s ::= ws grammar ws => "gram" ws !::= w** grammar ::= r $$ ws => "grammar" r ::= word ^"::=" alternatives /ws | word ^"!::=" alternatives /ws alternatives ::= equiAlt $$ (ws ">" ws) equiAlt ::= conjuncts $$ (ws "|" ws) => "alternatives" sequence ::= Es > Es ^"/" e /ws Es ::= e+ es ::= e %% ws conjuncts ::= rewrite | rewrite ^"&" sequence /ws | rewrite ^"&~" sequence /ws rewrite ::= sequence /ws => "rewrite" | sequence ^"=>" word /ws | sequence ^"=>" quoted /ws | sequence "=>" "()" /ws => "wrap" ec ::= [~\-\]\\\~] | escaped range ::= ec => "range0" | ec ^"-" ec => "range1" e ::= word => "nonTerminalY" | [(][)] => "epsilon" | ^"{" alternatives "}" /ws | "[" ranges "]" => "range" | "[~" ranges "]" => "rangex" | e ^"%%" e /ws | e ^"$$" e /ws | e ^"?" /ws | e ^"~/~" /ws | e ^"-" e /ws | ^"!" e /ws | "^" quoted /ws => "care" | ^"`" e /ws | e ^"#" /ws | quoted => "literal" | (e ws ^"**" > e ws ^"*") | (e ws ^"++" > e ws ^"+") | "(" word ^")" /ws > ^"(" alternatives ")" /ws ranges ::= range* w !::= " " | "//" [~\n]* "\n" | "\n" | "\r" an ::= [a-zA-Z0-9_] word ::= an++ => "sify" quoted ::= "\"" ([~\"\\] | escaped)* "\"" => "sify" escaped ::= "\\n" => "\n" | "\\r" => "\r" | "\\" [~nr]