I'm not sure what the IDE for Grasshopper is but since Rhino is in process of being 'ported' to OS X is there any chance of Grasshopper becoming available on OS X? Reading between the lines maybe it's developed in C# ?
Can't help mentioning Quartz Composer (a Visual Programming application bought by Apple and then developed extensively since as part of Developer Tool suite for developing run-time compiled image processing compositions). Comparing QC and Grasshopper is really interesting in terms of handling data structures/ spreads/ arrays and generally how differently the visual interfaces are despite the obvious genre similarities. QC can handle some basic (OpenGL) 3D primitives and has started on meshes with OpenCL support but is as they say a work in progress with regards to working with meshes and OpenCL in general.