def greet(name)      
    yield name
end

greet('calling a block using yield') { |x| puts x }

def greet(name, &block)      
    block.call(name)
end

greet('calling a &block using block.call') { |x| puts x }

def greet(name, proc)    
    proc.call(name)
end

greet('passing a proc', proc { |x| puts x })
greet('passing a lambda', lambda { |x| puts x })
greet('passing a -> (lambda shorhand)', -> (x) { puts x })