I've spent a day having some "quality time" with the Hull Pixelbot scripting language. Which is now called HullOS.
The idea is that the computer in the robot (which can be a lowly Arduino Uno) is entirely responsible for converting the plain text of the program into actions. The behaviour will be rather reminiscent of the early 8 bit computers like the BBC Micro and Sinclair Spectrum, which had built in BASIC. They had tiny processors a bit like the one in the Arduino, but they had a lot more RAM than I've got. However, I've just about managed it. A typical program will look a bit like this:
do if %dist<10 yellow move -10 else green endif forever
This HullOS program would make a "cowardly robot". The program repeatedly reads the distance sensor. If the robot is less than 10 cm from something it turns the pixel yellow and moves backwards. Otherwise it turns the pixel green.
There are a few things to sort out, but I'm rather pleased with how it is going. And I've still got around 500 bytes of memory left....