implement edit-method -p

lib/pry/default_commands/introspection.rb

@@ -203,6 +203,7 @@ class Pry
           opt.on :m, :methods, "Operate on methods."
           opt.on :n, "no-reload", "Do not automatically reload the method's file after editing."
           opt.on "no-jump", "Do not fast forward editor to first line of method."
+          opt.on :p, :patch, "Instead of editing the method's file, try to edit in a tempfile and apply as a monkey patch."
           opt.on :c, :context, "Select object context to run under.", true do |context|
             target = Pry.binding_for(target.eval(context))
           end
@@ -213,20 +214,42 @@ class Pry
 
         next if opts.help?
 
+        if !Pry.config.editor
+          output.puts "Error: No editor set!"
+          output.puts "Ensure that #{text.bold("Pry.config.editor")} is set to your editor of choice."
+          next
+        end
+
         meth_name = args.shift
-        if (meth = get_method_object(meth_name, target, opts.to_hash(true))).nil?
+        meth_name, target, type = get_method_attributes(meth_name, target, opts.to_hash(true))
+        meth = get_method_object_from_target(meth_name, target, type)
+
+        if meth.nil?
           output.puts "Invalid method name: #{meth_name}."
           next
         end
 
-        next output.puts "Error: No editor set!\nEnsure that #{text.bold("Pry.config.editor")} is set to your editor of choice." if !Pry.config.editor
+        if opts.p? || is_a_dynamically_defined_method?(meth)
+          code, _ = code_and_code_type_for(meth)
+
+          lines = code.lines.to_a
+          if lines[0] =~ /^def [^( \n]+/
+            lines[0] = "def #{meth_name}#{$'}"
+          else
+            next output.puts "Error: Pry can only patch methods created with the `def` keyword."
+          end
+
+          temp_file do |f|
+            f.puts lines.join
+            f.flush
+            invoke_editor(f.path, 0)
+            Pry.new(:input => StringIO.new(File.read(f.path))).rep(meth.owner)
+          end
+          next
+        end
 
         if is_a_c_method?(meth)
           output.puts "Error: Can't edit a C method."
-        elsif is_a_dynamically_defined_method?(meth)
-          output.puts "Error: Can't edit an eval method."
-
-          # editor is invoked here
         else
           file, line = path_line_for(meth)
           set_file_and_dir_locals(file)

lib/pry/helpers/command_helpers.rb

@@ -178,37 +178,43 @@ class Pry
         [doc, code_type]
       end
 
-      def get_method_object(meth_name, target, options)
+      def get_method_object(meth_name, target=nil, options={})
+        get_method_object_from_target(*get_method_attributes(meth_name, target, options)) rescue nil
+      end
+
+      def get_method_attributes(meth_name, target=nil, options={})
         if meth_name
           if meth_name =~ /(\S+)\#(\S+)\Z/
             context, meth_name = $1, $2
             target = Pry.binding_for(target.eval(context))
-            options["instance-methods"] = true
+            type = :instance
-            options[:methods] = false
           elsif meth_name =~ /(\S+)\.(\S+)\Z/
             context, meth_name = $1, $2
             target = Pry.binding_for(target.eval(context))
-            options["instance-methods"] = false
+            type = :singleton
-            options[:methods] = true
+          elsif options["instance_methods"]
+            type = :instance
+          elsif options[:methods]
+            type = :singleton
+          else
+            type = nil
           end
         else
           meth_name = meth_name_from_binding(target)
+          type = nil
         end
+        [meth_name, target, type]
+      end
 
-        if !meth_name
+      def get_method_object_from_target(meth_name, target, type=nil)
-          return nil
+        case type
-        end
+        when :instance
-
-        if options["instance-methods"]
           target.eval("instance_method(:#{meth_name})") rescue nil
-        elsif options[:methods]
+        when :singleton
           target.eval("method(:#{meth_name})") rescue nil
         else
-          begin
+          get_method_object_from_target(meth_name, target, :instance) ||
-            target.eval("instance_method(:#{meth_name})")
+            get_method_object_from_target(meth_name, target, :singleton)
-          rescue
-            target.eval("method(:#{meth_name})") rescue nil
-          end
         end
       end