[michaeltiller]

JuliaSim does have graphical representation, a GUI and an IDE. But, granted, it is also a commercial product, not open source.

[wolvesechoes]

But this representation is exclusive to JuliaSim, is it not? MTK package didn't have equivalents of Dialog, Icon and Diagram annotations the last time I checked.

[michaeltiller]

It is exclusive to JuliaSim. But the tools generate MTK compatible component models so, once built, they can be used with MTK.