Algo

A Typst library for writing algorithms. On Typst v0.6.0+ you can import the algo package:

#import "@preview/algo:0.3.4": algo, i, d, comment, code

Otherwise, add the algo.typ file to your project and import it as normal:

#import "algo.typ": algo, i, d, comment, code

Use the algo function for writing pseudocode and the code function for writing code blocks with line numbers. Check out the examples below for a quick overview. See the usage section to read about all the options each function has.

Examples

Here's a basic use of algo:

#algo(
  title: "Fib",
  parameters: ("n",)
)[
  if $n < 0$:#i\        // use #i to indent the following lines
    return null#d\      // use #d to dedent the following lines
  if $n = 0$ or $n = 1$:#i #comment[you can also]\
    return $n$#d #comment[add comments!]\
  return #smallcaps("Fib")$(n-1) +$ #smallcaps("Fib")$(n-2)$
]

Here's a use of algo without a title, parameters, line numbers, or syntax highlighting:

#algo(
  line-numbers: false,
  strong-keywords: false
)[
  if $n < 0$:#i\
    return null#d\
  if $n = 0$ or $n = 1$:#i\
    return $n$#d\
  \
  let $x <- 0$\
  let $y <- 1$\
  for $i <- 2$ to $n-1$:#i #comment[so dynamic!]\
    let $z <- x+y$\
    $x <- y$\
    $y <- z$#d\
    \
  return $x+y$
]

And here's algo with more styling options:

#algo(
  title: [                    // note that title and parameters
    #set text(size: 15pt)     // can be content
    #emph(smallcaps("Fib"))
  ],
  parameters: ([#math.italic("n")],),
  comment-prefix: [#sym.triangle.stroked.r ],
  comment-styles: (fill: rgb(100%, 0%, 0%)),
  indent-size: 15pt,
  indent-guides: 1pt + gray,
  row-gutter: 5pt,
  column-gutter: 5pt,
  inset: 5pt,
  stroke: 2pt + black,
  fill: none,
)[
  if $n < 0$:#i\
    return null#d\
  if $n = 0$ or $n = 1$:#i\
    return $n$#d\
  \
  let $x <- 0$\
  let $y <- 1$\
  for $i <- 2$ to $n-1$:#i #comment[so dynamic!]\
    let $z <- x+y$\
    $x <- y$\
    $y <- z$#d\
    \
  return $x+y$
]

 

Here's a basic use of code:

#code()[
  ```py
  def fib(n):
    if n < 0:
      return None
    if n == 0 or n == 1:        # this comment is
      return n                  # normal raw text
    return fib(n-1) + fib(n-2)
  ```
]

And here's code with some styling options:

#code(
  indent-guides: 1pt + gray,
  row-gutter: 5pt,
  column-gutter: 5pt,
  inset: 5pt,
  stroke: 2pt + black,
  fill: none,
)[
  ```py
  def fib(n):
      if n < 0:
          return None
      if n == 0 or n == 1:        # this comment is
          return n                # normal raw text
      return fib(n-1) + fib(n-2)
  ```
]

Usage

algo

Makes a pseudocode element.

algo(
  body,
  header: none,
  title: none,
  parameters: (),
  line-numbers: true,
  strong-keywords: true,
  keywords: _algo-default-keywords, // see below
  comment-prefix: "// ",
  indent-size: 20pt,
  indent-guides: none,
  indent-guides-offset: 0pt,
  row-gutter: 10pt,
  column-gutter: 10pt,
  inset: 10pt,
  fill: rgb(98%, 98%, 98%),
  stroke: 1pt + rgb(50%, 50%, 50%),
  radius: 0pt,
  breakable: false,
  block-align: center,
  main-text-styles: (:),
  comment-styles: (fill: rgb(45%, 45%, 45%)),
  line-number-styles: (:)
)

Parameters:

• body: content — Main algorithm content.

• header: content — Algorithm header. If specified, title and parameters are ignored.

• title: string or content — Algorithm title. Ignored if header is specified.

• Parameters: array — List of algorithm parameters. Elements can be string or content values. string values will automatically be displayed in math mode. Ignored if header is specified.

• line-numbers: boolean — Whether to display line numbers.

• strong-keywords: boolean — Whether to strongly emphasize keywords.

• keywords: array — List of terms to receive strong emphasis. Elements must be string values. Ignored if strong-keywords is false.

  The default list of keywords is stored in _algo-default-keywords. This list contains the following terms:

  ("if", "else", "then", "while", "for",
  "repeat", "do", "until", ":", "end",
  "and", "or", "not", "in", "to",
  "down", "let", "return", "goto")
  

  Note that for each of the above terms, _algo-default-keywords also contains the uppercase form of the term (e.g. "for" and "For").

• comment-prefix: content — What to prepend comments with.

• indent-size: length — Size of line indentations.

• indent-guides: stroke — Stroke for indent guides.

• indent-guides-offset: length — Horizontal offset of indent guides.

• row-gutter: length — Space between lines.

• column-gutter: length — Space between line numbers, text, and comments.

• inset: length — Size of inner padding.

• fill: color — Fill color.

• stroke: stroke — Stroke for the element's border.

• radius: length — Corner radius.

• breakable: boolean — Whether the element can break across pages. WARNING: indent guides may look off when broken across pages.

• block-align: none or alignment or 2d alignment — Alignment of the algo on the page. Using none will cause the internal block element to be returned as-is.

• main-text-styles: dictionary — Styling options for the main algorithm text. Supports all parameters in Typst's native text function.

• comment-styles: dictionary — Styling options for comment text. Supports all parameters in Typst's native text function.

• line-number-styles: dictionary — Styling options for line numbers. Supports all parameters in Typst's native text function.

i and d

For use in an algo body. #i indents all following lines and #d dedents all following lines.

comment

For use in an algo body. Adds a comment to the line in which it's placed.

comment(
  body,
  inline: false
)

Parameters:

• body: content — Comment content.

• inline: boolean — If true, the comment is displayed in place rather than on the right side.

  NOTE: inline comments will respect both main-text-styles and comment-styles, preferring comment-styles when the two conflict.

  NOTE: to make inline comments insensitive to strong-keywords, strong emphasis is disabled within them. This can be circumvented via the text function:

  #comment(inline: true)[#text(weight: 700)[...]]

no-emph

For use in an algo body. Prevents the passed content from being strongly emphasized. If a word appears in your algorithm both as a keyword and as normal text, you may escape the non-keyword usages via this function.

no-emph(
  body
)

Parameters:

• body: content — Content to display without emphasis.

code

Makes a code block element.

code(
  body,
  line-numbers: true,
  indent-guides: none,
  indent-guides-offset: 0pt,
  tab-size: auto,
  row-gutter: 10pt,
  column-gutter: 10pt,
  inset: 10pt,
  fill: rgb(98%, 98%, 98%),
  stroke: 1pt + rgb(50%, 50%, 50%),
  radius: 0pt,
  breakable: false,
  block-align: center,
  main-text-styles: (:),
  line-number-styles: (:)
)

Parameters:

• body: content — Main content. Expects raw text.

• line-numbers: boolean — Whether to display line numbers.

• indent-guides: stroke — Stroke for indent guides.

• indent-guides-offset: length — Horizontal offset of indent guides.

• tab-size: integer — Amount of spaces that should be considered an indent. If unspecified, the tab size is determined automatically from the first instance of starting whitespace.

• row-gutter: length — Space between lines.

• column-gutter: length — Space between line numbers and text.

• inset: length — Size of inner padding.

• fill: color — Fill color.

• stroke: stroke — Stroke for the element's border.

• radius: length — Corner radius.

• breakable: boolean — Whether the element can break across pages. WARNING: indent guides may look off when broken across pages.

• block-align: none or alignment or 2d alignment — Alignment of the code on the page. Using none will cause the internal block element to be returned as-is.

• main-text-styles: dictionary — Styling options for the main raw text. Supports all parameters in Typst's native text function.

• line-number-styles: dictionary — Styling options for line numbers. Supports all parameters in Typst's native text function.

Contributing

PRs are welcome! And if you encounter any bugs or have any requests/ideas, feel free to open an issue.