> The ordering of the S and SS fonts is immaterial here because > the C/A/T _had_ no SS font. > Nor do I see any of evidence of an "SS" font for _any_ device > in Documenter's Workbench 3.3 troff. > Barring evidence of pre-groff usage, then, I submit that the > slanted symbol font must be a groffism.
No disagreement here. Neither the C/A/T nor the APS 5 had an SS font. But both had a symbol font containing upright Greek capitals and slanted Greek lowercase letters, specifically intended for typesetting mathematical expressions (based on a century of established mathematical typesetting conventions[*]). The SS is a groffism introduced to replicate this behavior in a compatible manner without having a symbol font with the above properties, in such a way that eqn could simply request \(*A or \(*a and troff would automatically provide the correct character. [*](I'm wondering whether these conventions might not have had much older roots, namely in the fonts (Garamond, Didot, Porson) historically used to typeset some of the Greek classics, which similarly had "roman" uppercase and "italic" lowercase Greek letters.) > > and nothing needs to be changed. > I disagree, because nroff output is incorrect, failing to render > lowercase Greek letters in italics when troff output _does_. I see. Since groff does not provide a usable neqn, I had never considered using groff for typesetting math for the terminal. (But see below.) > sin ( 2 theta ) ~ = ~ 2 ~ sin theta cos theta > (Note to self: an eqn full space should render as a space on > nroff devices. File a bug.) No bug, simply "set thick_space 100" in eqnrc for the terminal devices. In addition to this, I'd suggest not to habitually try to override the default spacing rules of eqn, sin ( 2 theta ) = 2 sin theta cos theta since eqn already inserts thick_space around relations. > Further, nothing in eqn documents its sensitivity to the font > mounting order when determining the typefaces to be used. > In fact that sensitivity overrides explicit configuration! I'd assume this is a good (= flexible) thing. Eqn requests character "\(*h" (= theta), and troff provides this, from whatever font the user has supplied that contains this character. > .\" "letter" means "slanted" in GNU eqn > .\" This is actually redundant with the default configuration. .EQ chartype letter \(*h sin ( 2 theta ) = 2 sin theta cos theta .EN \(*h Interestingly enough, the "chartype letter \(*h" is already sufficient to switch the thetas from eqn into italic (or rather, underlined) on my terminal, while the \(*h from the last line remains normal, i.e., this simple change already achieves what your proposed modification is meant to do. (?) (I assume this is because on the utf8 device, the theta is provided by a normal text font, whereas in the postscript device it comes from the special font.) > > 1-4: R, I, B, BI (standard text fonts) > > 5: CW (computer/monospaced) > > 6-9: SS, S, ZD, ZDR (special) > Heavens no! "CW" is a System-V-ism. We have CR, CI, CB, and CBI. Yes, but it explains why there are 5 empty positions in the "fonts" declaration before SS, S, ZD, and ZDR. :-)
