MacNQC
MacNQC is a stand-alone version of the Not Quite C (NQC) compiler for the Macintosh OS 9/10 PowerPC architectures. Not Quite C is a simple language with a C-like syntax that can be used to program the LEGO RCX programmable brick (from the Mindstorms set).
Origin
MacNQC was originally written by David Baum and later maintained by K. Robert Bate. The last update was in 2004.
Features
The main window of the program is an editor for the NQC language. The editor color-codes the syntax of the language. Multiple files can be edited at the same time. From the editor you can call the compiler and download the code to the robot. There are many other functions, like windows to watch what is going on in the robot, to control the robot directly, to control the robot with a joystick, diagnostics, to let the RCX make music, and tools for downloading firmware, etc. Online documentation is also available for both MacNQC and the NQC language.