详解Ruby中的块的知识

block_name{
  statement1
  statement2
  ..........
}

#!/usr/bin/ruby

def test
  puts "You are in the method"
  yield
  puts "You are again back to the method"
  yield
end
test {puts "You are in the block"}

You are in the method
You are in the block
You are again back to the method
You are in the block

#!/usr/bin/ruby

def test
  yield 5
  puts "You are in the method test"
  yield 100
end
test {|i| puts "You are in the block #{i}"}

You are in the block 5
You are in the method test
You are in the block 100

test {|i| puts "You are in the block #{i}"}

puts "You are in the block #{i}"

You are in the block 5

yield a, b

test {|a, b| statement}

#!/usr/bin/ruby

def test
 yield
end
test{ puts "Hello world"}

#!/usr/bin/ruby

def test(&block)
  block.call
end
test { puts "Hello World!"}

This will produce following result:

Hello World!

#!/usr/bin/ruby

BEGIN { 
 # BEGIN block code 
 puts "BEGIN code block"
} 

END { 
 # END block code 
 puts "END code block"
}
 # MAIN block code 
puts "MAIN code block"

BEGIN code block
MAIN code block
END code block