enumerable.rb in external-0.3.0

- old
+ new

@@ -1,28 +1,65 @@
 require 'enumerator'
 
 module External
+  
+  # An externalized implementation of Enumerable.  External::Enumerable
+  # requires several methods with the following functionality: 
+  # 
+  # each:: iterates over items in self
+  # another::  provide a another instance of self
+  # to_a:: converts self to an Array
+  #
   module Enumerable
-    # def all? # :yield: obj
-    #   not_implemented
-    # end
+    # Flag indicating whether to enumerate (ie collect,
+    # select, etc) into an array or into an instance
+    # of self.  In most cases enumerating to an array
+    # performs better, but enumerating to another
+    # instance of self may be desired for especially
+    # large collections.
+    attr_accessor :enumerate_to_a
     
-    # def any? # :yield: obj
-    #   not_implemented
-    # end
+    def all? # :yield: obj
+      # WARN -- no tests for this in test_array
+      each do |obj|
+        return false unless yield(obj)
+      end
+      true
+    end
     
-    # def collect # :yield: item
-    #   not_implemented
-    # end
+    def any? # :yield: obj
+      # WARN -- no tests for this in test_array
+      each do |obj|
+        return true if yield(obj)
+      end
+      false
+    end
     
+    def collect # :yield: item
+      if block_given?
+        another = enumerate_to_a ? [] : self.another
+        each do |item|
+          another << yield(item)
+        end
+        another
+      else
+        # Not sure if Enumerator works right for large externals...
+        Object::Enumerable::Enumerator.new(self)
+      end
+    end
+    
     # def collect! # :yield: item
     #   not_implemented
     # end
     
-    # def detect(ifnone=nil) # :yield: obj
-    #   not_implemented
-    # end
+    def detect(ifnone=nil) # :yield: obj
+      # WARN -- no tests for this in test_array
+      each do |obj|
+        return obj if yield(obj)
+      end
+      nil
+    end
     
     # def each_cons(n) # :yield:
     #   not_implemented
     # end
     
@@ -36,13 +73,13 @@
           yield(item, i + offset)
         end
       end
     end
     
-    # def entries
-    #   to_a
-    # end
+    def entries
+      to_a
+    end
     
     # def enum_cons(n)
     #   not_implemented
     # end
     
@@ -52,45 +89,53 @@
     
     # def enum_with_index
     #   not_implemented
     # end
     
-    # def find(ifnone=nil, &block) # :yield: obj
-    #   detect(ifnone, &block)
-    # end
+    def find(ifnone=nil, &block) # :yield: obj
+      # WARN -- no tests for this in test_array
+      detect(ifnone, &block)
+    end
     
-    # def find_all # :yield: obj
-    #   not_implemented
-    # end
+    def find_all # :yield: obj
+      another = enumerate_to_a ? [] : self.another
+      each do |item|
+        another << item if yield(item)
+      end
+      another
+    end
     
     # def grep(pattern) # :yield: obj
     #   not_implemented
     # end
     
-    # def include?(obj)
-    #   not_implemented
-    # end
+    def include?(obj)
+      each do |current|
+        return true if current == obj
+      end
+      false
+    end
     
     # def inject(init) # :yield: memo, obj
     #   not_implemented
     # end
     
-    # def map(&block) # :yield: item
-    #   collect(&block)
-    # end
+    def map(&block) # :yield: item
+      collect(&block)
+    end
     
     # def map!(&block) # :yield: item
     #   collect!(&block)
     # end
     
     # def max # :yield: a,b
     #   not_implemented
     # end
     
-    # def member?(obj)
-    #   include?(obj)
-    # end
+    def member?(obj)
+      include?(obj)
+    end
     
     # def min # :yield: a,b
     #   not_implemented
     # end
     
@@ -104,12 +149,12 @@
     
     # def reject! # :yield: item
     #   not_implemented
     # end
     
-    # def select(&block) # :yield: obj
-    #   find_all(&block)
-    # end
+    def select(&block) # :yield: obj
+      find_all(&block)
+    end
     
     # def sort # :yield: a,b
     #   not_implemented
     # end
     
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