add Enumerable#drop

mrbgems/mruby-enum-ext/mrblib/enum.rb

+##
+# Enumerable
+#
 module Enumerable
+  ##
+  # call-seq:
+  #    enum.drop(n)               -> array
+  #
+  # Drops first n elements from <i>enum</i>, and returns rest elements
+  # in an array.
+  #
+  #    a = [1, 2, 3, 4, 5, 0]
+  #    a.drop(3)             #=> [4, 5, 0]
+
+  def drop(n)
+    raise TypeError, "expected Integer for 1st argument" unless n.kind_of? Integer
+    raise ArgumentError, "attempt to drop negative size" if n < 0
+
+    ary = []
+    self.each {|e| n == 0 ? ary << e : n -= 1 }
+    ary
+  end
   
 end

mrbgems/mruby-enum-ext/test/enum.rb

+##
+# Enumerable(Ext) Test
+
+assert("Enumrable#drop") do
+  a = [1, 2, 3, 4, 5, 0]
+
+  assert_equal a.drop(3), [4, 5, 0]
+  assert_equal a.drop(6), []
+end
+