Ruby 1.9 hash with a dash in a key

Question

In ruby 1.9 there is a way to define this hash with the new syntax?

irb> { a:  2 }
=> {:a=>2}

irb> { a-b:  2 }
SyntaxError: (irb):5: syntax error, unexpected tLABEL
{ a-b:  2 }
      ^

with the old one, it's working:

irb> { :"a-b" =>  2 }
=> {:"a-b"=>2}

Answer 1

There are some legitimate symbols that cannot be used with the new syntax. I cannot find a reference, but it appears that a symbol name matching /[a-zA-Z_][a-zA-Z_0-9]*/ is allowed with the new syntax. If the symbol name contains special characters such as '-', you have to use the Ruby 1.8 syntax, :'my-symbol-name'