PEG.js selection grammar.

grammar.peg.js

// Property based selections

{

function SelectionPredicate(selectionname)
{
    this.selectionname = selectionname;
}

function ClassPredicate(classname)
{
    this.classname = classname;

}

function Predicate(property, selector)
{
    this.property = property;
    this.selector = selector;
}

function Integer(digits) {
    return parseInt(digits.join(""), 10);
}

function Range(start, end) {
   this.start = start;
   this.end = end;
}

function Selector (value) {


   if (value instanceof Range)
   {
       this.values = {};
       this.ranges = [value];
   }
   else
   {
       this.values = {}
       this.values[value] = true;
       this.ranges = [];
   }
   
   this.join = function(other) {
       for (var attrname in other.values) { this.values[attrname] = other.values[attrname]; }

       for (var li in other.ranges) {this.ranges.push(other.ranges[li]);}

   }
   
}

}

selection =
  selection:(chaini_selection / chain_selection / residue_selection / element_selection / atom_selection / class_selection/ named_selection)
 {
    console.log(selection);
    return selection;
 }

chaini_selection "chain selection" =
 "chain" "i"? " " selector:integer_selector
  {
    return new Predicate("chaini", selector);
  }

chain_selection "chain selection" =
 "chain" "i"? " " selector:identifier_selector
  {
    return new Predicate("chain", selector);
  }

residue_selection "residue_selection" = 
 "res" ("i" "due"?)? " " selector:integer_selector
  {
    return new Predicate("residue", selector);
  }

element_selection "element selection" =
 "elem" "ent"? " " selector:identifier_selector
 {
    return new Predicate("element", selector);
 }

atom_selection "atom selection" = 
 "atom" ("n" "ame"?)? " " selector:identifier_selector
 {
    return new Predicate("atomn", selector);
 }

class_selection "class name" =
 name:("bb" / "sc")
 {
    return new ClassPredicate(name);
 }

named_selection "selection name" =
 selectionname:identifier
 {
    return new SelectionPredicate(selectionname);
 }

// Basic identifier parsers

identifier_selector
  = value:identifier next:("," identifier_selector)*
 {
    s = new Selector(value);
    if(next.length > 0)
    {
        next_selector = next[0][1];
        s.join(next_selector);
    }

    return s;
 }

identifier =
 id:[a-zA-Z_]+
 {
    return id.join("");
 }

integer_selector = 
 value:(integer_range / integer) next:("," integer_selector)* 
 {
    s = new Selector(value);
    if(next.length > 0)
    {
        next_selector = next[0][1];
        s.join(next_selector);
    }

    return s;
 }

integer_range "range"
  = start:integer "-" end:integer { return new Range(start, end); }

integer "integer"
  = digits:([0-9]+) { return Integer(digits); }