-ec ::= [~\]\\\-\~] | escaped
-
-alternatives ::= EquiAlt +/ (ws ">" ws)
-EquiAlt ::= Conjuncts +/ "|" => "alternatives"
-
-sequence ::= Es
- > Es ^"/" E /ws
-Es ::= E+
-//es ::= E+/ws
-
-Conjuncts ::= rewrite
- | rewrite ^"&" sequence
- | rewrite ^"&~" sequence
-
-rewrite ::= sequence /ws => "rewrite"
- | sequence ^"=>" word /ws
- | sequence ^"=>" quoted /ws
- | sequence "=>" "()" /ws => "wrap"
-
-range ::= ec => "range0" | ec ^"-" ec => "range0"
-E ::= word => "nonTerminalY"
- | [(][)] => "epsilon"
- | ^"{" alternatives "}"
- | "[" [\~]? range* "]" => "range"
- | E ^"*/" E
- | E ^"+/" E
- | E ^"?"
- | E ^"~/~"
-
- | E ^"-" E
-
- | ^"!" E
- | "^" quoted => "care"
- | ^"`" E
- | E ^"#"
- | quoted => "literal"
+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"
+psy ::= ps
+ | ps wp ^"/" ws e
+psx ::= psy ^"?=>" e /ws
+ | psy ^"!=>" e /ws
+ > psy
+sequence ::= quoted => "qprod"
+ > psx
+ | psx ^"=>" (word|quoted) /ws