type color =
| Named of string
| HSL of {
h : float;
s : float;
l : float;
}
val green : color
val blue : color
val red : color
val purple : color
val hsl : h:float -> s:float -> l:float -> color
type style =
| Filled of color option
| Dotted
| Dash
type shape =
| Ellipse
| Circle
| Diamond
type property =
| Color of color
| Font_color of color
| Style of style
| Label of string list
| Shape of shape
val filled : color -> property
val txt : string -> property
val make : property list -> decoration