Made command sets respect :keep_retval

lib/pry/command_set.rb

@@ -10,7 +10,8 @@ class Pry
   class CommandSet
     class Command < Struct.new(:name, :description, :options, :block)
       def call(context, *args)
-        context.instance_exec(*args, &block)
+        ret = context.instance_exec(*args, &block)
+        ret if options[:keep_retval]
       end
     end
 
@@ -89,7 +90,7 @@ class Pry
     def alias_command(new_name, old_name, desc = nil)
       commands[new_name] = commands[old_name].dup
       commands[new_name].name = new_name
-      commands[new_name].description = desc
+      commands[new_name].description = desc if desc
     end
 
     # Runs a command.

test/test.rb

@@ -801,10 +801,6 @@ describe Pry::CommandSet do
     @set.name.should == :some_name
   end
 
-  it 'should have no commands' do
-    @set.commands.should.be.empty
-  end
-
   it 'should call the block used for the command when it is called' do
     run = false
     @set.command 'foo' do
@@ -911,4 +907,14 @@ describe Pry::CommandSet do
 
     @set.commands['foo'].description.should == 'baz'
   end
+
+  it 'should return nil for commands by default' do
+    @set.command('foo') { 3 }
+    @set.run_command(nil, 'foo').should == nil
+  end
+
+  it 'should be able to keep return values' do
+    @set.command('foo', '', :keep_retval => true) { 3 }
+    @set.run_command(nil, 'foo').should == 3
+  end
 end