moonpug

<ul>
{% for b in books %}
  <li>{{ b.title }}</li>
{% endfor %}
</ul>

ul
  each b in books
    li= b.title

{% for b in books %}
- {{ b.title }}
{% endfor %}

let out = @moonpug.render("Hello {{ name|title }}!", { "name": "ada" })
// Hello Ada!

#Install

moon add moonbitstack/moonpug

import {
  "moonbitstack/moonpug",
}

#A first page

struct Book {
  title : String
  year : Int
  tags : Array[String]
} derive(ToJson)

struct Shelf {
  shelf : String
  books : Array[Book]
} derive(ToJson)

let page =
  #|<h1>{{ shelf }}</h1>
  #|<ul>{% for b in books|sort(attribute='year') %}
  #|  <li>{{ b.title }}, {{ b.year }}{% if b.tags %} ({{ b.tags|join(', ') }}){% endif %}</li>
  #|{% endfor %}</ul>
let html = @moonpug.render(page, Shelf::{ shelf: "Reading <list>", books: [...] })

#Three languages

let data : Json = { "title": "Notes", "items": ["ink", "paper"] }
@moonpug.render("h1= title\neach i in items\n  p= i", data, format=@moonpug.pug)
// <h1>Notes</h1><p>ink</p><p>paper</p>

#Language blocks

<section>
{% block lang=pug %}
ul
  each i in items
    li= i
{% endblock %}
</section>

#What a template can say

#Data, functions and objects

let env = @moonpug.Env::new()
env.add_global("today", @moonpug.Value::func("today", (_, _, _) => Text("2026-10-25")))
env.add_filter("money", (call, value, _, _) => Text("¥" + call.text(value)))
env.add_test("short", (call, value, _) => call.text(value).length() <= 3)

impl @moonpug.Object for Cart with fn kind(_) { "the cart" }
impl @moonpug.Object for Cart with fn attr(self, name) { ... }     // cart.total
impl @moonpug.Object for Cart with fn items(self) { ... }          // for x in cart
impl @moonpug.Object for Cart with fn assign(self, name, value) { ... }  // {% set cart.coupon = … %}

env.compile(source).render_values({ "cart": Object(cart) })

#Templates by name

let env = @moonpug.Env::new(load=name => sources.get(name))
let page = env.template("page.html")   // read, compiled and kept
page.render(data)

#What the program answers

let host : @moonpug.Host = {
  url: Some((name, args, named) => routes.url(name, args, named)),
  asset: Some(path => "/static/" + path),
  asset_prefix: Some(() => "/static/"),
  media_prefix: Some(() => "/media/"),
  csrf_token: Some(() => forms.token()),
  now: Some(() => clock.now_iso()),
}
@moonpug.Env::new().add_host(host~)

#Your own language

fn read_csv(source : String, reading : @moonpug.Reading) -> Array[@syntax.Node] raise @moonpug.Refused {
  ...
  nodes.append(reading.block(cell, "html", None, reading.line))   // cells read as HTML
  ...
}

env.add_lang({ name: "csv", aliases: ["table"], options: @syntax.options, read: read_csv })

#Settings

#Configuration precedence

library preset  <  the record you pass  <  the same name passed to this call

#Delimiters and shorthands

let square = { ..@moonpug.delimiters, variable_start: "[[", variable_end: "]]" }
@moonpug.render("Hi [[ name ]]! {{ stays }}", { "name": "Ada" }, delimiters=square)
// Hi Ada! {{ stays }}

let settings = {
  ..@moonpug.settings,
  shortcuts: Map([(".", "class"), ("#", "id"), ("@", "data-role")]),
}

#Bounded output

#Errors

page.html:3: price is undefined

#Examples

moon run src/examples/01-first-page
moon run src/examples/02-three-languages
moon run src/examples/03-template-set
moon run src/examples/04-own-language
moon run src/examples/05-host-objects
moon run src/examples/06-minimal-site
moon run src/examples/07-feature-tour
moon run src/examples/08-application

#Licence