Lisp as the Maxwell Equations of Software (2012)

I admit that I don't completely understand Lisp's claim to fame. Yes, programs in the language are represented by a built-in data type, and you can write a self-interpreter quite easily. But the same is true for a simple assembly language, if you know the instruction encoding! You can represent a program as a code pointer, and it's easy to write an analog of "eval" by hand, using just a handful of arithmetic instructions and conditional jumps. What's more, such…

I discovered you can get eval to recognize natural numbers without introducing more primitives if you take the number in binary, enter it into a list, reverse it, and replace the 1's with t's and the 0's with nil's. If you do it that way, you can binary right shift a number by consing a nil at the front, or binary left shift by taking the cdr. You can increment, decrement, add and subtract efficiently, too. Even take logarithms. I…

I thought the same thing for a long time, I found s-expressions very elegant. Then I discovered lambda-calculus, with its scary syntax but based on a process I could understand, text-rewriting. So I had the idea to explore the lambda-calculus using s-expressions and patiently rebuilt booleans, pairs, lists, recursion and beyond a real complete Turing language, for instance: - http://lambdaway.free.fr/lambdawalks - http://lambdaway.free.fr/lambdawalks/?view=lambdacode5 No need for cons, car, cdr and other…

I've said this before, but I've come to think of Lisp and Forth as the left-handed scissors of software: for 10% of the population they're significantly easier to use, to such an extent that it can feel like a revelation. The remaining 90% of the population tries it, finds it harder to use, and doesn't get why others are raving about it. This would be down to very fundamental differences in thinking and conceptualisation that are difficult or impossible to…