Question

I saw this excerpt in the agile rails programming book:

module StoreHelper 
def page_title 
@page_title || "Pragmatic Store" 
end 
end 

Can I change || to =?

Answer 1

The longer answer is that you’ve stumbled on a programming style which is popular because it’s very concise, yet still easy to understand. It’s a shortcut way to write:

if ! @page_title.nil?
  return @page_title
else
  return "Pragmatic Store"
end

So that one line with logical or’s removes the need for an if/then. It does this because of the way that || is evaluated: from left-to-right, stopping at the first item that’s not false. The example you found also leaves out the return keyword, because it’s not explicitly necessary here.