What's the intent for ":"?

I think everyone would agree that ":" is ambiguous. It's one of the few
cases where the braille Nemeth code (but not UEB) cares about the meaning.

Here's a case I came across:  3:30

It certainly could be a ratio. Or it could be a time. In normal use, there
might be more context to help (3:30 = 1:10 or 3:30pm). However, when
standing alone, there is no way to know.

I think both ratio and time are common enough to be in core. Probably also
function definition (f: x → y) is in core along with "such that" ({x: x>0}).

As per the discussion today (and times in the past), the intent should be
on ":" when possible. However, ":" is a case where it doesn't work out
well. One can force the speech (e.g., "intent='to' for ratio or intent=' '
for time). But how does the braille know that 'to' means it is a ratio and
should output the braille for ratios instead of the braille for a
punctuation ":"?

Aside: listening to Khan Academy, "to" is used in something like "3:2" but
"for" or "for every" is used in the videos when there are quantities/units
given as in "3 dogs : 2 cats". So here you would use intent="for" -- so
saying AT should know that "to" used on ":" means ratio is not going to
work.

I think this is a case where pushing intent to the operator doesn't work
despite it being an infix operator and it needs to be on the mrow. Being in
core, an intent value of "ratio" could be spoken as "to" by AT, but still
recognized easily when generating braille.

Thoughts?

    Neil