Strange error: single character string constants

[freeflow]

Indeed, I continue to explore how nim can be used better. I now have those 
single character string defined as chars and am experimenting with
    
    
    type
        direction = enum
            North = (0,  $twHat)
            East = (1, $twRAngle
            South = (2, "v")
            West = (3, $twLAngle)
    
    
    Run

and I've moved the individual blizzard seq into a Table
    
    
    s.Blizzards=[$North: newSeq[Point](), $East: newSeq[Point], $South; 
newSeq[Point](), $West: newSeq[Point}()}.toTable
    
    
    Run

which is working well, although I couldn't understand why
    
    
    s.Blizzards = {$North; @[], $East:  @[], $South: @[],  $West: @[]}.toTable
    
    
    Run

refused to compile even though s.Blizzards has been assigned the Type of 
Table[string, seq[Point]]