For handling  - (hyphen) characters in character classes, see Using character classes in perlrequick, which says in part:

The special character '-' acts as a range operator within character classes ...

If '-' is the first or last character in a character class, it is treated as an ordinary character.

(Note that if the class is negated as in  [^-...] the "first" character is the first one after the  ^ (tilde | caret (per hippo - thanks!)) class negation operator.)

See also a similar discussion in Using character classes in perlretut.

Update: And see also Bracketed Character Classes, Special Characters Inside a Bracketed Character Class and Character Ranges in perlrecharclass.