-s ::= ws grammar ws => "gram"
-ws !::= w**
-grammar ::= r $$ ws => "grammar"
-r ::= word ^"::=" alternatives /ws
- | word ^"!::=" alternatives /ws
-
-alternatives ::= equiAlt $$ (ws ">" ws)
-equiAlt ::= conjuncts $$ (ws "|" ws) => "alternatives"
-
-sequence ::= Es
- > Es ^"/" e /ws
-Es ::= e+
-es ::= e %% ws
-
-ss ::= es | es ^"/" e /ws
-
-conjuncts ::= rewrite
- | rewrite ^"&" e%%ws /ws
- | rewrite ^"&~" e%%ws /ws
-
-rewrite ::= sequence /ws => "rewrite"
- | sequence ^"=>" word /ws
- | sequence ^"=>" quoted /ws
- | sequence "=>" "()" /ws => "wrap"
-
-ec ::= [~\-\]\\\~]
+s ::= Grammar ws => "gram"
+Grammar ::= NonTerminal +/ ws => "grammar"
+NonTerminal ::= word ^"::=" RHS /ws
+
+w ::= " " | "\n" | "\r"
+ws ::= w** => ()
+ | w** "//" ~[\n]* "\n" ws => ()
+wp ::= w++
+
+RHS ::= (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)?
+psy ::= ps
+ | ps !wp ^"/" !ws e
+psx ::= psy => "psy"
+ | psy ^"->" e /ws
+Sequence ::= Quoted => "qprod"
+ > psx => "psx"
+ | psx "=>" ^"[]" /ws
+ | psx ^"=>" ("()"|word|Quoted) /ws
+
+ec ::= ~[\-\]\\]