RE: bike shifting - output decimal in percent

[Drew Adams]

> the original program is _much_ better:
> 
> ;; test - should be 43% for
> ;; (bike-compute-step 42 24) ; "43%"
> 
> ;; (percent-string 0.01)  ; "1%"
> ;; (percent-string 0.1)   ; "10%"
> ;; (percent-string 1)     ; "100%
> ;; (percent-string 2)     ; "200%"
> 
> ;; (format "%2.2g%%" (* 100.0 0.01)) ; " 1%"    (?)
> ;; (format "%2.2g%%" (* 100.0 0.1))  ; "10%"
> ;; (format "%2.2g%%" (* 100.0 1))    ; "1e+02%" (!?)
> ;; (format "%2.2g%%" (* 100.0 2))    ; "2e+02%" (...)

It all depends on what you want and what your expected
input is.

(format "%1.1d%%" (* 100.0 0.01)) ; "1%"
(format "%1.1d%%" (* 100.0 0.1))  ; "10%"
(format "%1.1d%%" (* 100.0 1))    ; "100%"
(format "%1.1d%%" (* 100.0 2))    ; "200%"
(format "%1.1d%%" (round (* 100.0 0.42857142857142855))) ; "43%"

(defun percent-string (decimal)
  (format "%2.1d%%" (round (* 100.0 decimal))))

Like I said (regarding CL `format', but the same is true
of Emacs-Lisp `format': it's a language unto itself.