1 s ::= ws grammar ws => "gram"
3 grammar ::= r +/ ws => "grammar"
4 r ::= word ^"::=" alternatives /ws
5 | word ^"!::=" alternatives /ws
7 alternatives ::= equiAlt +/ (ws ">" ws)
8 equiAlt ::= conjuncts +/ (ws "|" ws)
11 | rewrite ^"&" e*/ws /ws
12 | rewrite ^"&~" e*/ws /ws
14 sequence ::= e*/ws (ws "/" e)? => "seq"
16 rewrite ::= sequence /ws => "rewrite"
17 | sequence ^"=>" (word|quoted) /ws
22 range ::= ec => "range"
25 e ::= word => "nonTerminal"
27 | ^"{" alternatives "}" /ws
33 | (e ws ^"**" > e ws ^"*")
35 | (e ws ^"++" > e ws ^"+")
42 > ^"(" alternatives ")" /ws
50 quoted ::= "\"" (([~\"\\] | escaped)+) "\""
52 escaped ::= "\\n" => "\n"