measurement-to-length

Description

Given a string containing a measurement, return that measurement as a length.

Example

"2.5cm" returns 2.5cm as a length. "3.4barleycorn" returns 6.8pi.

Author

Norman Walsh, <ndw@nwalsh.com>

Source Code

(define (measurement-to-length measure)
  ;; Convert a measurement to a length
  (let* ((pm (car (parse-measurement measure)))
	 (pu (car (cdr (parse-measurement measure))))
	 (magnitude (if pm pm "1"))
	 (units     (if pu pu (if pm "pt" "default")))
	 (unitconv  (assoc units unit-conversion-alist))
	 (factor    (if unitconv (car (cdr unitconv)) 1pt)))
    (* (string->number magnitude) factor)))