1 s = !ws Grammar ws => "gram"
2 Grammar = NonTerminal +/ ws => "grammar"
3 NonTerminal = word !wp ^"=" !wp RHS
5 RHS = (Conjuncts +/ (!ws "|" !ws)) +/ (!ws ">" !ws)
8 | Sequence ^"&" Elements /ws
9 | Sequence ^"&~" Elements /ws
12 PreSequence = Elements => "ps"
13 | PreSequence !wp ^"/" !ws e
14 | PreSequence ^"->" e /ws
15 | (Quoted|word) ^"::" PreSequence /ws
16 | PreSequence ^"=>" ("[]"|"()"|word|Quoted) /ws
17 Sequence = PreSequence => "psx"
27 > word => "nonTerminal"
30 | ^"{" Sequence "}" /ws
49 Quoted = "\"" ((~[\"\\] | escaped)+) "\""
51 escaped = "\\n" => "\n"
58 | w** "//" ~[\n]* "\n" ws => ()