This was incredibly helpful and alleviated the anxieties I get from all these Top n Programming Languages You Should Learn NAOW!!! which always seem to magically note that the language you're currently sweating over for hours upon hours is dying. That said, I was given advice some time ago to learn the language(s) that have influenced your choice (or your employer's choice).
I don't know how true or useful it is as a general rule but I have found clarity in playing with Smalltalk (recently) and Lisp, reading about the ideas that each bring and having it clarifying principles, idioms in Ruby. An example is that I've always found OOP just out of my grasp of full understanding. Borrowing a book by Sandi Metz and just working through some trivial examples in Smalltalk, reading where some of these OO conventions came from has helped - a lot.
However this still may fall into your Study Design Principles more than advocating for learning a new language. (I don't pretend to be an expert in either of those languages whatsoever).
I hear you, Luis. I've been programming in PHP for more than 15 years and people have been dumping on that language and predicting its demise the whole time. But it's still here and at my work we have no plans to switch away from it.
Uncle Bob's got a nice essay on his observations the correlation between programming language evolution and processor speeds: blog.cleancoder.com/uncle-bob/2017...
I believe people are going to be maintaining C, C++ Cobol, Java, etc., etc., for the foreseeable future. If you are a good programmer and know a language with a huge number of lines in production, you'll probably always be able to find work.
So carry on and don't worry about learning the newest language (unless you want to learn it, of course).
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