Implementing LaTeX macros unsupported by Typst

Background

There is not always a Typst equivalent for every LaTeX macro. This document provides a guide on how to implement unsupported LaTeX macros in Typst.

The \mathscr macro

LaTeX: \mathscr

Implementation in Typst ^[1]

#let scr(it) = text(
  features: ("ss01",),
  box($cal(it)$),
)

Usage example:

$
y = scr(A) x
$

The \LaTeX and \TeX macro

LaTeX: \LaTeX and \TeX

Implementation in Typst ^[2]

#let TeX = context {
  set text(font: "New Computer Modern")
  let e = measure("E")
  let T = "T"
  let E = text(1em, baseline: e.height * 0.31, "E")
  let X = "X"
  box(T + h(-0.15em) + E + h(-0.125em) + X)
}

#let LaTeX = context {
  set text(font: "New Computer Modern")
  let a-size = 0.66em
  let l = measure("L")
  let a = measure(text(a-size, "A"))
  let L = "L"
  let A = box(scale(x: 105%, text(a-size, baseline: a.height - l.height, "A")))
  box(L + h(-a.width * 0.67) + A + h(-a.width * 0.25) + TeX)
}

Usage example:

You can use #LaTeX in text environments.
You can use $#LaTeX$ in math environments as well.

Using the op function to define custom operators

For example, if you want to define a custom operator \myopr.

LaTeX: \newcommand{\myopr}{\operatorname{myopr}}

Equivalent in Typst:

#let myopr = op("myopr");

Usage example:

$
y = myopr x
$

A vertical bar for evaluation

It's common to use a vertical bar to denote the evaluation of a function at a point. e.g.

➣ LaTeX:

f(x) \bigg\rvert_{x = x_0}

Where \bigg\rvert may be replaced with \bigg\vert, \bigg| etc.

➣ Walkaround in Typst:

f(x) lr(| vec(delim: #none, , , x = x_0))

Also it's common to use a vertical bar to denote the deference of function values at two points, especially when calculating definite integrals. e.g. ^[3]

➣ LaTeX:

F(x) \bigg\rvert_{a}^{b}

Where \bigg\rvert may be replaced with \bigg\vert , \bigg| etc.

➣ Walkaround in Typst:

F(x) lr(| vec(delim: #none, b, , a))

The \cancelto macro

\cancelto{value}{expression} is a LaTeX command provided by the cancel package. It is used to place an arrow through an expression and annotate it with a value to which the expression is be evaluated.

➣ LaTeX:

\cancelto{0}{\frac{\partial^2 Q}{\partial r^2}}

➣ Implementation in Typst (adapted from ^[4] ):

#let cancelto(to, body) = {
  let max(a, b) = if a > b { a } else { b };
  context {
    let m = measure(body)
    let (w, h) = (m.width, m.height * 2)
    let arrow = rotate(-55deg, math.stretch(sym.arrow.r, size: max(h*1.8, w*2.0)))
    set place(center + horizon)
    body
    place(dx: -w * 0.5, dy: -h * 0.1, arrow)
    place(dx: w * 0.3, dy: -h * 1.1, to)
  }
}

➣ Usage example:

$
cancelto(0, (diff^2 Q)/(diff r^2))
$

References and Credits

The following resources were used to create this document:

1. \mathscr: Variants Functions – Typst Documentation ↩︎

2. \TeX and \LaTeX: How do I insert the LaTeX symbol in Typst? · typst/typst · Discussion #1732 ↩︎

3. \bigg\rvert for evaluation: Math symbol: Vertical bar for ''evaluated at …'' Limits are not apart enough - TeX - LaTeX Stack Exchange ↩︎

4. \cancelto: Is there an equivalent to Latex's \cancelto in Typst? - Questions - Typst Forum ↩︎