path: root/docs/tutorial/4-template.md

---
description: Typst's tutorial.
---

# Making a Template
In the previous three chapters of this tutorial, you have learned how to write a
document in Typst, apply basic styles, and customize its appearance in-depth to
comply with a publisher's style guide. Because the paper you wrote in the
previous chapter was a tremendous success, you have been asked to write a
follow-up article for the same conference. This time, you want to take the style
you created in the previous chapter and turn it into a reusable template. In
this chapter you will learn how to create a template that you and your team can
use with just one show rule. Let's get started!

## A toy template { #toy-template }
In Typst, templates are functions in which you can wrap your whole document. To
learn how to do that, let's first review how to write your very own functions.
They can do anything you want them to, so why not go a bit crazy?

```example
#let amazed(term) = box[✨ #term ✨]

You are #amazed[beautiful]!
```

This function takes a single argument, `term`, and returns a content block with
the `term` surrounded by sparkles. We also put the whole thing in a box so that
the term we are amazed by cannot be separated from its sparkles by a line break.

Many functions that come with Typst have optional named parameters. Our
functions can also have them. Let's add a parameter to our function that lets us
choose the color of the text. We need to provide a default color in case the
parameter isn't given.

```example
#let amazed(term, color: blue) = {
  text(color, box[✨ #term ✨])
}

You are #amazed[beautiful]!
I am #amazed(color: purple)[amazed]!
```

Templates now work by using an "everything" show rule that applies the custom
function to our whole document. Let's do that with our `amazed` function.

```example
>>> #let amazed(term, color: blue) = {
>>>   text(color, box[✨ #term ✨])
>>> }
#show: amazed
I choose to focus on the good
in my life and let go of any
negative thoughts or beliefs.
In fact, I am amazing!
```

Our whole document will now be passed to the `amazed` function, as if we
wrapped it around it. This is not especially useful with this particular
function, but when combined with set rules and named arguments, it can be very
powerful.

## Embedding set and show rules { #set-and-show-rules }
To apply some set and show rules to our template, we can use `set` and `show`
within a content block in our function and then insert the document into
that content block.

```example
#let template(doc) = [
  #set text(font: "Inria Serif")
  #show "something cool": [Typst]
  #doc
]

#show: template
I am learning something cool today.
It's going great so far!
```

Just like we already discovered in the previous chapter, set rules will apply to
everything within their content block. Since the everything show rule passes our
whole document to the `template` function, the text set rule and string show
rule in our template will apply to the whole document. Let's use this knowledge
to create a template that reproduces the body style of the paper we wrote in the
previous chapter.

```example
#let conf(title, doc) = {
  set page(
    paper: "us-letter",
>>> margin: auto,
    header: align(
      right + horizon,
      title
    ),
<<<     ...
  )
  set par(justify: true)
  set text(
    font: "Libertinus Serif",
    size: 11pt,
  )

  // Heading show rules.
<<<   ...
>>>  show heading.where(
>>>    level: 1
>>>  ): it => block(
>>>    align(center,
>>>      text(
>>>        13pt,
>>>        weight: "regular",
>>>        smallcaps(it.body),
>>>      )
>>>    ),
>>>  )
>>>  show heading.where(
>>>    level: 2
>>>  ): it => box(
>>>    text(
>>>      11pt,
>>>      weight: "regular",
>>>      style: "italic",
>>>      it.body + [.],
>>>    )
>>>  )

  columns(2, doc)
}

#show: doc => conf(
  [Paper title],
  doc,
)

= Introduction
#lorem(90)

<<< ...
>>> == Motivation
>>> #lorem(140)
>>>
>>> == Problem Statement
>>> #lorem(50)
>>>
>>> = Related Work
>>> #lorem(200)
```

We copy-pasted most of that code from the previous chapter. The only two
differences are that we wrapped everything in the function `conf` and are
calling the columns function directly on the `doc` argument as it already
contains the content of the document. Moreover, we used a curly-braced code
block instead of a content block. This way, we don't need to prefix all set
rules and function calls with a `#`. In exchange, we cannot write markup
directly into it anymore.

Also note where the title comes from: We previously had it inside of a variable.
Now, we are receiving it as the first parameter of the template function.
Thus, we must specify it in the show rule where we call the template.

## Templates with named arguments { #named-arguments }
Our paper in the previous chapter had a title and an author list. Let's add these
things to our template. In addition to the title, we want our template to accept
a list of authors with their affiliations and the paper's abstract. To keep
things readable, we'll add those as named arguments. In the end, we want it to
work like this:

```typ
#show: doc => conf(
  title: [Towards Improved Modelling],
  authors: (
    (
      name: "Theresa Tungsten",
      affiliation: "Artos Institute",
      email: "tung@artos.edu",
    ),
    (
      name: "Eugene Deklan",
      affiliation: "Honduras State",
      email: "e.deklan@hstate.hn",
    ),
  ),
  abstract: lorem(80),
  doc,
)

...
```

Let's build this new template function. First, we add a default value to the
`title` argument. This way, we can call the template without specifying a title.
We also add the named `authors` and `abstract` parameters with empty defaults.
Next, we copy the code that generates title, abstract and authors from the
previous chapter into the template, replacing the fixed details with the
parameters.

The new `authors` parameter expects an [array] of [dictionaries]($dictionary)
with the keys `name`, `affiliation` and `email`. Because we can have an
arbitrary number of authors, we dynamically determine if we need one, two or
three columns for the author list. First, we determine the number of authors
using the [`.len()`]($array.len) method on the `authors` array. Then, we set the
number of columns as the minimum of this count and three, so that we never
create more than three columns. If there are more than three authors, a new row
will be inserted instead. For this purpose, we have also added a `row-gutter`
parameter to the `grid` function. Otherwise, the rows would be too close
together. To extract the details about the authors from the dictionary, we use
the [field access syntax]($scripting/#fields).

We still have to provide an argument to the grid for each author: Here is where
the array's [`map` method]($array.map) comes in handy. It takes a function as an
argument that gets called with each item of the array. We pass it a function
that formats the details for each author and returns a new array containing
content values. We've now got one array of values that we'd like to use as
multiple arguments for the grid. We can do that by using the
[`spread` operator]($arguments). It takes an array and applies each of its items
as a separate argument to the function.

The resulting template function looks like this:

```typ
#let conf(
  title: none,
  authors: (),
  abstract: [],
  doc,
) = {
  // Set and show rules from before.
<<<   ...

  set align(center)
  text(17pt, title)

  let count = authors.len()
  let ncols = calc.min(count, 3)
  grid(
    columns: (1fr,) * ncols,
    row-gutter: 24pt,
    ..authors.map(author => [
      #author.name \
      #author.affiliation \
      #link("mailto:" + author.email)
    ]),
  )

  par(justify: false)[
    *Abstract* \
    #abstract
  ]

  set align(left)
  columns(2, doc)
}
```

## A separate file { #separate-file }
Most of the time, a template is specified in a different file and then imported
into the document. This way, the main file you write in is kept clutter free and
your template is easily reused. Create a new text file in the file panel by
clicking the plus button and name it `conf.typ`. Move the `conf` function
definition inside of that new file. Now you can access it from your main file by
adding an import before the show rule. Specify the path of the file between the
`{import}` keyword and a colon, then name the function that you
want to import.

```example:single
>>> #let conf(
>>>   title: none,
>>>   authors: (),
>>>   abstract: [],
>>>   doc,
>>> ) = {
>>>  set text(font: "Libertinus Serif", 11pt)
>>>  set par(justify: true)
>>>  set page(
>>>    "us-letter",
>>>    margin: auto,
>>>    header: align(
>>>      right + horizon,
>>>      title
>>>    ),
>>>    numbering: "1",
>>>  )
>>>
>>>  show heading.where(
>>>    level: 1
>>>  ): it => block(
>>>    align(center,
>>>      text(
>>>        13pt,
>>>        weight: "regular",
>>>        smallcaps(it.body),
>>>      )
>>>    ),
>>>  )
>>>  show heading.where(
>>>    level: 2
>>>  ): it => box(
>>>    text(
>>>      11pt,
>>>      weight: "regular",
>>>      style: "italic",
>>>      it.body + [.],
>>>    )
>>>  )
>>>
>>>  set align(center)
>>>  text(17pt, title)
>>>
>>>  let count = calc.min(authors.len(), 3)
>>>  grid(
>>>    columns: (1fr,) * count,
>>>    row-gutter: 24pt,
>>>    ..authors.map(author => [
>>>      #author.name \
>>>      #author.affiliation \
>>>      #link("mailto:" + author.email)
>>>    ]),
>>>  )
>>>
>>>  par(justify: false)[
>>>    *Abstract* \
>>>    #abstract
>>>  ]
>>>
>>>  set align(left)
>>>  columns(2, doc)
>>>}
<<< #import "conf.typ": conf
#show: doc => conf(
  title: [
    Towards Improved Modelling
  ],
  authors: (
    (
      name: "Theresa Tungsten",
      affiliation: "Artos Institute",
      email: "tung@artos.edu",
    ),
    (
      name: "Eugene Deklan",
      affiliation: "Honduras State",
      email: "e.deklan@hstate.hn",
    ),
  ),
  abstract: lorem(80),
  doc,
)

= Introduction
#lorem(90)

== Motivation
#lorem(140)

== Problem Statement
#lorem(50)

= Related Work
#lorem(200)
```

We have now converted the conference paper into a reusable template for that
conference! Why not share it in the [Forum](https://forum.typst.app/) or on
[Typst's Discord server](https://discord.gg/2uDybryKPe) so that others can use
it too?

## Review
Congratulations, you have completed Typst's Tutorial! In this section, you have
learned how to define your own functions and how to create and apply templates
that define reusable document styles. You've made it far and learned a lot. You
can now use Typst to write your own documents and share them with others.

We are still a super young project and are looking for feedback. If you have any
questions, suggestions or you found a bug, please let us know
in the [Forum](https://forum.typst.app/),
on our [Discord server](https://discord.gg/2uDybryKPe),
on [GitHub](https://github.com/typst/typst/),
or via the web app's feedback form (always available in the Help menu).

So what are you waiting for? [Sign up](https://typst.app) and write something!