Introduction to Ada: a project-based exploration with rosettas

I would love to get a list of language features that are "free to use with GNAT" and those that are "AdaCore license required." The last time I did Ada (admittedly, back in the 90s) it wasn't all that clear what language features I could use for free. And since we're on lists of things, a list of zero-cost abstractions and non-zero-cost abstractions would be nice.

I'm pretty sure these aren't big issues these days, but there's still a lot of people walking around thinking "I can't use Ada on this project, I don't have budget for a commercial compiler." Maybe a "project manager's introduction to Ada." I would write it myself, but I've forgotten most everything I learned about the language and it's development community.

[Apart from that... young engineers should definitely check out Ada, even if you don't eventually use it. Why it was considered a good idea to create a new language, the problems language designers were trying to solve and how developers used the language to build code that was more bullet-proof than C++ is kind of an interesting story.]

> I would love to get a list of language features that are "free to use with GNAT" and those that are "AdaCore license required."

All Ada language features are present in the free/open source version of the compiler. The proprietary version of GNAT is just updated more frequently I think and has commercial support - they periodically copy their changes into the main GCC source tree.

They have proprietary tools for some kinds of static analysis, but those wouldn’t be considered language features. GNATprove (the theorem prover tool for verifying SPARK programs) is open source.

The last time I bought a license for AdaCore it was to get the unit testing, static analysis and dynamic analysis tools IIRC but, that was about 8-9 years ago. We also paid for training from AdaCore and their main guy came out.

How would you rate that experience?