It's a trade-off. Using code font gives the thing a uniform look, and we do actually define the meaning of the notation. So it's not outright wrong. It's similar to how we use code font for conceptual placeholders, e.g. T when referring to an invented type. Not all code is code, if that makes sense.

It does make sense, it's just a bit unfortunate for cxxdraft-htmlgen that the same commands/environments are used for C++ code and non-C++ code, because cxxdraft-htmlgen should only syntax-highlight C++ code as C++. I currently use a patch that introduces \noncxxtcode and changes \Range to

\newcommand{\Range}[4]{\noncxxtcode{#1}\tcode{#3,\penalty2000{} #4}\noncxxtcode{#2}}

but it's not ideal. :)

It's a trade-off. Using code font gives the thing a uniform look, and we do actually define the meaning of the notation. So it's not outright wrong. It's similar to how we use code font for conceptual placeholders, e.g. T when referring to an invented type. Not all code is code, if that makes sense.

An important difference is T can be well-formed and well-defined C++ code when in some invented context with intended meaning, but the interval notation is hardly in this sort.

Interestingly, there's a bunch of places in numerics.tex that don't use the range macros but instead use

$\bigl[ ... , ... \bigr)$

Example

Probably an oversight, but I'm reluctant to submit a patch to replace these with uses of the range macros, because I love the math brackets more than I hate the inconsistency. ;)

Editorial meeting: Do move away from \tcode for brackets and comma. Try the looks of two center dots as separator, with math brackets. Do not proceed without @tkoeppe's input.

Cool, thanks for the decision! I'd be happy to submit a patch to move away from \tcode for brackets and comma.

The idea of using two center dots as separator surprises me a little bit though, because combining center dots with round and square brackets to indicate inclusive-ness of the bounds doesn't match conventional mathematical interval notation. What would be the motivation for changing from comma to two center dots? :)