i should have realized this even before noticing ecl's limitation for logs of ratios, but at least i finally did....

since i'monly using log to find the exponent for an arbitrary precision replacement for format's ~e, it works to truncate first. so i ended up with this: (defun ilog (n &optional (base nil base-p)) "return floor of base b log of n" (let ((s (if (< n 1) -1 1)) (trunc-n (truncate (if (< n 1) (/ n) n)))) (floor (* s (if base-p (log trunc-n base) (log trunc-n)))))) One could use let* and then test s when choosing between n and (/ n), but i choose instead to let the compiler optimize the two calls to (< n 1). that makes my ~e replacement work exactly as desired on all lisps i've tried. (I have a ~// function which chooses output baed on the arg's type, with ratios done via that print-e-significant-digits function and everything else using write.) -JimC -- James Cloos <cl...@jhcloos.com> OpenPGP: 0x997A9F17ED7DAEA6