It depends on what you want. If I wrote aerospace code I'd probably buy adacore's ada and spark compilers and tools.
Since I mostly do scripting work, I usually stick to Python, Bash, & Powershell though.
Some commercial compilers are very affordable with extremely sane licenses. One that has interested me lately is called 8th and is $250 for a professional license which lasts forever and can create encrypted binary executables on Linux, Mac, Windows, raspberry pi, iPhone, android, or embedded all with a cross-compiler, builtin graphics, sound, database support, full REPL, good support...etc. There is also a free version that just has some features missing (not a dumb temporary trial) and a $50 hobby license with many of the features. The Enterprise license would be expensive for me, but fairly cheap for most companies and includes priority support and the source code, so that is neat. I'm all for open-source, but if we're honest, some commercial tools are great and don't abuse users. It is not an only option situation.
I will say closed source can really stink too. I once had to use a product that all of the vendor's customers had to use, but it wasn't officially supported (although it was critical for infrastructure) and I was running into a bug they couldn't figure out or didn't care to look into. The terminal would tell me the problem was in line x of the encrypted script, but wouldn't let me know what line x did so I could get the app working.
Yea it's this one. The main developer wrote an open source Forth called Reva-Forth awhile back. I think he does a lot of paid development a across various fields from phone app development to embedded work, and machine learning stuff. When he was trying to do phone apps he realized (like most of us) that it is a pain to need to know Java for Android (+ API) and Objective C or Swift for iOS and then there is WinForms or Gtk or WxWidjets for desktop development, so you have to learn a lot of different technologies if you want to write software to run on all major platforms and 8th helps solve most of that problem. 8th is also a Forth, but he has added some features like using JSON as a generic data structure (not generally done in Forth), bundled the C++ JUCE GUI framework and associated licenses, added ODBC/SQLITE/MYSQL support, sound, cross-compilation to many platforms...etc.
Most of my coding needs fall into either general scripting (Python, Powershell, Bash, Perl...etc) or numerical work (Python + Numpy or Julia). 8th seems to be pretty speedy, but Forths in general usually aren't lightning fast due to their stack usage and emphasis and you need really fast code for numeric work. He has made it a priority to work on performance though and continuously adds scientific features like adjacency graphs, so he is on the right track and I'll keep my eyes on it. For general scripting work and utility apps it should work pretty nicely for my needs and distributing a tiny .exe to users with a GUI is nice. I'm not sure how good the file I/O & filesystem support is though (need to look at the doc), because I use those common features a lot. I also need to check if he wrote functions (called words in Forth speech) for web scraping as there is a project I'd like to do where 8th would be ideal.
If you've never seen Forth before, try to keep an open mind with the syntax as it can look alien at first. There are a lot of 8th examples on Rosetta Code and although they are short, it might look like gobblygook if you're not used to thinking about the stack where parameters are popped off and used in functions which then return data to the stack so functions can be chained (kind of like Unix pipes). Leo Brodie's books on Forth (classics and free online) are called "Learning Forth" and "Thinking Forth" and are recommended on HN sometimes.
I did try out Forth a little, much earlier, and had read some of the Starting Forth book - had bought the hardcover edition, it looked really good, including the cover - dark brown, either was leather or had a leather effect (more likely the latter). And I liked Leo's writing.
Will check out 8th at some time. The cross-platform GUI thing with tiny EXE's is a pro (Rebol and Red are similar, except not sure if Rebol supported EXEs, except maybe via 3rd-party tools), although not having good I/O and filesystem support is a con, since a lot of the stuff I do involves file I/O.
I was going to mention that it is a lot like Rebol and Red in philosophy, but you beat me to it.
Rebol was mostly built by one person (Carl Sassenrath) but has to package the entire interpreter (I think maybe 5 MB) to make an .exe if you have the paid version. Red can already make executables and has made fantastic progress, but it is a larger effort. I check up on Red once a month and think 1.0 will be amazing.
The page seems to spend all it's effort promoting how the language is cross-platform. Given the number of cross-platform languages nowadays, I wouldn't think that would be a good selling point (more of a check box).
They do seem to do that a good bit, but is there really a one stop language you can code in from a high level with REPL that can run on several desktop operating systems AND android/iPhone AND em embedded? I'm not aware of any, but that isn't really my area of use. C obviously can, but C is pretty low level and not a super productive language for most. So when they say cross-platform they mean write once and test on your laptop and then cross-compile to all those supported platforms. That is different than Java's write once and run on 3 out of the 6 platforms I mentioned with the bulk (and power I suppose) of the JVM. Note that I'm not saying this or similar philosophical languages like Rebol/Red are the answer to everything as they most certainly are not. If I'm writing something that has to scale to millions of users (something I know next to nothing about), I would likely use Java or Erlang. These languages (8th, Red, Rebol) are really good at allowing you to build reasonably performant applications in a super easy and interactive manner and satisfy a definite need that isn't satisfied by most common enterprise languages. Python is easy to script in, but doing GUI work or trying to deploy is painful. Java requires a nearly painful amount of boilerplate.
> "Programs that manipulate other programs are powerful, interesting and fun. I’ll use Ruby to take you on a tour of how interpreters and compilers work, introduce the ideas behind a technique called partial evaluation, and explain a surprising computer science result which allows compilers to be generated automatically."
As usual, the only relevant post is downvoted to submission. Can you all stop downvoting honest and helpful comments? This is one of the most hostile communities on the internet today. The post title is 100% misleading, it is not a large list of Compilers that are free. Which is what I expected. It's all about Ruby... Why was Ruby not in the title? OP should fix the title.
https://ecee.colorado.edu/ecen5533/fall11/reading/free.pdf