`binary-search``SEQUENCE``PROC`procedurePerforms a binary search in

`SEQUENCE`, which should be a sorted list or vector.`PROC`is called to compare items in the sequence, should accept a single argument and return an exact integer: zero if the searched value is equal to the current item, negative if the searched value is*less*than the current item, and positive otherwise. Returns the index of the found value or`#f`otherwise.`SEQUENCE`may also be an exact integer - in this case the search is performed on an /abstract/ sequence and`PROC`is called with the current index into the abstract sequence. This may be useful if you just want to iterate over the`O(log n)`steps needed to locate a value in some particular range.