Omitting "return" from last line of a method def

1

I find myself in position of an old copy of SAMS TY Ruby in 21 Days; written in regard to Ruby version 1.7

I have version 2.7.2p137 installed and I am getting by OK (in the first few chapters anyway). The book claims that a method that doesn’t contain a line with “return” in it will go ahead and return the last expression it evaluates, so that

def sumdiff(n1, n2)
	n1+n2, n1-n2
end

will return (keep up with me) 18, 2 if given the arguments 10, 8.

But when I tried running that I got
syntax error, unexpected ‘,’, expecting `end’
n1+n2, n1-n2

And then it worked fine once I reran it with “return” where it should be.

Was this functional "return"lessness a feature in Ruby 1.7 that was later removed? Or am I still doing something wrong?

2

When you use return, you pass 2 arguments and you get an array. But if you omit return, you end up with something that makes no sense to Ruby.

If you type 1, 2 in bare Ruby, you get syntax error, because 1, 2 means nothing. You instead meant [1, 2].

Similarly, you need to return this:

[n1+n2, n1-n2]

In case of return, it accepts *args (multiple arguments), and returns the *args as an array for you. You can omit return, but you need to surround values in arrays if you are planning to return multiple values.

3

Thank you Sourav!! Indeed the SAMS book got it wrong : /