tests/meta.g

   1 s         ::=  ws grammar ws                  => "gram"
   2 ws       !::=  w**
   3 grammar   ::=  r +/ ws                        => "grammar"
   4 r         ::=  word  ^"::=" alternatives /ws
   5             |  word ^"!::=" alternatives /ws
   6
   7 alternatives  ::=  (conjuncts +/ (ws "|" ws)) +/ (ws ">" ws)
   8
   9 conjuncts   ::=  sequence
  10               |  sequence ^"&"  e*/ws   /ws
  11               |  sequence ^"&~" e*/ws   /ws
  12
  13 sequence    ::= e*/ws
  14                 (ws "/" e)?
  15                 (ws "=>" ws (word|quoted))?              => "seq"
  16
  17 ec       ::= [~\-\]\\\~]
  18            | escaped
  19
  20 range    ::= ec          => "range"
  21            | ec ^"-" ec
  22
  23 e        ::=  word                          => "nonTerminal"
  24            |  quoted                        => "literal"
  25            |    ^"()"
  26            |    ^"{" sequence "}"       /ws
  27            |    ^"["  (range*) "]"
  28            |    ^"[~" (range*) "]"
  29            |    ^"^" quoted             /ws
  30            |    ^"!" e                  /ws
  31
  32            |  (e ws ^"**" > e ws ^"*")
  33            |  e ^"*/" e                 /ws
  34            |  (e ws ^"++" > e ws ^"+")
  35            |  e ^"+/" e                 /ws
  36            |  e ^"?"                    /ws
  37
  38            |     "(" word         ^")"  /ws
  39            >    ^"(" alternatives  ")"  /ws
  40
  41 w       !::= " "
  42            | "//" ([~\n]*) "\n"
  43            | "\n"
  44            | "\r"
  45 word     ::= [a-zA-Z0-9_]++
  46 quoted   ::= "\"" (([~\"\\] | escaped)+) "\""
  47            | "\"\"" => ""
  48 escaped  ::= "\\n" => "\n"
  49            | "\\r" => "\r"
  50            | "\\" [~nr]
  51
  52