At the last style review
we were asked to come up with a taxonomy
of "representable entities". Here’s my response:
The "representable
entities" include NaNs, so by
double negation anything not NaN must
be
"a number".
Numbers fall into two
classes: "infinity" and
"not infinity = finite".
Finites fall into two
classes: "zero" and
"nonzero".
I guess nonzero includes
“normal” and “unnormal”
– but I’m not sure if this is as useful as it used to be for just 754
binary numbers.
I don’t want to restrict
unnormal numbers to 754’s
denormal entities because there a denormal had a reserved exponent.
Proposal: zero + nonzero
+ infinite + NaN
= representable entitites.
Warren Ferguson