PEG.js parser for custom headers (for Restful applications). https://github.com/joinbox/guidelines/blob/master/styleguide/RESTful.md

Custom-Header-Grammar

{
  var argumentsList = function(first, more){
    var sg = [first];
    for(var i=0; i<more.length; i++){
      sg.push(more[i][1]);
    } 
    return sg;
  };
}

start = comp
dot = '.'
comma = full:(ws ',' ws) {return full[1]}
sq = "'"
dq = '"'
ws = (blank / "\n") * {return ""; }
blank = " " / "\t"

name_base = chars:([A-Z_]i[A-Z0-9_]i*) {return chars[0]+chars[1].join(""); }
name = base:name_base !'(' { return base }
name_dotted = name (dot name)*
name_tagged = result:(name_dotted ws name_tag) {return [result.shift(), result.pop()]; }
name_tag = name

value = function / array / date / literal / name_dotted
values = first:value more:(comma value)* { return argumentsList(first, more); }

literal = string / number / boolean / null

array = arr:(ws '[' ws array_items? ws ']' ws) {
  arr.shift();
  arr.pop();
  return [arr.shift(), arr[1], arr.pop()];
}
array_items = values

null = 'null'

boolean = boolean_true / boolean_false
boolean_true = 'true' { return true; }
boolean_false = 'false' { return false; }

number = integer / float
integer = num:[0-9]+ !dot { return parseInt(num.join(""), 10); }
float = num:([0-9]+ dot [0-9]*) { return parseFloat( num[0].join("")+num[1]+num[2].join(""), 10); }

string = str:(string_sq / string_dq) {return str[1].join(""); }
string_sq = sq string_sq_char* sq
string_sq_char = char:(('\\' sq) / (!sq .)) {return char.join(""); }

string_dq = dq string_dq_char* dq
string_dq_char = char:(('\\' dq) / (!dq .)) {return char.join(""); }

function = name_base '(' ws args:(function_arguments?) ws ')'
function_arguments = values

select = single:name_dotted more:(comma name_dotted)* { return argumentsList(single, more); }

filter = single:filter_item more:(comma filter_item)* { return argumentsList(single, more); }
filter_item = name_dotted

order = single:order_item more:(comma order_item)* { return argumentsList(single, more); }
order_item = function / name_tagged / name_dotted

date = year:date_year '-' month:date_month '-' day:date_day ws time:date_time? {
  var hour = 0,
      min = 0,
      sec = 0;
  if(time.length){
    hour = time[0],
    min = time[2],
    sec = time[4];
  }
  return new Date(year, month, day, hour, min, sec);
}
date_two = one:[0-9]two:[0-9] {return parseInt(one+two, 10); }
date_year = result:([1-9][0-9][0-9][0-9]) {return parseInt(result.join(""), 10);}
date_month = date_two
date_day = date_two
date_time = date_two ':' date_two ':' date_two

comp = name_dotted comp_op value
comp_op = ws op:('!=' / '=' / '>=' / '<=' / '>' / '<') ws { return op; }