parenthesize argument(s)

So, I read somewhere that you don't have to parenthesize function
arguments in ruby. So then I'm in irb and I call puts Hello.say_hello
"Alex Egg" and it says, "warning: parenthesize argument(s) for future
version".

So what's the official word? Are non-parenthesized arguments being
deprecated in ruby?

You're calling two methods really:

puts(Hello.say_hello("Alex Egg"))

It complains if you just try:

puts Hello.say_hello "Alex Egg"