VMF (Valve Map Format) Hammer save file parser written in Scala using parser combinators.

VMFParser.scala

import scala.util.parsing.combinator.RegexParsers

object Main {
  val testdata = """versioninfo
{
	"editorversion" "400"
	"editorbuild" "5704"
	"mapversion" "3656"
	"formatversion" "100"
	"prefab" "0"
}
visgroups
{
	visgroup
	{
		"name" "Global"
		"visgroupid" "43"
		"color" "215 212 165"
		visgroup
		{
			"name" "Geo"
			"visgroupid" "44"
			"color" "186 211 144"
			visgroup
			{
				"name" "Main"
				"visgroupid" "45"
				"color" "173 82 107"
				visgroup
				{
					"name" "railing"
					"visgroupid" "29"
					"color" "143 204 173"
				}
			}
		}
		visgroup
		{
			"name" "Models"
			"visgroupid" "47"
			"color" "88 249 190"
			visgroup
			{
				"name" "prop_static"
				"visgroupid" "46"
				"color" "103 244 101"
			}
			visgroup
			{
				"name" "prop_physics"
				"visgroupid" "50"
				"color" "195 224 113"
			}
		}
		visgroup
		{
			"name" "Lighting_Effects"
			"visgroupid" "57"
			"color" "230 159 204"
			visgroup
			{
				"name" "sprites"
				"visgroupid" "60"
				"color" "141 146 155"
			}
			visgroup
			{
				"name" "instances"
				"visgroupid" "75"
				"color" "162 123 104"
			}
			visgroup
			{
				"name" "lights_local"
				"visgroupid" "77"
				"color" "112 97 118"
			}
		}
	}
	visgroup
	{
		"name" "DNC"
		"visgroupid" "42"
		"color" "170 227 176"
		visgroup
		{
			"name" "_fixtextures"
			"visgroupid" "37"
			"color" "203 152 201"
		}
		visgroup
		{
			"name" "_oldoutdoorstreetlights"
			"visgroupid" "36"
			"color" "80 97 150"
		}
		visgroup
		{
			"name" "_oldoutdoorbuildinglights"
			"visgroupid" "35"
			"color" "95 220 125"
		}
		visgroup
		{
			"name" "_oldoutdoorlights"
			"visgroupid" "34"
			"color" "82 139 88"
		}
		visgroup
		{
			"name" "ExitGreenLights"
			"visgroupid" "21"
			"color" "43 209 1"
		}
		visgroup
		{
			"name" "_temp"
			"visgroupid" "38"
			"color" "166 159 220"
		}
	}
	visgroup
	{
		"name" "-art_removal"
		"visgroupid" "51"
		"color" "115 112 113"
	}
	visgroup
	{
		"name" "junk"
		"visgroupid" "10"
		"color" "190 215 132"
	}
	visgroup
	{
		"name" "shrubbery"
		"visgroupid" "11"
		"color" "219 184 217"
	}
}
viewsettings
{
	"bSnapToGrid" "1"
	"bShowGrid" "1"
	"bShowLogicalGrid" "0"
	"nGridSpacing" "64"
	"bShow3DGrid" "0"
}"""
  def main(args: Array[String]) {
    println("Testing the parser:")
    println(VMFParser(testdata))
  }
}

case class VMFDocument(cl: Seq[VMFClass])
class VMFProperty
case class VMFClass(n: String, m: Seq[VMFProperty]) extends VMFProperty
class VMFTuple extends VMFProperty
case class VMFTupleGeneric(n: String, m: String) extends VMFTuple

object VMFParser extends RegexParsers {
  import language.postfixOps
  def crlf = """\r?\n""".r //CRLF or LF
  def ows = """[^\S\r\n]*""".r //optional whitespace
  def owscrlf = ows ~ crlf //optional whitespace followed by CRLF
  def cname = """[^\s{]+""".r //at least 1 of anything except whitespace or a {
  def value = """[^\"]*""".r  //anything except a "
  def valuetuple: Parser[VMFTuple] = (ows ~> '"' ~> value <~ '"' <~ ows) ~ ('"' ~> value <~ '"' <~ owscrlf) ^^ {
    case n ~ m => VMFTupleGeneric(n,m)
  }
  def property: Parser[VMFProperty] = (valuetuple | clazz)
  def propertylist: Parser[List[VMFProperty]] = property*
  //def propertylist: Parser[List[VMFProperty]] = log(repsep(valuetuple | clazz,crlf))("property list")
  def clazz: Parser[VMFClass] = (ows ~> cname <~ owscrlf) ~
                                (ows ~> "{" ~> owscrlf ~>
                                propertylist <~
                                ows <~ "}" <~ (owscrlf | "$".r)) ^^ {
    case n ~ m => VMFClass(n,m)
  }
  def document: Parser[VMFDocument] = (clazz*) ^^ {
    case x => VMFDocument(x)
  }
  override def skipWhitespace = false
  
  def apply(input: String): VMFDocument = parseAll(document, input) match {
    case Success(result, _) => result
    case failure: NoSuccess => scala.sys.error(failure.msg)
  }
}