Fearless extensibility: Extending THINK Pascal

I was thinking about the theme yesterday, and one of the idea I’d like to showcase is the fearless software extendability of the Macintosh, or how you can modify a closed-source program, from the outside, without recompilation, in a standard way across an entire OS. I’m using here everyone’s favourite most badass IDE THINK Pascal(swoons), and I can add/remove items in the menu bar, rename their labels, change the shortcuts, all without opening the program itself or recompiling it via ResEdit. I...