Move the Haml::VERSION-generation logic into Haml.version.

lib/haml.rb

@@ -881,6 +881,7 @@ $LOAD_PATH << dir unless $LOAD_PATH.include?(dir)
 module Haml
   # Returns a hash representing the version of Haml.
   # The :major, :minor, and :teeny keys have their respective numbers.
+  # The :string key contains a human-readable string representation of the version.
   def self.version
     return @@version if defined?(@@version)
 
@@ -890,6 +891,8 @@ module Haml
       :minor => numbers[1],
       :teeny => numbers[2]
     }
+    @@version[:string] = [:major, :minor, :teeny].map { |comp| @@version[comp] }.compact.join('.')
+    @@version
   end
 
   # Returns the path of file relative to the Haml root.
@@ -899,7 +902,7 @@ module Haml
 
   # A string representing the version of Haml.
   # A more fine-grained representation is generated by Haml.version.
-  VERSION = [:major, :minor, :teeny].map { |comp| version[comp] }.compact.join('.') unless defined?(Haml::VERSION)
+  VERSION = version[:string] unless defined?(Haml::VERSION)
 
   # This method is called by init.rb,
   # which is run by Rails on startup.