As Lazlo posted elsewhere, an early version of Grasshopper installs with the latest WIP version of Rhino for Mac.
here: http://discourse.mcneel.com/t/rhino-for-mac-work-in-progress-rhinowip/28040
Install that and then type ExplicitHistory in the Command Line. this will, among other things, launch the Grasshopper Window.
Again, it's a work in progress, but a great step forward.
Think Like a Spec Writer
AC4.55 through 27 / USA AC27-6000 USA
Rhino 8 Mac
MacOS 14.6.1