// file:    toBinaryLSBF.rex
// author:  Robert Keller
// purpose: to convert a number to a list of its binary bits, 
//          least-significant bit first

toBinaryLSBF(0) => [0];
toBinaryLSBF(N) => toBinaryLSBFaux(N);

toBinaryLSBFaux(0) => [];
toBinaryLSBFaux(N) => [N%2 | toBinaryLSBFaux(N/2)];

// Rationale: The number 0 is handled specially, since we don't want
// 0 to be converted to [] (no bits).

// N%2 gives the least-significant bit of N; 
// N/2 is truncating integer arithmetic, which effectively shifts the binary
// representation one place to the right, losing the LSB.
// Calling toBinaryLSBFaux recursively does the rest.

test() = map(toBinaryLSBF, range(0, 16));