-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 ws ^"/" e
-es ::= e */ (w**)
-
-ss ::= es | es ^"/" e /ws
-
-conjuncts ::= rewrite
- | rewrite ^"&" e*/ws /ws
- | rewrite ^"&~" e*/ws /ws
-
-rewrite ::= sequence /ws => "rewrite"
- | sequence ^"=>" word /ws
- | sequence ^"=>" quoted /ws
- | sequence "=>" "()" /ws => "wrap"
-
-ec ::= [~\-\]\\\~]
- | escaped
-
-range ::= ec => "range"
- | ec ^"-" ec
-
-e ::= word => "nonTerminalY"
- | [(][)] => "epsilon"
- | ^"{" alternatives "}" /ws
- | ^"[" (range*) "]"
- | ^"[~" (range*) "]"
- | e ^"+/" e /ws
- | e ^"*/" e /ws
- | e ^"?" /ws
- | e ^"~/~" /ws
-
- | e ^"-" e /ws
-
- | ^"!" e /ws
- | ^"^" quoted /ws
- | ^"`" e /ws
- | e ^"#" /ws
- | quoted => "literal"
-
- | (e ws ^"**" > e ws ^"*")
- | (e ws ^"++" > e ws ^"+")
-
- | "(" word ^")" /ws
- > ^"(" alternatives ")" /ws
-
-w !::= " "
- | "//" ([~\n]*) "\n"
- | "\n"
- | "\r"
-an ::= [a-zA-Z0-9_]
-word ::= an++ => "sify"
-quoted ::= "\"" (([~\"\\] | escaped)*) "\"" => "sify"
-escaped ::= "\\n" => "\n"
- | "\\r" => "\r"
- | "\\" [~nr]
-
-
+s = ws gram:Grammar ws
+Grammar = grammar:: NonTerminal +/ ws
+NonTerminal = word !wp ^"=" !wp RHS
+
+RHS = (Sequence +/ (!ws "|" !ws)) +/ (!ws ">" !ws)
+
+Elements = e*/ws
+
+PreSequence = ps:: Elements
+ | PreSequence !wp ^"/" !ws e
+ | PreSequence ^"->" e /ws
+ | (Quoted|word) ^"::" PreSequence /ws
+
+Sequence = psx:: PreSequence
+ | Sequence !ws ^"&" !ws Elements
+ | Sequence !ws ^"&~" !ws Elements
+
+ec = ~[\-\]\\]
+ | escaped
+
+Range = range:: ec
+ | ec ^"-" ec
+
+e = (Quoted|word) ^":" e
+ > nonTerminal:: word
+ | literal:: Quoted
+ | ^"()"
+ | ^"{" Sequence "}" /ws
+ | ^"[" Range* "]"
+ | e ^"++" /ws -> ~[/]
+ | e ^"+" /ws -> ~[+]
+ | e ^"++/" e /ws
+ | e ^"+/" e /ws
+ | e ^"**" /ws -> ~[/]
+ | e ^"*" /ws -> ~[*]
+ | e ^"**/" e /ws
+ | e ^"*/" e /ws
+ | ^"!" e /ws
+ | e ^"?" /ws
+ | ^"^" Quoted
+ | "(" word ^")" /ws
+ > ^"(" RHS ")" /ws
+ | ^"~" e
+ > "^^":: "^" e
+
+word = [a-zA-Z0-9_]++
+Quoted = "\"" ((~[\"\\] | escaped)+) "\""
+ | "":: "\"\""
+escaped = "\n":: "\\n"
+ | "\r":: "\\r"
+ | "\\" ~[nr]
+
+
+w = " " | "\n" | "\r"
+ws = "()":: w**
+ | "()":: w** "//" ~[\n]* "\n" ws
+wp = w++