parser generator

[choltreppe]

You could write it like that:
    
    
    import std/[strutils, strformat]
    import /home/joel/daten/programming/nim/parlexgen/src/parlexgen
    
    type
      TokenKind = enum tkRect, tkSep, tkNum
      Token = object
        case kind: TokenKind
        of tkNum: val: float
        else: discard
      
      Rect = object
        x1, y1, x2, y2: float
    
    makeLexer lex[Token]:
      "Rect": Token(kind: tkRect)
      r";|,": Token(kind: tkSep)
      r"[0-9]+(.[0-9]+)": Token(kind: tkNum, val: parseFloat(match))
      
      r"[ \n\r]+": discard
    
    makeParser parse[Token]:
      rect[Rect]:
        if (tkRect, tkNum, tkSep, tkNum, tkSep, tkNum, tkSep, tkNum):
          Rect(x1: s2.val, y1: s4.val, x2: s6.val, y2: s8.val)
    
    func `$`(rect: Rect): string =
      fmt"Rect {rect.x1} {rect.y1} {rect.x2} {rect.y2}"
    
    echo $parse(lex("Rect 10.0    ;20.0,100  ,  200"))
    
    
    Run

but its not realy made for simple cases like that. Its made primarly for 
complex recursive things like starting from math expression up to programming 
languages