24.4 Foreign Functors: Graphical Output for a Chart

You can also use functors written by others without knowing their precise definition. For instance, let us use a functor for displaying a chart as a window.

<Graphical Output of a Chart>=

declare 
<Functor To Module> 
NewChart = Mod1.newChart
ChartToWindow = Mod2.chartToWindow
 
Phons = [john sees the man 'with' the telescope]
Edges = <Edges> 
Chart={NewChart Phons}
{ForAll Edges Chart.add}
 
Window = {ChartToWindow Chart}