Let smallcaps be element function

[Coekjan]

Description

emph, strong, highlight and some other functions are element functions, so that we can use set/show rules to customize their behavior. This issue suggests smallcaps be element function.

For the past few days, I looked into how we can customize text font of smallcaps. Especially in math equations, the default math font does not support smallcaps feature. For fine-grained adaptation purpose (i.e. just change font of smallcaps, instead of all text font in math environment), I attempted to customize font of smallcaps in math equations using show rules, but I found it impossible since smallcaps is not element function.

Use Case

#show smallcaps: text.with(font: "linux libertine", fill: red)

just like what we can do with strong, emph...

[Coekjan]

If this is a good suggestion, I can help to implement it and send a PR :)

[Coekjan]

I slightly modified crates/typst/src/text/{smallcaps,mod}.rs, and now it can achieve the behavior:

#set align(center)

$ #smallcaps[SmallCaps] $

#show smallcaps: set text(font: "linux libertine", fill: blue)

$ #smallcaps[SmallCaps] $

#show math.equation: it => {
  show smallcaps: set text(font: "linux libertine", fill: red)
  it
}

$ #smallcaps[SmallCaps inside Math Equation] $

#smallcaps[SmallCaps outside Math Equation]

[Coekjan]

The reason why smallcaps in math behaves differently seems relative to #366

[Enivex]

The reason why smallcaps in math behaves differently seems relative to #366

It is. Math fonts rarely (never?) have small caps, because they're not intended for use as a text font.

[Coekjan]

It is. Math fonts rarely (never?) have small caps, because they're not intended for use as a text font.

When writing algorithm (using algorithmic:0.1.0), I meet such need:

#algorithm({
  import algorithmic: *
  Function("NewTime", args: ($t$,), {
    While(cond: $#CallI("CmpTime")[$t_"new"$ = #CallI("GetTime")[], $t$] != 1$, {
      Cmt[pause for a while and retry]
      State[*continue*]
    })
    Return[$t_"new"$]
  })
})

Where CallI will call smallcaps on function name "CmpTime". If using the default font, as you say, the smallcaps makes no effects. That's why I want to change font for smallcaps (by show rule) in math equations.

Though my need can be satisfied when that issue is resolved, I see that issue has been opened for a long time and seems not to be resolved in short time. Maybe just making smallcaps an element function could be a fast (and harmless?) solution.

[laurmaedje]

The reason why I didn't make smallcaps an element function is that in contrast to emph, strong, highlight, etc. it isn't really a semantic thing to apply, but rather a purely visual text property. So it should rarely make sense to make all smallcaps red. At this point, you are assigning some semantic meaning to it that should be expressed through a new function.

At the same time, I can see how it's useful to be able to process smallcaps with show rules, since sometimes the smallcaps are in a different font and that can't be selected automatically by Typst.

[Coekjan]

Thanks for your reply.

So it should rarely make sense to make all smallcaps red.

Yes, the example (fill smallcaps red) I post above is just to demo the show rule behavior.

The reason why I didn't make smallcaps an element function is that in contrast to emph, strong, highlight, etc. it isn't really a semantic thing to apply, but rather a purely visual text property... At this point, you are assigning some semantic meaning to it that should be expressed through a new function.

At the same time, I can see how it's useful to be able to process smallcaps with show rules, since sometimes the smallcaps are in a different font and that can't be selected automatically by Typst.

I agree with your opinion that smallcaps is a visual property, and still hope it an element function so that we can customize text font (or other styles) in smallcaps.