bin/50768: units(1) silently fails on negative exponents

[dholland%netbsd.org@localhost]

>Number:         50768
>Category:       bin
>Synopsis:       units(1) silently fails on negative exponents
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Feb 05 03:25:00 +0000 2016
>Originator:     David A. Holland
>Release:        NetBSD 7.99.26 (20160204)
>Organization:
>Environment:
System: n/a
Architecture: n/a
Machine: n/a
>Description:

Observe:

   % units
   531 units, 41 prefixes

   You have: cm^-2
   You want: m^-2
           * 0.01
           / 100

This is completely wrong; the -2 is silently ignored. The same thing
happens with many more subtle cases, e.g.

   You have: 6.23e+8 horsepower ft^-2 degree^-2
   You want: watt m^-2 sr^-1
           * 3.1056629e+10
           / 3.2199245e-11

(the right answer is 1.6416004e+16)

>How-To-Repeat:

>Fix:
beat on the parser