show class/module body when show-source invoked with no args

lib/pry/default_commands/introspection.rb

@@ -20,13 +20,26 @@ class Pry
       def process(name)
         if module?(name)
           code_or_doc = process_module
-        else method?
+        elsif method?
           code_or_doc = process_method
+        else
+          code_or_doc = process_alternatives
         end
 
         render_output(code_or_doc, opts)
       end
 
+      def process_alternatives
+        if args.empty? && internal_binding?(target)
+          mod = target_self.is_a?(Module) ? target_self : target_self.class
+          self.module_object = Pry::WrappedModule(mod)
+
+          process_module
+        else
+          process_method
+        end
+      end
+
       def module_start_line(mod, candidate_rank=0)
         if opts.present?(:'base-one')
           1

lib/pry/helpers/command_helpers.rb

@@ -39,13 +39,16 @@ class Pry
         [file, line_num]
       end
 
+      def internal_binding?(target)
+        m = target.eval("__method__").to_s
+        ["__binding__", "__binding_impl__"].include?(m)
+      end
+
       def get_method_or_raise(name, target, opts={}, omit_help=false)
         meth = Pry::Method.from_str(name, target, opts)
 
         if name && !meth
           command_error("The method '#{name}' could not be found.", omit_help)
-        elsif !meth
-          command_error("No method name given, and context is not a method.", omit_help, NonMethodContextError)
         end
 
         (opts[:super] || 0).times do
@@ -56,6 +59,10 @@ class Pry
           end
         end
 
+        if !meth || (!name && internal_binding?(target))
+          command_error("No method name given, and context is not a method.", omit_help, NonMethodContextError)
+        end
+
         set_file_and_dir_locals(meth.source_file)
         meth
       end

test/test_default_commands/test_show_source.rb

@@ -321,6 +321,69 @@ if !mri18_and_no_real_source_location?
           result.should =~ /def instance_eval_method/
         end
       end
+
+      describe "when show-source is invoked without a method or class argument" do
+        before do
+          module Host
+            module M
+              def alpha; end
+              def beta; end
+            end
+
+            module C
+            end
+
+            module D
+              def self.invoked_in_method
+                redirect_pry_io(InputTester.new("show-source", "exit-all"), out = StringIO.new) do
+                  Pry.start(binding)
+                end
+                out.string
+              end
+            end
+          end
+        end
+
+        after do
+          Object.remove_const(:Host)
+        end
+
+        describe "inside a module" do
+          it 'should display module source by default' do
+            redirect_pry_io(InputTester.new("show-source", "exit-all"), out = StringIO.new) do
+              Pry.start(Host::M)
+            end
+
+            out.string.should =~ /module M/
+            out.string.should =~ /def alpha/
+            out.string.should =~ /def beta/
+          end
+
+          it 'should be unable to find module source if no methods defined' do
+            redirect_pry_io(InputTester.new("show-source", "exit-all"), out = StringIO.new) do
+              Pry.start(Host::C)
+            end
+
+            out.string.should.should =~ /Cannot find a definition for/
+          end
+
+          it 'should display method code (rather than class) if Pry started inside method binding' do
+            string = Host::D.invoked_in_method
+            string.should =~ /invoked_in_method/
+            string.should.not =~ /module D/
+          end
+
+          it 'should allow options to be passed' do
+            redirect_pry_io(InputTester.new("show-source -b", "exit-all"), out = StringIO.new) do
+              Pry.start(Host::M)
+            end
+
+            out.string.should =~ /\d:\s*module M/
+            out.string.should =~ /\d:\s*def alpha/
+            out.string.should =~ /\d:\s*def beta/
+          end
+        end
+      end
     end
   end
 end