Why don't you go look up Linux, that way I don't have to list tens of thousands of applications, including dozens of language implementations. If you want someone to learn software development, or computing in general, Linux is a far better starting point than Windows or OS X.
Yeah, yeah. Lots of open-source half-baked projects with no support and incomplete features. Advertised as "photoshop replacement" or "complete IDE" but turns out, missing critical features, crash right and left, won't work on modern hardware etc etc.
Been down that road, burned more times than I can count. I wish it were true, but I don't fool myself into believing it.
You do realize that with the exception of one or two of the IDEs, the "mac dev tools" run or originated on Linux or other similarly now free systems, right?
Linux costs 0, and runs on far less capable devices than the RaspberryPi.