lib/abstractivator/enumerable_ext.rb in abstractivator-0.0.19 vs lib/abstractivator/enumerable_ext.rb in abstractivator-0.0.20

@@ -45,11 +45,11 @@
 
   def self.proc?(x)
     x.respond_to?(:call)
   end
 
-  def hash_map(get_key, &get_value)
+  def hash_map(get_key=->x{x}, &get_value)
     Hash[self.map{|x| [get_key.(x), get_value ? get_value.(x) : x]}]
   end
 
   def outer_join(right, get_left_key, get_right_key, default_value)
     Enumerable.outer_join(self, right, get_left_key, get_right_key, default_value, default_value)
@@ -88,7 +88,17 @@
   end
 
   def pad_right(n, value=nil, &block)
     block ||= proc { value }
     self + ([n-self.size, 0].max).times.map(&block)
+  end
+
+  def stable_sort(&compare)
+    compare = compare || ->(a, b){a <=> b}
+    xis = self.each_with_index.map{|x, i| [x, i]}
+    sorted = xis.sort do |(a, ai), (b, bi)|
+      primary = compare.call(a, b)
+      primary != 0 ? primary : (ai <=> bi)
+    end
+    sorted.map(&:first)
   end
 end