I do not advocate changing that, but these legacy *TeX variants have their own builtin sets of supported fonts with their implicit style and use them with the normal letters, just like what is done in HTML when you apply an italic style. Has these *TeX variants exist this way they don't need these additions that will be needed only on newer *TeX variants that will not use explicit font variants in their encoding, but directly new distinguished code points (without explicit font style tagging).
There are now many *TeX variants each one having its own local assumptions about the default styles (and layouts) they will apply. If you want to convert any one of them to HTML (or similar rich-text format), you always need to know how these *TeX variants have been "profiled": you cannot simply use the same conversion rules for all *TeX. Now, if new upright maths characters are added, this will just add new complications in the rules used by these converters, with little benefit. The benefit will be visible only when converting to plain-text only (but such conversion is already defective in many aspects, as the maths layout is not representable directly without adding additional notations such as parentheses or some "\"-escaped notations: such conversion to plain-text is in fact, most often, keeping the original *TeX syntax/notation if they want to "preserve" the original semantics) 2016-05-16 10:05 GMT+02:00 Hans Åberg <[email protected]>: > > > On 16 May 2016, at 03:30, Philippe Verdy <[email protected]> wrote: > > > > isn't it specified in TeX using a font selection package instead of the > default one? Also the only upright letters I saw was for inserting normal > text (not mathematical symbols) or comments/descriptions, or when using the > standardized "monospace", or "serif" font (which are not italic by default). > > Most use a macro package like ConTeXt, which is more recent and modern > than LaTeX, and it is not difficult to change so that the Basic Latin > produces math upright style. But legacy is that it is used for math italic, > and it is hard to change that legacy. > > >
