~michaelforrest/use-case-mapper/trunk

module ActiveSupport #:nodoc:

  module CoreExtensions #:nodoc:

    module String #:nodoc:

      unless '1.9'.respond_to?(:force_encoding)

        # Makes it easier to access parts of a string, such as specific characters and substrings.

        module Access

          # Returns the character at the +position+ treating the string as an array (where 0 is the first character).

          #

          # Examples: 

          #   "hello".at(0)  # => "h"

          #   "hello".at(4)  # => "o"

          #   "hello".at(10) # => nil

          def at(position)

            mb_chars[position, 1].to_s

          end

          

          # Returns the remaining of the string from the +position+ treating the string as an array (where 0 is the first character).

          #

          # Examples: 

          #   "hello".from(0)  # => "hello"

          #   "hello".from(2)  # => "llo"

          #   "hello".from(10) # => nil

          def from(position)

            mb_chars[position..-1].to_s

          end

          

          # Returns the beginning of the string up to the +position+ treating the string as an array (where 0 is the first character).

          #

          # Examples: 

          #   "hello".to(0)  # => "h"

          #   "hello".to(2)  # => "hel"

          #   "hello".to(10) # => "hello"

          def to(position)

            mb_chars[0..position].to_s

          end

 

          # Returns the first character of the string or the first +limit+ characters.

          #

          # Examples: 

          #   "hello".first     # => "h"

          #   "hello".first(2)  # => "he"

          #   "hello".first(10) # => "hello"

          def first(limit = 1)

            if limit == 0

              ''

            elsif limit >= size

              self

            else

              mb_chars[0...limit].to_s

            end

          end

 

          # Returns the last character of the string or the last +limit+ characters.

          #

          # Examples: 

          #   "hello".last     # => "o"

          #   "hello".last(2)  # => "lo"

          #   "hello".last(10) # => "hello"

          def last(limit = 1)

            if limit == 0

              ''

            elsif limit >= size

              self

            else

              mb_chars[(-limit)..-1].to_s

            end

          end

        end

      else

        module Access #:nodoc:

          def at(position)

            self[position]

          end

 

          def from(position)

            self[position..-1]

          end

 

          def to(position)

            self[0..position]

          end

 

          def first(limit = 1)

            if limit == 0

              ''

            elsif limit >= size

              self

            else

              to(limit - 1)

            end

          end

 

          def last(limit = 1)

            if limit == 0

              ''

            elsif limit >= size

              self

            else

              from(-limit)

            end

          end

        end

      end

    end

  end

end