Hacker News Reader

Comment by old-gregg | Hacker News Reader

My personal up until recently underused keyword was (surprise!) "rescue".

I'm not sure how this has been escaping me since 07, but I had no idea you can apply it at the end of an expression, i.e. when you're facing nasty functions that insist on trhowing exceptions, instead of

begin

  value = function_that_throws

rescue

  value = "default"

end

you can just write:

value = function_that_throws rescue "default"

View on HN

Cool, sure, but blind rescues are as the crow flies to bugs: use them wisely, or use them _why-ly.

that's along the lines of using or for nil returns.

value = function_that_nils || "default"

I've found it makes code more succinct.

Careful here: I've seen plenty of "Rubiomatic" bugs that look like this:

value = function_that_nils or "default"

... which results in nil assignment to value. Accidental confusion between || and 'or' is very common in Ruby world IMO, almost like famous == vs = in C.

Agreed. I think one is for statements (or) and the other one is for expressions (||), so they have different operational precedence, even though you could use them interchangeably, as long as you knew what got executed first.

Reply on news.ycombinator.com