edit command now supports -p for methods

lib/pry/commands/edit.rb

@@ -56,15 +56,23 @@ class Pry
       if local_edit?
         # edit of local code, eval'd within pry.
         process_local_edit
-      elsif patch_exception?
+      elsif runtime_patch?
         # patch an exception
-        apply_runtime_patch_to_exception
+        apply_runtime_patch
       else
         # edit of remote code, eval'd at top-level
         process_remote_edit
       end
     end
 
+    def retrieve_code_object
+      !probably_a_file?(args.first) && Pry::CodeObject.lookup(args.first, target, _pry_)
+    end
+
+    def runtime_patch?
+      opts.present?(:patch)
+    end
+
     def retrieve_input_expression
       case opts[:i]
       when Range
@@ -109,11 +117,9 @@ class Pry
     def process_local_edit
       content = initial_temp_file_content
 
-      line = content.lines.count
-      source = Pry::Editor.edit_tempfile_with_content(content, line)
       if local_reload?
         silence_warnings do
-          eval_string.replace(source)
+          eval_string.replace Pry::Editor.edit_tempfile_with_content(content, content.lines.count)
         end
       end
     end
@@ -140,7 +146,7 @@ class Pry
     end
 
     def object_file_and_line
-      if !probably_a_file?(args.first) && code_object = Pry::CodeObject.lookup(args.first, target, _pry_)
+      if code_object = retrieve_code_object
         [code_object.source_file, code_object.source_line]
       else
         # break up into file:line
@@ -179,6 +185,35 @@ class Pry
       state.dynamical_ex_file = source.split("\n")
     end
 
+    def apply_runtime_patch_to_method(method_object)
+      lines = method_object.source.lines.to_a
+      lines[0] = definition_line_for_owner(lines[0], method_object.original_name)
+
+      source = wrap_for_nesting(wrap_for_owner(Pry::Editor.edit_tempfile_with_content(lines), method_object.owner), method_object)
+
+      if method_object.alias?
+        with_method_transaction(method_object.original_name, method_object.owner) do
+          _pry_.evaluate_ruby source
+          Pry.binding_for(method_object.owner).eval("alias #{method_object.name} #{original_name}")
+        end
+      else
+        _pry_.evaluate_ruby source
+      end
+    end
+
+    def apply_runtime_patch
+      if patch_exception?
+        apply_runtime_patch_to_exception
+      else
+        code_object = retrieve_code_object
+        if code_object.is_a?(Pry::Method)
+          apply_runtime_patch_to_method(code_object)
+        else
+          raise NotImplementedError, "Cannot yet patch #{code_object} objects!"
+        end
+      end
+    end
+
     def process_remote_edit
       file_name, line = retrieve_file_and_line
 
@@ -194,6 +229,81 @@ class Pry
         end
       end
     end
+
+
+    # Run some code ensuring that at the end target#meth_name will not have changed.
+    #
+    # When we're redefining aliased methods we will overwrite the method at the
+    # unaliased name (so that super continues to work). By wrapping that code in a
+    # transation we make that not happen, which means that alias_method_chains, etc.
+    # continue to work.
+    #
+    # @param [String] meth_name  The method name before aliasing
+    # @param [Module] target  The owner of the method
+    def with_method_transaction(meth_name, target)
+      target = Pry.binding_for(target)
+      temp_name = "__pry_#{meth_name}__"
+
+      target.eval("alias #{temp_name} #{meth_name}")
+      yield
+      target.eval("alias #{meth_name} #{temp_name}")
+    ensure
+      target.eval("undef #{temp_name}") rescue nil
+    end
+
+    # Update the definition line so that it can be eval'd directly on the Method's
+    # owner instead of from the original context.
+    #
+    # In particular this takes `def self.foo` and turns it into `def foo` so that we
+    # don't end up creating the method on the singleton class of the singleton class
+    # by accident.
+    #
+    # This is necessarily done by String manipulation because we can't find out what
+    # syntax is needed for the argument list by ruby-level introspection.
+    #
+    # @param String   The original definition line. e.g. def self.foo(bar, baz=1)
+    # @return String  The new definition line. e.g. def foo(bar, baz=1)
+    def definition_line_for_owner(line, original_name)
+      if line =~ /^def (?:.*?\.)?#{Regexp.escape(original_name)}(?=[\(\s;]|$)/
+        "def #{original_name}#{$'}"
+      else
+        raise CommandError, "Could not find original `def #{original_name}` line to patch."
+      end
+    end
+
+    # Update the source code so that when it has the right owner when eval'd.
+    #
+    # This (combined with definition_line_for_owner) is backup for the case that
+    # wrap_for_nesting fails, to ensure that the method will stil be defined in
+    # the correct place.
+    #
+    # @param [String] source  The source to wrap
+    # @return [String]
+    def wrap_for_owner(source, owner)
+      Thread.current[:__pry_owner__] = owner
+      source = "Thread.current[:__pry_owner__].class_eval do\n#{source}\nend"
+    end
+
+    # Update the new source code to have the correct Module.nesting.
+    #
+    # This method uses syntactic analysis of the original source file to determine
+    # the new nesting, so that we can tell the difference between:
+    #
+    #   class A; def self.b; end; end
+    #   class << A; def b; end; end
+    #
+    # The resulting code should be evaluated in the TOPLEVEL_BINDING.
+    #
+    # @param [String] source  The source to wrap.
+    # @return [String]
+    def wrap_for_nesting(source, method_object)
+      nesting = Pry::Code.from_file(method_object.source_file).nesting_at(method_object.source_line)
+
+      (nesting + [source] + nesting.map{ "end" } + [""]).join("\n")
+    rescue Pry::Indent::UnparseableNestingError => e
+      source
+    end
+
   end
 
   Pry::Commands.add_command(Pry::Command::Edit)

lib/pry/commands/edit_method.rb

@@ -27,10 +27,6 @@ class Pry
     end
 
     def process
-      if !Pry.config.editor
-        raise CommandError, "No editor set!\nEnsure that #{text.bold("Pry.config.editor")} is set to your editor of choice."
-      end
-
       begin
         @method = method_object
       rescue MethodNotFound => err
@@ -53,25 +49,17 @@ class Pry
 
     def process_patch
       lines = @method.source.lines.to_a
-
       lines[0] = definition_line_for_owner(lines[0])
 
-      temp_file do |f|
-        f.puts lines
-        f.flush
-        f.close(false)
-        Pry::Editor.invoke_editor(f.path, 0, true)
+      source = wrap_for_nesting(wrap_for_owner(Pry::Editor.edit_tempfile_with_content(lines)))
 
-        source = wrap_for_nesting(wrap_for_owner(File.read(f.path)))
-
-        if @method.alias?
-          with_method_transaction(original_name, @method.owner) do
-            _pry_.evaluate_ruby source
-            Pry.binding_for(@method.owner).eval("alias #{@method.name} #{original_name}")
-          end
-        else
+      if @method.alias?
+        with_method_transaction(original_name, @method.owner) do
           _pry_.evaluate_ruby source
+          Pry.binding_for(@method.owner).eval("alias #{@method.name} #{original_name}")
         end
+      else
+        _pry_.evaluate_ruby source
       end
     end