9.3 Cutting and Pasting Bit Strings
— procedure: bit-string-append bit-string-1 bit-string-2
Appends the two bit string arguments, returning a newly allocated bit
string as its result. In the result, the bits copied from
bit-string-1 are less significant (smaller indices) than those
copied from bit-string-2.
— procedure: bit-substring bit-string start end
Returns a newly allocated bit string whose bits are copied from
bit-string, starting at index start (inclusive) and ending
at end (exclusive).