Re: pure-fns in byte-opt.el

[Stefan Monnier]

> Why? Its return value clearly only depends on its argument, and it doesn't
> change any global state. It's the poster child of a pure function!

  (let ((s (make-string 5 ?a)))
    (list (string-to-char s)
          (progn
            (aset s 0 ?b)
            (string-to-char s))))

If string-to-char were a pure function, it would return the same value
in both calls (since the arguments are `eq').


        Stefan