• Lisp is responsible for most of the parts of programming widely considered enjoyable.

• Fortran is still often used in some of our most performant libraries.

• POSIX shell was one of the most important parts of unix-like systems becoming how they are today, and it’s compatibility is still an invaluable glue for tying programs written in the 90’s to programs written today.

when it comes to banging shit out, when you need more juice than bash, perl was capable of some crazy shit. I found it really frustrating trying to learn real programming because I was taught perl extremely thoroughly and for most other languages programming exercises you have to get 3/4ths of the way through the book before you’re beyomd what perl can do in a couple of lines.

I eventually learned proper oo programming and compiler languages but there were a few years in the late 90’s and the CGI-BIN days where a solid grasp of perl made you feel like a real hacker-ma’am.

As an example I give you the ‘flip flop operator’, (no idea if perl was the first language to incorporate this, but i saw it there first) which would allow you to parse any data stream, and execute a code block on every line in the data stream between two matching regexes. Absolutely invaluable for screen scraping and would let you hit a URL and extract just the data you needed with about 4 lines of code total, including the library call for the get!

Well, pre-2000 is quite a strong limitation here. In the last 25 years in programming, basically everything changed. It’s hard to find anything older than 25 years that’s even still relevant.

But I would say Lisp, or what it brings, mainly the ability to do meta-programming, using code to change/generate code. It basically solves what AI is being used now to solve, namely generating boilerplate code. In many languages, there is just so much shit you have to write to get to the actual creating a solution, problem solving part, which you can very cleanly circumvent with meta-programming, greatly reducing the mental load necessary to understand programs if used correctly. But, like many things, it’s hard to use, easily misused, and thus requires you to be very smart about it. Many programming features and conventions and so on attempt to basically safeguard you from incompetent programmers, or rather allowing you to work with incompetent programmers without them being a detriment more than a benefit. Needing to decipher arcane macros is quite challenging indeed.

There are a couple of Lisps newer than 2000, like Clojure, which I would have mentioned without your limit, and which I’m now circumventing by talking about what the limit prevents me to do.