The situation was pretty bad a few years ago, and the licensing was confusing but it's pretty straightforward now with Alire. (AdaCore also got rid of their "Community Edition which had the weird license restrictions).
I'm doing a presentation at FOSDEM next year called "Get started with Ada in 2 minutes or less!"[1]; because (on MacOS and Linux) I can go from not having no toolchain a all to compiling hello world in under 2 minutes (I've timed it).
Here's some steps:
1. open your terminal, run the following command: curl --proto '=https' -sSf https://www.getada.dev/init.sh | sh
Congratulations, you now have Alire!
2. Run the following command: alr init --bin hello
Now you have a fully structured Ada project, gpr files and all!
3. Edit your program in hello/src/hello.adb
You can use vscode to open the hello folder with the Ada Language server, or just run "alr edit" to open your editor with all of the files built in.
4. Compile with: alr build
Alire will automatically grab the latest native toolchain (gnat, gprbuild, etc) and compile the program.
If you want to use another toolchain, such as for cross-compiling, or another version of GNAT, simply run: alr toolchains --select
5. Run the program: hello/bin/helo
On windows, you can just download the windows installer; alire is also on Freshports for the BSDs.
[1] https://fosdem.org/2025/schedule/event/fosdem-2025-5056-get-...
