<h1>Hello! You requested <?fnl (echo ngx.var.uri) ?></h1>FHP Is a tool for embedding the Fennel lisp language into HTML templates inside of an Open Resty application.
It is inspired by PHP and other CGI frameworks of days gone by. It is meant as a fun tool to enjoy building simple web applications.
I made this in an afternoon for fun, I plan to rebuild my personal website among a few other things in it. I'm not sure if this is a stupid idea or not yet. Have fun and let me know what you think!
The easiest way to get started is to clone this repo and use the example folder as a starting point. Consult the opnresty docs if you are not sure how to run the application. I have included start and stop shell scripts that may need to be modified based on your openresty installation.
./fhp compile test.fhpThe FHP compiler is extremely simple. It takes input in the form of HTML with <?fnl/?> tags inside of it and translates it into valid fennel code. Anything not inside of a <?fnl/?> tag is wrapped in a call to echo, and everything inside of a <?fnl/?> tag is inserted into the output as is.
For example, the above code will compile to:
(echo "<h1>Hello! You requested ")
(echo ngx.var.uri)
(echo "</h1>")The FHP compiler is very forgiving in that it does not check your fennel code for syntax errors, this job is left up to the fennel compiler. This makes it possible to embed html inside of your s-expressions for doing things such as logic and iteration within your FHP templates.
<?fnl (when foo ?>
<p>Foo is true!</p>
<?fnl ) ?><?fnl
(local data [{:foo :bar} {:foo :baz}])
(each [ix row (ipairs data)]
?>
<div>
<p>Foo is <?fnl (echo row.foo) ?></p>
</div>
<?fnl )?><?fnl
(fn even-odd-display [n]
?>
<div class="even-odd">
<p><?fnl (echo n) ?> is <?fnl (echo (if (= 0 (% n 2)) "even" "odd")) ?></p>
</div>
<?fnl ) ?>
<?fnl (for [i 1 10] (even-odd-display i)) ?>echo is an alias for ngx.say and can be overridden by passing an emit-symbol string in the options table.
The only builtin other than echo right now is the dofile function, which is similar to lua or fennel's dofile except it expects a path to a fhp file and an optional environment table. This is useful for creating layout files, such as a header/footer, and small reusable components that can accept parameters.
For example:
<?fnl (dofile :header.fhp) ?>
<?fnl (dofile :page-template.fhp {:title "Home"}) ?>
<p>Lorum ipsum</p>
<?fnl (dofile :footer.fhp) ?>
I am in the process of modifying emacs mhtml-mode to enable a good editing experience. Any pointers from more experienced emacsers would be welcomed.
I like the idea of a shorthand syntax for for data binding, since this is the primary use case for such a templating language anyways. Perhaps .
I am not sure that I like the current syntax for nesting html inside of s-expressions. I think that this will create more headaches than it is worth. I think that long term, it might be best to introduce macros that allow you to stay in lisp land and still render your HTML inside of s-expressions.