Fern is a programmable data description/generation language. Besides
the standard primitive data types, maps and lists, it has control/generative
structures like conditionals, let-blocks, loops, and functions. It is
meant to have a clean syntax, and to be amenable to different syntaxes.

For example you can (or will be able to do) things like:

let include_foo_stuff = True in
    objects = ['fruz' 5 if include_foo_stuff then 'foo' bar' end 'quux']
end

objects2 = [for obj in objects put obj + '2' end 'I get added']

If you don't care about the philosophy, just go to the examples directory.

Fern was first inspired by my attempts to use Lua to generate SVG files with
significant random components. Using Lua's control structures didn't feel
quite natural. I had the idea of writing a vector graphics format with
control structures, variables, and conditionals baked in. At other times,
I've had data where I wished parts of it could be automatically generated
from other parts. XML is a natural fit for some things, but it's far too
verbose for my tastes. I slowly realized a single language might be able to
satisfy all these itches. Fern is my attempt to create this language.

I envision, among other things, using Fern to generate CSS (don't you wish
you could have variables in CSS?), a build system (I always wanted to try
one), a data format for a music-editor, among others.

If that sounds absurdly ambitious, I'd be inclined to agree. Or maybe I'll
just re-invent Lisp.  We'll have to see how it actually works out. But I
think it will be cool.