Write a subroutine that swaps two arrays.

Write a subroutine that verifies that the argument is a correctly formed integer. For extra credit, give it a flag that lets it check for integers; floating-point numbers (with and without exponents); complex, hexadecimal, and octal numbers; or any combination of these.

Write a module to count the words, lines, and characters in a string.

Write a module to print a hash nicely. Handle the case when the values contain new lines. (For extra credit, handle the case when the value contains unprintable characters.)

Write a function to encode a string so that it may be enclosed in double quotes safely. For example:

This "string" contains a backslash ()

"This "string" contains a backslash (\)"

Write a function that decodes strings as well.