Harmonia's silly example

core.harm

### core.harm --- Harmonia's core library
# 
# This module provides the core functions from Harmonia implemented in
# Harmonia itself.

# Booleans are just plain functions, receiving two function bodies and
# calling the appropriate one.
let true [a {}, b {}] {
  call a
};

let false [a {}, b {}] {
  call b
}

# The plain `if' function works on top of the Boolean functions. The
# consequent block is always required.
let if [condition, consequent, otherwise {}] {
  condition  consequent
             otherwise
};

# Function application is performed by the special `apply' macro, which
# just un-slices the list.
macro apply [fn, parms] {
    ~fn ~parms
};


# Repetition constructions are based off recursion and the internal
# throw semantics. Other repetition structures are pilled on top of the
# core `loop' function.
#
# `break' is just a special function that throws itself.
let break { throw break };

let loop [block] {
    try {
        call block }
    catch matches break {
        call return }

    loop block;
};

let while [condition, block] {
    loop {
        condition block break }
};