How to achieve equivalent multline in LaTeX?

Questions
,
1

Is there anything in Typst (either in the core language or a package) that behaves as LaTeX’s multline? Eg from the amsmath manual,

screenshot_2025-05-27-144620

The functionality I want is the following: given a long equation,

  1. if broken in two parts, align left/right,
  2. if broken in three parts, align left/center/right.
2 
$
  a + b + c + d + & e + f             \
        + med i + & j + k + l + m + n
$
$
  a + b + c + & d + e             \
        + med & f + i             \
        + med & j + k + l + m + n
$

image
image275×146 6.79 KB

3

Thanks, I understand how to align things manually.

I am looking for a way to make Typst align the lines left/center/right.

4

How do you precisely define what counts as left/center/right align? Exact formula/definition/algorithm. It looks totally random to me. With manual alignment, you know exactly how to align the lines.

5

It seems clear to me from the first post: the line breaks are marked explicitly, then the first line should be fully on the left, the middle part centered (if any) and the right part fully on the right.

6

Left is all whitespace on the right, center is the same amount of whitespace on left & right, etc.

Are you familiar with \multline in LaTeX? Again, I am looking for something similar.

7

Ahhh, there is a width limit, now I see it. It’s so uneven, it doesn’t look like anything.

No.

8

I don’t know how to properly handle math, but this looks close enough:

#let multiline(body) = {
  show math.equation: it => {
    if it.body.func() != [].func() { return it }
    let parts = it.body.children.split(linebreak())
    if parts.len() not in (2, 3) { return it }
    set par(spacing: 1em)
    if parts.len() == 2 {
      let (a, b) = parts.map(array.join)
      align(left, $#a$)
      align(right, $#b$)
    } else {
      let (a, b, c) = parts.map(array.join)
      align(left, $#a$)
      $#b$
      align(right, $#c$)
    }
  }
  body
}

#block(width: 7cm, stroke: 1pt, {
  multiline[$
    a + b + c + d + e + f \
    + med i + j + k + l + m + n
  $]
  multiline[$
    a + b + c + d + e \
    + med f + i \
    + med j + k + l + m + n
  $]
})

#multiline[$
  a + b + c + d + e + f \
  + med i + j + k + l + m + n
$]
#multiline[$
  a + b + c + d + e \
  + med f + i \
  + med j + k + l + m + n
$]

image
image640×252 13.4 KB

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9

@Andrew, this is a bit more confrontational than it needs to be, please try to avoid that.

@Tamas_K_Papp did Andrew’s last response satisfy your use case? If if so, be sure to give it a checkmark :ballot_box_with_check:. This will help others find the solution in the future. If something is missing, please let us know what so we can resolve your issue. Thanks!

2 Likes
10

Since Andrew suggested that the solution “doesn’t properly handle math”, I am keeping the issue open in case someone suggests a better one (I don’t know enough about Typst to say if the solution ¨"properly" handles math).

1 Like
11

Here’s @Andrew’s answer adapted to produce block equations instead of inline equations (this also takes directly an equation as parameter instead of content):

#let align-eq(alignment, eq) = {
  show math.equation.where(block: true): set align(alignment)
  eq
}

#let multiline(it) = {
  if it.body.func() != [].func() { return it }
  let parts = it.body.children.split(linebreak())
  if parts.len() not in (2, 3) { return it }
  if parts.len() == 2 {
    let (a, b) = parts.map(array.join)
    align-eq(left, $ #a $)
    show math.equation.where(block: true): set block(above: 0.65em)
    align-eq(right, $ #b $)
  } else {
    let (a, b, c) = parts.map(array.join)
    align-eq(left, $ #a $)
    show math.equation.where(block: true): set block(above: 0.65em)
    align-eq(center, $ #b $)
    align-eq(right, $ #c $)
  }
}

#multiline($
  a + b + c + d + e + f \
  + med i + j + k + l + m + n
$)
#multiline($
  a + b + c + d + e \
  + med f + i \
  + med j + k + l + m + n
$)

However this has various problems, e.g. with equation numbering and in cases where “multiline” should be used for only a part of the whole equation. Also the question has come up before here. It would probably make sense to file a feature request.

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