Boot is used internally in Axiom for some of the interpreter and compiler code. Here is a detailed description of the Boot Language

This is a simple example of Boot programming.

Define a function.

pairBoot(a,b) ==
  a>b => [-b,-a]
  [a,b]

Value = T
Value = 432

Now call it.

pairBoot(1,4)$Lisp

(1)

map(integer,destruct(pairBoot(3,2)$Lisp))

(2)

That's my first Boot function!

You can now write for example:

foobar(x,y) == x + y

Value = T
Value = 304

And call it with

integer(foobar(2,3)$Lisp)

(3)