SEVEN SEGMENT
A readout refuses to invent. Two kinds of state, and the split
is the useful part: a refusal withholds the number, because showing one
would be a lie, and comes back as dashes with the reason stated. A
qualifier shows the number and says what is true about it, because
withholding would also be a lie. The accessible name carries the reason, never
the value being withheld.
318.4
a value it can draw
1.5
the case retro-react gets wrong: it renders 15
-12.5
negative, and the minus costs a cell
99999
more digits than the display has
1e+21
exponent notation, no glyph for e or +
nominal
letters seven segments cannot form
(empty)
no reading has ever arrived
842.1
outside the declared range
318.4
older than its validity window
318.4
reading, but never calibrated
500.0
limited upstream, before the display saw it
318.4
two sources disagree, and picking one is not the display's call
FOURTEEN SEGMENT
The same element with segments="14". Fourteen segments can form
the Latin alphabet, so a string that is unrepresentable on seven is often
drawable here. That makes the refusal a property of the display rather than of
the value, which is the honest way round: the value was never wrong.
NOMINAL
refuses on seven segments, draws on fourteen
PURGE
the alphabet fourteen segments can form
SECTOR 4
a space is a glyph, not a gap
318.4
digits still work
%$#
still refuses what it cannot form