I guess I wasn't really thinking about why choose those names. If it was just that you could have whatever you like - I like (hd x) and (tl x) but that's me.

I guess I wasn't really thinking about why choose those names. If it was just that you could have whatever you like - I like (hd x) and (tl x) but that's me. Or even (0 x) and (1: x) could work. A rose is a rose and all that. What I was really thinking about were things like why have pairs as a primitive and why enshrine the idea of lists as pairs linked up in a certain way? From ac.scm, it looks like the current set of primitives are: (define (ar-type x) (cond ((ar-tagged? x) (vector-ref x 1)) ((pair? x) 'cons) ((symbol? x) 'sym) ((null? x) 'sym) ((procedure? x) 'fn) ((char? x) 'char) ((string? x) 'string) ((integer? x) 'int) ((number? x) 'num) ; unsure about this ((hash-table? x) 'table) ((output-port? x) 'output) ((input-port? x) 'input) ((tcp-listener? x) 'socket) ((exn? x) 'exception) (#t (err "Type: unknown type" x)))) So why that set? Why have chars and strings and symbols? Why have integers and numbers?