From: Jeff Davis <jdavis-list@...>
Date: 2005-01-30T07:34:10+09:00
Subject: pass block to a method call?

I know I can define a method like:

def foo(&p)
    p.call
end

or:

def foo
    yield
end

First, what's the difference between those two? I can pass a block to 
either.

Also, how do I make the block optional? I would like to make a method 
that performs it's task as usual, but you could also pass it a block 
that it can use.

And also, can you pass more than one block to the same method? Is it 
only the last argument?

And what's the difference between:
proc { puts 'foo'}
and:
{ puts 'foo' }
?

Is "proc" a keyword that turns the block into a value, or is the block 
already a value and it's being passed to "proc" to turn it into a Proc 
object?

Perhaps I'm not understanding blocks and iterators all that well.

Thanks,
    Jeff Davis