Share the internal counter with other environments

[zhangchiqft]

Dear Author,

Thanks for this wonderful package, I would like to know whether it is possible to share the internal counter with other environments, say equation?

For example, to have the following display

Best regards,
Chi Zhang

[quachpas]

Hello @zhangchiqft! Yes it is possible, see the manual for more details.
If environments share the same identifier, then they also share the same counter, e.g.,

#let theorem = thmbox(
 "theorem", // identifier
 "Theorem", // head
 fill: rgb("#e8e8f8")
)
#let lemma = thmbox(
 "theorem", // identifier - same as that of theorem
 "Lemma", // head
 fill: rgb("#efe6ff")
)

[zhangchiqft]

Hello @zhangchiqft! Yes it is possible, see the manual for more details. If environments share the same identifier, then they also share the same counter, e.g.,

#let theorem = thmbox(
 "theorem", // identifier
 "Theorem", // head
 fill: rgb("#e8e8f8")
)
#let lemma = thmbox(
 "theorem", // identifier - same as that of theorem
 "Lemma", // head
 fill: rgb("#efe6ff")
)

Thank you for your reply! I'm familiar with that approach. My real question is: how can I share this counter with other environments, such as equations?"

[quachpas]

I misunderstood your question, sorry!
I don't think it's possible without heavily modifying chteorems. If I understand correctly, the lib uses an internal state counter thm-counters.

Instead, if you follow the ams template way using basic figures + a show rule, you can have

#theorem("FooBar")[#lorem(20)]
$ f(x,y) $
#proposition("BarFoo")[#lorem(30)]

Obviously, you lose all the advantages of using a lib, i.e., you have to reimplement every feature.

Details below :)

#let thm-numbering(..numbers) = {
  let update = counter(math.equation).step()
  let n = counter(math.equation).get()
  return update + numbering("1.1", ..n)
}
#let eq-numbering(..numbers) = {
  let thm = figure.where(kind: "maths")
  let update = counter(thm).step()
  let n = counter(thm).get()
  return update + numbering("1.1", ..n)
}

and you can set both numbering for theorems and equations.

#set math.equation(numbering: eq-numbering)
#let theorem(caption, body) = figure(
  body,
  caption: caption,
  kind: "maths",
  supplement: "Theorem",
  numbering: thm-numbering,
)
... // Proposition etc.

Then define your theorem-body

#show figure.where(kind: "maths"): theorem-body
#let theorem-body(fig) = {
  let kind = lower(fig.supplement.text) //  string
  let prefix = { // content
    fig.supplement
    " "
    fig.caption.counter.display(fig.numbering)
    ": "
    text(weight: "regular", fig.caption.body)
  }
  let body = {
    fig.body
  }
  return strong(prefix) + "\n" + body
}

See ams template

[jbirnick]

You can have a look at great-theorems, which separates the counter functionality from the theorem functionality.

For the counter functionality you can use one of the two packages rich-counters or headcount.