# Typing units correctly

**Tom Pledger
**
Tom.Pledger@peace.com

*Tue, 13 Feb 2001 09:59:37 +1300*

Dylan Thurston writes:
| Any such system would probably not be able to type (^), since the
| output type depends on the exponent. I think that is acceptable.
In other words, the first argument to (^) would have to be
dimensionless? I agree. So would the arguments to trig functions,
etc.
Ashley Yakeley writes:
| Very occasionally non-integer or 'fractal' exponents of dimensions
| are useful. For instance, geographic coastlines can be measured in
| km ^ n, where 1 <= n < 2. This doesn't stop the CIA world factbook
| listing all coastline lengths in straight kilometres, however.
David Barton writes:
| Even without fractals, there are cases where weird dimensions come
| up (I ran across this in my old MHDL (microwave) days). Square
| root volts is the example that was constantly thrown in my face.
In both of those cases, the apparent non-integer dimension is
accompanied by a particular unit (km, V). So, could they equally well
be handled by stripping away the units and exponentiating a
dimensionless number? For example:
(x / 1V) ^ y
Regards,
Tom