Very clean and easy to read, thanks for sharing. That code is amazingly illuminating.

Thank you!

I'm reading it and I'm just wondering what this line means

    (eqv? #\1 (call-with-input-file userns-file read-char))

specifically the #\1?

#\ is the weird syntax for character objects in Guile, so #\1 is the character "1". This expression reads a single character from userns-file and checks if it is the character "1".

what language is written in? It looks like lisp, but exceptionally readable.

Scheme, Guile in particular: https://gnu.org/s/guile

Scheme, according to the file extension, .scm