1 s ::= ws grammar ws => "gram"
3 grammar ::= r +/ ws => "grammar"
4 r ::= word ^"::=" alternatives /ws
5 | word ^"!::=" alternatives /ws
7 alternatives ::= (conjuncts +/ (ws "|" ws)) +/ (ws ">" ws)
10 | sequence ^"&" e*/ws /ws
11 | sequence ^"&~" e*/ws /ws
15 (ws "=>" ws (word|quoted))? => "seq"
20 range ::= ec => "range"
23 e ::= word => "nonTerminal"
26 | ^"{" sequence "}" /ws
32 | (e ws ^"**" > e ws ^"*")
34 | (e ws ^"++" > e ws ^"+")
39 > ^"(" alternatives ")" /ws
45 word ::= [a-zA-Z0-9_]++
46 quoted ::= "\"" (([~\"\\] | escaped)+) "\""
48 escaped ::= "\\n" => "\n"