_ruby topic for unary operator overload instance in Ruby

Unary operation we all know that the expression operator has only one input value. This is common in both C and Java. Today we'll explore the unary operator overload in Ruby.
Unary operators are: +–*! &, in order to avoid confusion with numerical +–, overload unary operators, followed by an @ operator.

1. A simple unary operator overload example:-@ operator
we use the string class as an example. string is not defined by default-operator:

Copy Code code as follows:

1.9.3p125:027 > A = "Hello"

=> "Hello"

1.9.3p125:028 >-A

nomethoderror:undefined method '-@ ' for "Hello": String

From (IRB): 28

From ~/.rvm/rubies/ruby-1.9.3-p125/bin/irb:16:in '

1.9.3p125:029 >

We use the Open class method (open class to refer to) to a object of type string, plus a unary operation:

Copy Code code as follows:

1.9.3p125:029 > Def a.-@;d owncase;end;

1.9.3p125:036 > A
=> "Hello"
1.9.3p125:037 >-A
=> "Hello"
1.9.3p125:038 >

See from the above code that we have added the-this operator to the A object.

2. Other operators: +@, ~,!
again, we use the attributes of the Open class to add a method to the string class:

Copy Code code as follows:

#!/usr/local/ruby/bin/ruby

Class String

def-@

Downcase

End

def +@

UpCase

End

def ~

# do a ROT13 transformation-http://en.wikipedia.org/wiki/rot13

Tr ' a-za-z ', ' n-za-mn-za-m '

End

def To_proc

proc.new {self}

End

def to_a

[Self.reverse]

End

End

str = "Teketa ' s Blog is great"

Puts "-#{str} = #{-str}"

Puts "+#{str} = #{+str}"

Puts "~#{str} = #{~str}"

Puts "#{str}.to_a = #{str.to_a}"

Puts%w{a, B}.map &str

Puts *str

The running result of the above code:

Copy Code code as follows:

-teketa ' s blog is great = Teketa ' s blog is great

+teketa ' s blog is great = Teketa ' s blog is great

~teketa ' s Blog is great = Grxrgn ' F oybt VF terng

Teketa ' s Blog is great.to_a = ["Taerg si golb s ' ateket"]

Teketa ' s Blog is great

Teketa ' s Blog is great

Taerg si golb s ' ateket

We note that the * and & operators are overloaded by To_a and To_proc, and in Ruby, overloading * and & is accomplished by overloading the to_a and To_proc methods.