Unquiet

So… everything I’ve read about Ruby’s blocks seems too esoteric to me… here’s what it boils down to in my mind. See if it helps you…

def myMethod(id)
num = Model.find(id).number_of_items
yield
end

called like:

myMethod(id) { |val| val*2 }

is equivalent to:

def myMethod(id)
num = Model.find(id).number_of_items
num * 2
end

Blocks provide a simple way to change the way a method works by in-lining the code in the block (between the { and the }). If I wanted `myMethod` to triple the number_of_items value (retrieved from a database, maybe?), I could call it thusly:

myMethod(1) { |val| val*3 }

How might this be useful? Let’s say you wanted to retrieve a bunch of rows from a database based on an input value (x), but you needed to format the display differently at different times.

Write your method to take a block, pass the values into the block (that’s what the `|val|` is about, and manipulate within the block!

That’s the way my mind sees it. Maybe it’ll clarify blocks for other someone else, too?