@Carl Love

First, you see that basically all the other non-alphanumeric characters already have a syntactical meaning. Of course, each one could be seen *"ad hoc*" and indeed mathematical notation gives meaning in "*ad hoc*" ways, e.g. *A!* means the factorial of *A*. In fact, the prime non-alphanumeric character, ', also has "*ad hoc"* meaning: the input *x'* is syntactically correct and interpreted as differentiation with respect to x. But then, in rather frequent mathematical notation the input *x'* is also used with a different meaning, to denote a variable that in some context (e.g. transformation of coordinates, or Green functions) we think of it as somehow related to *x*.

Now, if *x'* is accepted as syntactically correct to mean differentiation with respect to *x*, if **Typesetting:-Settings(':-useprime' = false)** it is natural to me that the same input *x'* is still syntactically correct just not meaning differentiation, and that is all I implemented now. Is this *natural*? If you read the original post by @nmacsai you see that is what appeared natural to him too, he asks:

- "
*Can I disable maple's use of the ' function? (aka prime/derivative function) [..] Is there a way that I can disable the operator function of ' so I can use it as a naming scheme*"

The answer now is: yes you can disable the prime/derivative function in order to use the prime as a naming scheme. and "without changing anything" since the syntax *x'* was already allowed as input. All we have now is that, naturally, after disabling prime differentiation you can use *x'* as a variable.

But even if @nmacsai had not asked about this, consider the input shown:

It is my opinion that, once I set in my mind that *t'* does not mean *differentiation with respect to x*, the natural way to input this is **psi(t) = Int(G(t, t') * psi(t'), t)**, not having to input **`t'`** which for me only indicates there is some obscure computer reason for something so absurd (from the point of view of a human) as having to surround with ``. So all you need is a mimicry of "set in my mind that *t'* does not mean differentiation with respect to *x*"*,* and that mimicry is achieved entering **Typesetting:-Settings(':-useprime' = false)**.

As another example, in a recent post I made here in Mapleprimes about Einstein's principle of relativity, there is one place where - when writing the post - I felt rather uncomfortable; copying from the post:

I felt horrible. The motivation for this line was the same as the motivation of @nmacsai to write the question we are replying to here. In physics, **you very frequently use the ' to denote variables**. That day it didn't pass through my mind that I could fix this in a natural way: tell the system that ' does not mean differentiation and fix the inconsistency that *x'* is valid syntax (when it is differentiation) and, at the same time, not valid syntax (when it is not differentiation). Now it is always valid syntax. And that addresses the other frequent use of the prime ' in mathematical notation, which is to denote variables.

All that said, I am not trying to convince you or anyone, maybe we just see this differently, and if you prefer to input surrounding with ``, as in *`x'`* instead of *x'*, and both with the same meaning (*`**x`* and *x* also have the same meaning), well, you can still do it. By the way, none of this represents the maintenance problem you suggest.

Edgardo S. Cheb-Terrab

Physics, Differential Equations and Mathematial Functions, Maplesoft