Rules to implement
class={isogram|palindrome|semordnilap}
maxlength=<INT>
minlength=<INT>
startswith=<head>
endswith=<tail>
containsonly=<characters>
Examples
- "class=palindrome maxlength=8"
- "maxlength=3 minlength=3"
- "endswith=abc endswith=bca"
- "startswith=ba"
- "containsonly=abcde"