Re: [sc-dev] Proposal of a new format character from engineer's/scientist's prospective



On Thu, 2004-01-22 at 16:00, Jody Goldberg wrote:
Hmm, I'm not at all sure that is a good way to go.  Ignoring how we
would express arbitrary scaling that leads us towards
    [>1000]0 km;[>1]0 m;[>.01]0 cm; ....
Which is seems untenably complex to me.  Even the other proposal of
    si:k-cm
seemed prone to error.  Our goals seem to be
    a) select from a hard coded set of prefix/scale factors
    b) provide a unitstring with no semantic knowledge of what that
       unit is.
    b) provide a min/max useful unit prefix
    c) avoid using a less common prefix sometimes (dm)

b) and c) don't go very well together.  deci is only commonly used with
liter, and never with watt, ohm or pascal.  actually I think it's only
meter and liter which see any use of the non-thousand units.  I'm not
sure it's worthwhile to support it, you could possibly hardcode an
exception for the unit "m".

[%scale_factor_set;max_prefix;min_prefix;comma seperated list of exclusions]
So your example would be
    [%si;k;m;d]

I'd prefer min;max;inclusions, ie., use thousands based units by
default, with no way of saying "G and k, but not M".  the inclusions can
be used for listing deca, deci, centi when the user needs them.

The main limitation here would be localization.  Are there any
translations that use different names for 'si' or its associated
prefixes ?  This is more general than my generic 'use si' approach,
but less powerful than your pre-prefix selection.

the English translation of SI is IS.  you don't see that used much, do
you?  :-)

NIST has generally been credited with the binary prefixes, but you could
call it SIbi instead ;-)

-- 
Kjetil T.





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