- * Returns +self+ with its elements sorted in place.
- *
- * With no block, compares elements using operator <tt>#<=></tt>
- * (see Comparable):
- *
- * a = 'abcde'.split('').shuffle
- * a # => ["e", "b", "d", "a", "c"]
- * a.sort!
- * a # => ["a", "b", "c", "d", "e"]
- *
- * With a block, calls the block with each element pair;
- * for each element pair +a+ and +b+, the block should return an integer:
- *
- * - Negative when +b+ is to follow +a+.
- * - Zero when +a+ and +b+ are equivalent.
- * - Positive when +a+ is to follow +b+.
- *
- * Example:
- *
- * a = 'abcde'.split('').shuffle
- * a # => ["e", "b", "d", "a", "c"]
- * a.sort! {|a, b| a <=> b }
- * a # => ["a", "b", "c", "d", "e"]
- * a.sort! {|a, b| b <=> a }
- * a # => ["e", "d", "c", "b", "a"]
- *
- * When the block returns zero, the order for +a+ and +b+ is indeterminate,
- * and may be unstable:
- *
- * a = 'abcde'.split('').shuffle
- * a # => ["e", "b", "d", "a", "c"]
- * a.sort! {|a, b| 0 }
- * a # => ["d", "e", "c", "a", "b"]