Scarab

Scarab is an interpreted Lisp-family language with focuses on:

• Easy and fluid metaprogramming
• Clear syntax
• Rapid startup time

Building

First, make sure that you have CMake, Glib and its development headers installed.

Then, create a build directory and compile:

$ mkdir build
$ cd build
$ cmake ..
$ make

The interpreter will then be at build/scarab.

Language basics

The most noticeable addition to Scarab's syntax, as compared to other Lisp-like languages, is two new list syntaxes. The classic syntax for a list still works as expected:

> '(a b 1 2)
(a b 1 2)

But there are two new kinds of lists: an operator list and a form list.

Mathematical operators in Lisp have always been awkward, as infix operator notation is used in almost every other setting. In Scarab, a list surrounded in square brackets will be interpreted in infix notation:

> '[a + b]
(+ a b)

This works for multiple arguments and for nested expressions:

> '[a + b + c]
(+ a b c)
> '[[a * 3] + d]
(+ (* a 3) d)

This isn't a full expression parser, so [a * 3 + d] will not work; all of the operators in such a list must be the same.

Form lists, surrounded by curly braces, allow cleaner definition of sequences of forms (or statements):

> '{foo 1 2, bar 3 4}
((foo 1 2) (bar 3 4))

Each of the lists within the top level list is separated by commas or newlines:

> '{
    foo 1 2
    bar 3 4
}
((foo 1 2) (bar 3 4))