" Elements /ws
+
+ec = ~[\-\]\\]
+ | escaped
+
+Range = range:: ec
+ | ec ^"-" ec
+
+e = (Quoted|Word) ^":" e
+ > nonTerminal:: Word
+ | literal:: Quoted
+ | ^"()"
+ | ^"{" PreSequence "}" /ws
+ | ^"[" Range* "]"
+ | e ^"++" /ws -> ~[/]
+ | e ^"+" /ws -> ~[+]
+ | e ^"++/" e /ws
+ | e ^"+/" e /ws
+ | e ^"**" /ws -> ~[/]
+ | e ^"*" /ws -> ~[*]
+ | e ^"**/" e /ws
+ | e ^"*/" e /ws
+ | ^"!" e /ws
+ | e ^"?" /ws
+ | ^"^" Quoted
+ | "(" Word ^")" /ws
+ > ^"(" RHS ")" /ws
+ | ^"~" e
+ > "^^":: "^" e
+
+Word = [a-zA-Z0-9_]++
+Quoted = "\"" ((~[\"\\] | escaped)+) "\""
+ | "":: "\"\""
+escaped = "\n":: "\\n"
+ | "\r":: "\\r"
+ | "\\" ~[nr]
+
+w = " " | "\n" | "\r"
+ws = "()":: w**
+ | "()":: w** "//" (~[\n])* "\n" ws
+wp = w++