tests/meta.g

   1 s             =  ws! Grammar ws!
   2
   3 Grammar       =  NonTerminal +/ ws
   4
   5 NonTerminal   =  Word "=" RHS /ws
   6
   7 // use 'a'-'z' or 'a-z' instead of [a-z]?
   8 // EOF token?
   9 // #include (with renaming?)
  10
  11 RHS           =  (Sequence +/ (ws! "|" ws!)) +/ (ws! ">" ws!)
  12
  13 Elements      =  e*/ws
  14
  15 PreSequence   =  PS
  16               |  (Quoted|Word)   ^"::" PreSequence /ws
  17               >  PreSequence     ^"/"      e       /ws
  18               |  PreSequence     ^"->"     e       /ws
  19 PS            = Elements
  20
  21 Sequence      = psx:: PreSequence
  22               |       Sequence ^"&"  PS /ws
  23               |       Sequence ^"&~" PS /ws
  24
  25 ec            = ~[\-\]\\]
  26               | escaped
  27
  28 Range         = ec
  29               | ec ^"-" ec
  30
  31 e             =                (Quoted|Word) ^":" e
  32               >                NonTerminalReference
  33               |                Literal
  34               |                  ^"()"
  35               |                  ^"{" PreSequence "}"    /ws
  36               |                  ^"["  Range* "]"
  37               |                e ^"++"                   /ws -> ~[/]
  38               |                e ^"+"                    /ws -> ~[+]
  39               |                e ^"++/" e                /ws
  40               |                e ^"+/"  e                /ws
  41               |                e ^"**"                   /ws -> ~[/]
  42               |                e ^"*"                    /ws -> ~[*]
  43               |                e ^"**/" e                /ws
  44               |                e ^"*/"  e                /ws
  45               |                     e ^"!"
  46               |                e ^"?"                    /ws
  47               |                  ^"^"   Quoted
  48               >                  ^"(" RHS  ")"           /ws
  49               |                  ^"~" e
  50
  51 NonTerminalReference = Word
  52 Literal              = Quoted
  53 Word                 = [a-zA-Z0-9_]++
  54 Quoted               = "\"" ((~[\"\\] | escaped)+) "\""
  55                      | ""::   "\"\""
  56
  57 escaped    = "\n":: "\\n"
  58            | "\r":: "\\r"
  59            |        "\\" ~[nr]
  60
  61 w             = " " | "\n" | "\r"
  62 ws            =  "()":: w**
  63               |  "()":: w** "//" (~[\n])* "\n" ws
  64 wp            =  w++