Re: multi-symbol variables

I think I must not be getting your gist in:

> But if there are contexts & defaults applied, you have to make sure
> that x' is *not* treated as a derivative (by whatever means).
>
> The point is that we not only have to provide a way to assert what
> something *is* (or how it should be pronounced), but in the presence
> of defaulting, we essentially have to say what it's *not*.
>

The point of having defaults is precisely so that you know when adding
intent is required to convey some specific meaning that differs from the
default. If software doesn't know what a default is, then it should
generate an intent value.

In case it isn't obvious, defaults should be simple, but not necessarily
trivial. For example, I think saying "msup" defaults to power is too
trivial, but a simple rule like "msup is a power except when the base is an
<mi> and exponent is an <mo> , in which case it is an identifier name."
(feel free to pick holes in this -- it is just meant to be an example
showing that one can add a few special cases to a default to make it more
useful. This doesn't help for derivative, or transpose, or many other
notations, but it does cover x^*, the x^' examples in the math counts
problems, along with it being a power.

    Neil



On Fri, Oct 8, 2021 at 1:56 PM Miller, Bruce R. (Fed) <bruce.miller@nist.gov>
wrote:

> On 10/8/21 3:00 PM, Neil Soiffer wrote:
> > To return to some of the examples. If someone uses a prime, double
> prime, etc, a literal
> > reading "x double prime" doesn't need anything special
>
> Deyan addressed the question of what a "natural" reading of primes may or
> may not be.
>
> I want to emphasize a different point about specialized pronunciation &
> "defaults".
>
> In real life, I've encountered things like "f' = x' + ....",
> where for example f is a function and prime means to take its derivative,
> while x' is a unique variable, presumably some transformation of x.
>
> If we *never* are going to concern ourselves with output other than the
> literal:
>    "eff prime equals ecks prime dot dot dot"
> and leave it to the hearer to figure it out, then there's no issue.
> (but that seems not to be your POV)
>
> If, on the other hand, we are expecting to say something different for
> a derivative (whatever it might be), then the two instances will *have*
> to be distinguished.
> If there were no defaulting, we would simply assert that f' is a
> derivative.
> (but that seems not to be the POV of several folks)
>
> But if there are contexts & defaults applied, you have to make sure
> that x' is *not* treated as a derivative (by whatever means).
>
> The point is that we not only have to provide a way to assert what
> something *is* (or how it should be pronounced), but in the presence
> of defaulting, we essentially have to say what it's *not*.
>
> bruce
> --
> bruce.miller@nist.gov
> http://math.nist.gov/~BMiller/
>
>