add delete to list

lib/parfait/list.rb

@@ -44,6 +44,22 @@ module Parfait
       self.set( self.get_length + 1 , value)
     end
 
+    def delete value
+      index = index_of value
+      return false unless index
+      delete_at index
+    end
+
+    def delete_at index
+      # TODO bounds check
+      while(index < self.get_length)
+        set( index , get(index + 1))
+        index = index + 1
+      end
+      set_length( self.get_length - 1)
+      true
+    end
+
     def first
       return nil unless empty?
       get(1)
@@ -86,8 +102,13 @@ module Parfait
     end
 
     def set_length len
-      # TODO check if not shrinking
+      was = self.get_length
-      grow_to len
+      return if was == len
+      if(was < len)
+        grow_to len
+      else
+        shrink_to len
+      end
     end
 
     def grow_to(len)
@@ -97,6 +118,13 @@ module Parfait
       internal_object_grow(len + 1)
     end
 
+    def shrink_to(len)
+      raise "Only positive lenths, #{len}" if len < 0
+      old_length = self.get_length
+      return if old_length <= len
+      internal_object_shrink(len + 1)
+    end
+
     def ==(other)
       # this should call parfait get_class, alas that is not implemented yet
       return false if other.class != self.class

lib/virtual/parfait_adapter.rb

@@ -90,6 +90,13 @@ module Parfait
         old_length = old_length + 1
       end
     end
+    def internal_object_shrink(length)
+      old_length = internal_object_length()
+      while( length < old_length  )
+        @memory.delete_at(old_length)
+        old_length = old_length - 1
+      end
+    end
 
     def to_s
       Sof::Writer.write(self)

test/parfait/test_list.rb

@@ -49,6 +49,19 @@ class TestList < MiniTest::Test
       assert_equal v , @list.get(k)
     end
   end
+  def test_delete_at
+    test_many_get
+    assert @list.delete_at 2
+    assert_equal 2 , @list.get_length
+    assert_equal 2 , @list.index_of( :three )
+  end
+
+  def test_delete
+    test_many_get
+    assert @list.delete :two
+    assert_equal 2 , @list.get_length
+    assert_equal 2 , @list.index_of( :three )
+  end
   def test_index_of
     test_many_get
     assert_equal 2 , @list.index_of( :two )