Technologies like Entity Framework and Asp.net MVC have been open source for some time now, so although the open sourcing of the .net compiler wasn't a complete shock, it has opened up a world of new possibilities. The first thought that probably popped into people's heads was running web sites and services on cheap Linux boxes, and that is right around the corner, but what I figured I'd take a look at is developing and debugging .net applications on my Mac.
The first thing you will want to check out is Visual Studio Code:
Right now I'd consider this a text editor with some pretty impressive IDE capabilities. For c# and TypeScript, you can do things like find all references to a symbol, refactor symbol names, either go to or peek definitions. Plus it's got full Intellisense for supported languages. The first thing I did after downloading it was compare it to Sublime Text. Since VS Code doesn't support plugins, I wanted to see if it could do everthing that my Sublime with plugins could, and surprisingly, it did! I have a diff plugin for ST that is matched by VS Code's "Compare Active File With" functionality - which displays side by side diffs for any two files. I also needed something that made unformated JSON and XML look pretty. For Sublime I used a package called 'Indent XML', and this is totally outclassed by Visual Studio Code's "Format Code" option! VS Code also supplies both automatic bracket highlighting as well as one-button Markdown previewing - again both things I needed packages for in Sublime Text.
As you can see I'm using Mono to run the actual .net code on the desktop in OS X. You'll have to jump through a few simple hoops to get this all up and running and it is outlined here.