def foo
1,2
end
causes syntax error "unexpected ',', expecting keyword_end"
I'd think this is valid Ruby. What's wrong?
2 Answers
You're not returning an array.
You should have this:
def foo
[1, 2]
end
Ruby isn't expecting a comma (,) because it isn't valid syntax. Integers in a simple array should be surrounded by brackets as well as delineated by a comma.
Comments
If you used explicit return it will work.
def foo
return 1,2
end
But that wouldn't work with implicit return. To make it work with implicit return you need to give it [1, 2].
2 Comments
slowpoison
I mentioned "without 'return'", so I knew that return works. I'm wondering why the difference.
Arup Rakshit
@slowpoison That's how parser is written by Matz. :) I don't know the history behind this too, as I really never needed.
return 1,2works. Going by Ruby convention of omitting return, I'd think just1,2would work.returnfollowed by a comma separated list to return an array. Similarly if you have an assignment with a single variable on the left hand side (or a*variable) then this can assign an array too e.g.x = 1, 2. But there isn't a general syntax to make an array without the square brackets.