| sequence ^"&" e*/ws /ws
| sequence ^"&~" e*/ws /ws
-sequence ::= e*/ws
- (ws "/" e)?
- (ws "=>" ws (word|quoted))? => "seq"
+ps ::= (e*/ ws) => "ps"
+psx ::= ps
+ | ps ws ^"/" e
+sequence ::= psx
+ (ws "=>" ws (word|quoted))? => "seqx"
ec ::= [~\-\]\\\~]
| escaped