Adding a play button

I'm very impressed by the new Lua-based end-user game programming app for the iPad, Codify. Their approach to the need to distinguish between code manipulation and game interaction is to use a simple play button. That's what we expect with macro recorders, of course, though many environments complicate that metaphor. In Scratch, for example, you can still interact with the code while the program is executing, and it can control its own execution state through use of the green flag.

So after a final Cambridge drink with Sam Aaron and David Coyle last night, where Sam pressed me on exactly what kind of execution this language does, I thought I should add my own play button today. Fortunately, it worked as expected pretty much straight away, and created a whole bunch of new layers on the fly.