I use it to run Arc, which I use as my go-to general-purpose programming language. I use it to do math, Project Euler problems (not exactly the same thing), so

I use it to run Arc, which I use as my go-to general-purpose programming language. I use it to do math, Project Euler problems (not exactly the same thing), sometimes to control the computer [I sometimes run programs that click the mouse for me, and used to make it type as well], to generate repetitive code[1] for usually experimental purposes, and occasionally to make complicated projects like a sudoku solver, or a thing that reads and writes WAV files. Racket is pretty good, is pretty fast. It can add the integers from 1 to 100 million in 407 milliseconds on my machine. If you need incredibly speedy numerical code, it is still possible to load machine code, perhaps from a C dynamic library, and run it. My main objection is that it doesn't have real-time garbage collection. We'll see about that. [1] Don't get excited, I haven't written a compiler or a working assembler (yet). I mean things like this: (pbcopy:tostring:on x '(rax rbx rcx rdx rdi rsi rbp rsp r8 r9 r10 r11 r12 r13 r14 r15) (prn " " "mov [rel teh_end + " (* index 8) "], " x)) --> clipboard now contains the following: mov [rel teh_end + 0], rax mov [rel teh_end + 8], rbx mov [rel teh_end + 16], rcx mov [rel teh_end + 24], rdx [...]