为所有格字符串制作轨道变形？

Question

I would like to create a method in additional to the default 'foo'.titlecase that will correctly add "possessiveness" to it.

The string is a user's name (<- just did one right there! )

For example: "sam" is the user <%= user.titlecase.possessive + ' Profile' %> => #Sam's Profile

It just needs to handle edge cases like:

Steelers's Profile ( should be Steelers' Profile) Ross's Profile ( should be Ross' Profile )

Answer 1

I needed this too and so I made the implementation available on github and as a gem on rubygems so you can include it in your project pretty easy.

In rails 3 all you do is

gem "possessive" 

and you will have it.

Answer 2

A minor rewrite of BaroqueBobcat's code, for Shoulda lovers (and lovers of the ternary operator):

Initializer:

module StringExtensions
  def possessive
    self + ('s' == self[-1,1] ? "'" : "'s")
  end
end

class String
  include StringExtensions
end

Shoulda spec:

require File.expand_path(File.dirname(__FILE__) + "/../test_helper")

class StringExtensionsTest < ActiveSupport::TestCase
  context 'String' do
    context '#possessive' do
      should "turn sam into sam's" do
        assert_equal "sam's", "sam".possessive
      end
      should "turn Steelers into Steelers'" do
        assert_equal "Steelers'", "Steelers".possessive
      end
    end
  end
end

Edit: see Rimian's answer to this question, which properly handles "who" and "it".

Answer 3

What you want is pretty trivial to do, given ruby's open classes.

class String
  def possessive
    self + case self[-1,1]#1.8.7 style
    when 's' then "'"
    else "'s"
    end
  end
end


#rspec examples
describe "String#possessive" do
  it "should turn Steelers into Steelers'" do
    "Steelers".possessive.should == "Steelers'"
  end
  it "should turn sam into sam's" do
    "sam".possessive.should == "sam's"
  end
end

You would probably want to put this in a plugin, to keep it separate from your business logic code.

$ script/generate plugin Possessiveate

Then just drop the code to the generated init.rb in the plugin's directory. Pretty much all the other generated files aren't needed, but you might be interested in looking at the default file structure.

Answer 4

I didn't really want to use a Gem so implemented a combination of some answers already here. But then I was woken in the middle of the night by the realisation that these examples are incorrect. What about "who" and "it"? (English is hard!)

module Possessive
  def possessive
    suffix = if self.downcase == 'it'
      "s"
    elsif self.downcase == 'who'
      'se'
    elsif self.end_with?('s')
      "'"
    else
      "'s"
    end
    self + suffix
  end
end

class String
  include Possessive
end

And the specs:

describe Possessive do
  it "has possessive names not ending in s" do
    "james".possessive.should == "james'"
  end

  it "has possessive names not ending in s" do
    "James".possessive.should == "James'"
  end

  it "has possessive names ending in s" do
    "sally".possessive.should == "sally"
  end

  it "has possessive names ending in s" do
    "Sally".possessive.should == "Sally's"
  end

  it "has possessive its" do
    "it".possessive.should == "its"
  end

  it "has possessive Its" do
    "It".possessive.should == "Its"
  end

  it "has possessive who" do
    "who".possessive.should == "whose"
  end

  it "has possessive Who" do
    "Who".possessive.should == "Whose"
  end
end

Note: It's not the most elegant solution. But as Albert Einstein said, elegance is for tailors.

Answer 5

If you think that the condition used in all these answers thus far is incorrect, you can instead check if the word is already pluralized.

So using Jamie Flournoy's solution as an example, you can use self == self.pluralize instead of 's' == self[-1, 1] , and get these results:

"Steelers".possessive # Steelers'
"Ross".possessive # Ross's
"Chris".possessive # Chris' before inflections.rb change, Chris's after

"Ross".pluralize is already "Rosses", as it might be expected. But "Chris".pluralize isn't, so you would have to add inflection.irregular "Chris", "Chrises" to inflections.rb in order for the possessive form to show up properly. And I suppose you may have to continually add irregularities for other uncommon words/names to end up having the right possessive forms.

Again this is if you're under the other belief that it's insufficient to check whether the last letter of a string is s.

Answer 6

This approach takes advantage of ActiveSupport::Inflector in order to know if a string is singular or plural, which is more accurate in case of irregular or uncountable words.

In config/initializers/string.rb :

module StringExtensions
  def possessive
    self + (singularize == self ? "'s" : "'")
  end
end

class String
  include StringExtensions
end