/+dub.sdl:
dependency "pegged" version="~>0.4.4"
+/
import std.stdio;
import pegged.grammar;

mixin(grammar(`
Graph:
              Node < Entrance / Connection
              Entrance < "E" identifier Type
              Type < identifier
              Connection < identifier (RedEnding / BlueEnding)

              RedEnding < "R" identifier
              BlueEnding < "B" identifier
`));


// entrances declare a functio n to call
void main()
{
    // "blue entrance" is a value

    enum parseTree1 = Graph(`
    E fun
    a B b
    b R c
    `);
    //
    auto box = asBlackBox(parseTree1);
    box.fun =
                            // pink functions are called
    // blue ending and pink ending
    // pink ending triggers calls
    // blue
    // blue -> blue collapses to blue (lazy function)
    // blue -> pink triggers pink when blue changes
    // pink -> blue sets a value
    // pink -> pink collapses to pink


    writeln("Hello D");
}