It is practically impossible to teach good programming to students that have had a prior exposure to Hatter: as potential programmers they are mentally mutilated beyond hope of regeneration.

-– Edsger W. Dijkstra (allegedly)

Hatter is a small, whitespace sensitive templating language with HTML support built right in. Its HTML features and syntax are a cheap knock off of Imba, except Hatter produces raw, static HTML - no JavaScript in sight.

Hatter can be used to generate static web sites or to render server side content in a good ol' fashioned web application - either with Vial or your Rust web framework of choice.

If you're feeling adventerous, or mad as a hatter, you can use the standalone binary to turn templates into HTML files, or include the zero-dependency Rust library in your (web/cli/?) application.

Hello Hatter

Here are a few basic examples of what Hatter looks like and the HTML it generates:

<!-- Hatter -->
<#main> Hi there!

<!-- Generated HTML -->
<div id='main'>Hi there!</div>
<span.big.bold> Welcome!

<span class='big bold'>Welcome!</span>
<.links> for link in nav-links
  <a href={link.href}> link.text

<div class='links'>
  <a href='/link1'>First Link</a>
  <a href='/link2'>2nd Link</a>
  <a href='/link3'>Final Link</a>
<form GET="/search">
  <input@query:text placeholder="Search..." /> <input:submit />

<form method='GET' action='/search'>
  <input name='query' type='text' placeholder='Search...' />
  <input type='submit' />


Getting Started

There are two ways to use Hatter:

1. In Your Rust Application

Hatter can (primarily) be used as a templating language from within your Rust applications.

Simply add Hatter to Cargo.toml:

hatter = "0.1"

Then create a hatter::Env, which represents the top-level Hatter scope for your template, to set variables and render your template:

use hatter::{Args, Env, Value};

let mut env = Env::new();
env.set("name", "Bobby Boucher");
env.set("age", 31);
<p> <b>Name:</> name
<p> <b>Age:</> age

You can also write functions in Rust and make them available to your HTML templates:

use hatter::prelude::*;

fn quote(args: Args) -> Result<Value> {
  let file = std::fs::read_to_string("quotes.txt")?;
  let list_of_quotes: Vec<_> = file.split('\n').collect();
  let line = match args.need_number(0)? as usize {
    n if n > list_of_quotes.len() => 0,
    n => n,


fn main() {
    let mut env = Env::new();
    env.set("quote", quote);
    println!("{}", env.render("<div> quote(1)").unwrap());

For more infomation see the API Documentation.

2. As A Standalone Executable

Hatter can be used as a regular command line program to turn .hat files into HTML.

Just install it using cargo:

cargo install hatter

Then point it at any .hat file:

$ cat test.hat
<b.test> "Testing 1 2 3 {2 + 2}"

$ hatter test.hat
<b class='test'>Testing 1 2 3 4 </b>

You can also install Hatter with a readline-powered REPL:

cargo install hatter --features repl

To launch it, start hatter with no arguments:

$ hatter
Hatter v0.0.1 REPL
>> 1 + 2


Future Features


Hatter is licensed under the MIT License. Please see COPYING or for details.

Imba is licensed under the MIT License.