Ruby Fundamental - Blocos em Ruby (parte I)

blocos_1.rb

greet { puts "Hello" }

blocos_2.rb

verbose_greet("PuneRuby") { puts "Hello" }

blocos_3.rb

def call_block
  puts "Start of method"
  yield
  yield
  puts "End of method"
end  

call_block { puts 'In the block' }

blocos_4.txt

Start of method
In the block
In the block
End of method

blocos_5.txt

no block given (LocalJumpError)

blocos_6.rb

def call_block
  yield("hello", 99)
end

call_block { |str, num| puts str + " " + num.to_s}

blocos_7.txt

hello 99

blocos_8.rb

def try
  if block_given?
    yield
  else
    puts "no block"
  end
end  

try # => "no block"
try { puts "hello" } # => "hello"  

try do
  puts "hello"
end
# => "hello"