Brackets and character classes

• Brackets are no longer an enumerated character class

• Brackets are now used for grouping

• Enumerated character class is <[aeiou]> and <-[aeiou]>

• Use .. instead of - for ranges:

/ <[a-z]> /         # wrong
/ <[a..z]> /        # correct

• Whitespace is metasyntactic in character class

/ <[a e i o u]>  /  # vowels
/ <[aeiou]> /       # same