PEG grammer for pattern match syntax. Forked from JSON grammer.

PEG grammer for pattern match syntax

JSON_text
  = ws value:value ws { return value; }

begin_array     = ws "[" ws
begin_object    = ws "{" ws
end_array       = ws "]" ws
end_object      = ws "}" ws
name_separator  = ws ":" ws
value_separator = ws "," ws

ws "whitespace" = [ \t\n\r]*

identChar = [a-zA-Z_]

ident = value:identChar+ { return value.join('') }

identifier = name:ident { return { type: "identifier", name: name } }

// ----- 3. Values -----

value
  = false
  / null
  / true
  / object
  / array
  / number
  / string

false = "false" { return false; }
null  = "null"  { return null;  }
true  = "true"  { return true;  }

// ----- 4. Objects -----

object
  = begin_object
    members:(
      head:member
      tail:(value_separator m:member { return m; })*
      {
        var entries = [];

        [head].concat(tail).forEach(function(element) {
          entries.push(element);
        });

        return { type: "object", entries: entries };
      }
    )?
    end_object
    { return members !== null ? members: {}; }

name = string
  / id:identifier "?" {
    id.optional = true;
    return id;
  }
  / identifier
  / "[" ws value:value ws "]" {return value}

member
  = name:name name_separator alias:ident ws value:value {
  console.log(name,alias,value)
    return [ name, {type: "alias", name: alias, value: value } ]
  }
  / name:name name_separator value:value {
      return [name, value];
    }
  / name:name { return name; }
  / "..." id:identifier {
    id.spread = true;
    return id;
  }


// ----- 5. Arrays -----

array
  = begin_array
    values:(
      head:value
      tail:(value_separator v:value { return v; })*
      { return [head].concat(tail); }
    )?
    end_array
    { return values !== null ? values : []; }

// ----- 6. Numbers -----

number "number"
  = minus? int frac? exp? { return parseFloat(text()); }

decimal_point
  = "."

digit1_9
  = [1-9]

e
  = [eE]

exp
  = e (minus / plus)? DIGIT+

frac
  = decimal_point DIGIT+

int
  = zero / (digit1_9 DIGIT*)

minus
  = "-"

plus
  = "+"

zero
  = "0"

// ----- 7. Strings -----

string "string"
  = quotation_mark chars:char* quotation_mark { return chars.join(""); }

char
  = unescaped
  / escape
    sequence:(
        '"'
      / "\\"
      / "/"
      / "b" { return "\b"; }
      / "f" { return "\f"; }
      / "n" { return "\n"; }
      / "r" { return "\r"; }
      / "t" { return "\t"; }
      / "u" digits:$(HEXDIG HEXDIG HEXDIG HEXDIG) {
          return String.fromCharCode(parseInt(digits, 16));
        }
    )
    { return sequence; }

escape
  = "\\"

quotation_mark
  = '"'

unescaped
  = [^\0-\x1F\x22\x5C]

// ----- Core ABNF Rules -----

// See RFC 4234, Appendix B (http://tools.ietf.org/html/rfc4234).
DIGIT  = [0-9]
HEXDIG = [0-9a-f]i