Saved you a click and a referral:

As of yesterday, Microsoft has released the version 1.1 source code of “Microsoft BASIC for 6502 Microprocessor” on GitHub

It’s Microsoft BASIC btw.

Another situation where many people will be surprised to find out it wasn’t already open source. It’s kinda comical to imagine them caring to keep that source code a secret decades after its deprecation.

Chooses to use picture of machine that ran Commodore Basic as illustration

That's what I learned on!

First purchased*

and then everyone clapped

*slow clap*

Years ago I started out programming in QBASIC specifically because ms-dos came with a flavor that had a number of games that you could run. With the gorillas game (two gorillas throwing exploding bananas at each other) I had a direct feedback loop on what the code changes did. No book or help files, just raw edit and trial-and-error. Later on I moved to DarkBasic which was essentially a basic wrapper onto a 3D engine for making games. I loved both for their simplicity.

What would be the similar modern corollaries if I wanted my kids to have that early exposure nowadays?