Make 1.months and friends accurate by introducing a Duration class. #6835 [eventualbuddha]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@5940 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

4 files changed, 94 insertions, 11 deletions

diff --git a/activesupport/lib/active_support/core_ext/date.rb b/activesupport/lib/active_support/core_ext/date.rb
index 239b8c140a..effb749c25 100644
--- a/activesupport/lib/active_support/core_ext/date.rb
+++ b/activesupport/lib/active_support/core_ext/date.rb
@@ -1,6 +1,8 @@
 require 'date'
+require File.dirname(__FILE__) + '/date/calculations'
 require File.dirname(__FILE__) + '/date/conversions'
 
 class Date#:nodoc:
+  include ActiveSupport::CoreExtensions::Date::Calculations
   include ActiveSupport::CoreExtensions::Date::Conversions
 end
diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
new file mode 100644
index 0000000000..f81cd9187e
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -0,0 +1,41 @@
+module ActiveSupport #:nodoc:
+  module CoreExtensions #:nodoc:
+    module Date #:nodoc:
+      # Enables the use of time calculations within Time itself
+      module Calculations
+        def self.included(base) #:nodoc:
+          base.send(:include, ClassMethods)
+          
+          base.send(:alias_method, :plus_without_duration, :+)
+          base.send(:alias_method, :+, :plus_with_duration)
+          
+          base.send(:alias_method, :minus_without_duration, :-)
+          base.send(:alias_method, :-, :minus_with_duration)
+        end
+
+        module ClassMethods
+          def plus_with_duration(other) #:nodoc:
+            if ActiveSupport::Duration === other
+              other.since(self)
+            else
+              plus_without_duration(other)
+            end
+          end
+          
+          def minus_with_duration(other) #:nodoc:
+            self.plus_with_duration(-other)
+          end
+          
+          # Provides precise Date calculations for years, months, and days.  The +options+ parameter takes a hash with 
+          # any of these keys: :months, :days, :years.
+          def advance(options)
+            d = ::Date.new(year + (options.delete(:years) || 0), month, day)
+            d = d >> options.delete(:months) if options[:months]
+            d = d + options.delete(:days) if options[:days]
+            d
+          end
+        end
+      end
+    end
+  end
+end
\ No newline at end of file
diff --git a/activesupport/lib/active_support/core_ext/numeric/time.rb b/activesupport/lib/active_support/core_ext/numeric/time.rb
index 93740046db..aac698f7a8 100644
--- a/activesupport/lib/active_support/core_ext/numeric/time.rb
+++ b/activesupport/lib/active_support/core_ext/numeric/time.rb
@@ -3,51 +3,70 @@ module ActiveSupport #:nodoc:
     module Numeric #:nodoc:
       # Enables the use of time calculations and declarations, like 45.minutes + 2.hours + 4.years.
       #
-      # If you need precise date calculations that doesn't just treat months as 30 days, then have
-      # a look at Time#advance.
+      # These methods use Time#advance for precise date calculations when using from_now, ago, etc. 
+      # as well as adding or subtracting their results from a Time object. For example:
+      #
+      #   # equivalent to Time.now.advance(:months => 1)
+      #   1.month.from_now
+      #
+      #   # equivalent to Time.now.advance(:years => 2)
+      #   2.years.from_now
+      #
+      #   # equivalent to Time.now.advance(:months => 4, :years => 5)
+      #   (4.months + 5.years).from_now
       # 
-      # Some of these methods are approximations, Ruby's core 
+      # While these methods provide precise calculation when used as in the examples above, care
+      # should be taken to note that this is not true if the result of `months', `years', etc is
+      # converted before use:
+      #
+      #   # equivalent to 30.days.to_i.from_now
+      #   1.month.to_i.from_now
+      #
+      #   # equivalent to 365.25.days.to_f.from_now
+      #   1.year.to_f.from_now
+      #
+      # In such cases, Ruby's core 
       # Date[http://stdlib.rubyonrails.org/libdoc/date/rdoc/index.html] and 
       # Time[http://stdlib.rubyonrails.org/libdoc/time/rdoc/index.html] should be used for precision
       # date and time arithmetic
       module Time
         def seconds
-          self
+          ActiveSupport::Duration.new(self, [[:seconds, self]])
         end
         alias :second :seconds
 
         def minutes
-          self * 60
+          ActiveSupport::Duration.new(self * 60, [[:seconds, self * 60]])
         end
         alias :minute :minutes  
         
         def hours
-          self * 60.minutes
+          ActiveSupport::Duration.new(self * 3600, [[:seconds, self * 3600]])
         end
         alias :hour :hours
         
         def days
-          self * 24.hours
+          ActiveSupport::Duration.new(self * 24.hours, [[:days, self]])
         end
         alias :day :days
 
         def weeks
-          self * 7.days
+          ActiveSupport::Duration.new(self * 7.days, [[:days, self * 7]])
         end
         alias :week :weeks
         
         def fortnights
-          self * 2.weeks
+          ActiveSupport::Duration.new(self * 2.weeks, [[:days, self * 14]])
         end
         alias :fortnight :fortnights
         
         def months
-          self * 30.days
+          ActiveSupport::Duration.new(self * 30.days, [[:months, self]])
         end
         alias :month :months
 
         def years
-          (self * 365.25.days).to_i
+          ActiveSupport::Duration.new(self * 365.25.days, [[:years, self]])
         end
         alias :year :years
 
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index cd412368dc..70a4768d13 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -5,6 +5,11 @@ module ActiveSupport #:nodoc:
       module Calculations
         def self.included(base) #:nodoc:
           base.extend(ClassMethods)
+          
+          base.send(:alias_method, :plus_without_duration, :+)
+          base.send(:alias_method, :+, :plus_with_duration)
+          base.send(:alias_method, :minus_without_duration, :-)
+          base.send(:alias_method, :-, :minus_with_duration)
         end
 
         module ClassMethods
@@ -190,6 +195,22 @@ module ActiveSupport #:nodoc:
         def tomorrow
           self.since(1.day)
         end
+        
+        def plus_with_duration(other) #:nodoc:
+          if ActiveSupport::Duration === other
+            other.since(self)
+          else
+            plus_without_duration(other)
+          end
+        end
+
+        def minus_with_duration(other) #:nodoc:
+          if ActiveSupport::Duration === other
+            other.until(self)
+          else
+            minus_without_duration(other)
+          end
+        end
       end
     end
   end