There are lot more things improved in Ruby 1.9.2, I am going to discuss about 3 new things I liked which is introduced in Ruby 1.9.x.

Block Variable Scope in Ruby 1.9.x

Block arguments don’t clash with local variables, arguments are always local.
This is a nice fix in Ruby 1.9 .
 
Ruby 1.8
 check_block = 2
check_block
 => 2 

1.upto(5) {|check_block| check_block} 
check_block
 => 5 

Checkout the value of local variable changed to 5, which is clash with the block variable.

Ruby 1.9
check_block = 2
check_block
 => 2 

1.upto(5) {|check_block| check_block} 
check_block
 => 2 

Here the value of check_block is still 2.

New lambda syntax in Ruby 1.9

lambda =->(a, b){a + b}
lambda.(1,3)
=> 4

We can even call the lambda function like

lambda[2,4]
=> 6

It is also possible to give default values for arguments.

lambda =->(a, b = 10){a + b}
lambda.(1)
=> 11

note : Ruby 1.9.2 still supports the older lambda syntax.

New hash Literal

Alternate syntax for Symbol => Object hash notation:

 Ruby 1.8
{:symbol => 10}
=> {:symbol => 10}

Ruby 1.9
{symbol: 10}
=> {:symbol => 10}

I will get back to you soon with some additional new things that was in Ruby 1.9.2 .
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