lib/ludy/array/combos.rb in ludy-0.1.8 vs lib/ludy/array/combos.rb in ludy-0.1.9

@@ -1,23 +1,32 @@
 
-require 'ludy/array/reverse_map'
-require 'ludy/symbol/to_proc'
-require 'ludy/array/foldr'
-
 class Array
-  # for each combos
-  #   [[0,1],[2,3]].combos
-  #   => [[0,2],[0,3],[1,2],[1,3]]
-  def combos
-    result = []
-    radixs = reverse_map(&:size)
-    inject(1){|r, i| r * i.size}.times{ |step|
-      result << foldr(lambda{ |i, r|
-                        radix = radixs[r.size]
-                        r.unshift i[step % radix]
-                        step /= radix unless radix.nil?
-                        r
-                      }, [])
-    }
-    result
+  if RUBY_VERSION < '1.9.0'
+    require 'ludy/array/foldr'
+    require 'ludy/symbol/to_proc' if RUBY_VERSION < '1.9.0'
+    # for each combos
+    #   [[0,1],[2,3]].combos
+    #   => [[0,2],[0,3],[1,2],[1,3]]
+    def combos
+      result = []
+      radixs = reverse.map(&:size)
+      inject(1){|r, i| r * i.size}.times{ |step|
+        result << foldr(lambda{ |i, r|
+                          radix = radixs[r.size]
+                          r.unshift i[step % radix]
+                          step /= radix unless radix.nil?
+                          r
+                        }, [])
+      }
+      result
+    end
+  else
+    require 'ludy/array/tail'
+    # for each combos
+    #   [[0,1],[2,3]].combos
+    #   => [[0,2],[0,3],[1,2],[1,3]]
+    # simply: array.first.product *array.tail
+    def combos
+      first.product(*tail)
+    end
   end
 end