supercharged the `edit` command

(1) It now dumps contents of input buffer in an editor when you type 'edit' (or edit -t) inside a non-empty input buffer
(2) it accepts the file:line syntax. This closes #204

When it evals files it now (by default) just replaces the content of eval_string with the content of the file. This is particularly useful if content of file was an incomplete expression as no error is raised instead
the input buffer just awaits more input.

lib/pry/default_commands/introspection.rb

@@ -108,16 +108,16 @@ class Pry
         end
       end
 
-      command "edit", "Invoke the default editor on a file. Type `edit --help` for more info", :keep_retval => true do |*args|
+      command "edit", "Invoke the default editor on a file. Type `edit --help` for more info" do |*args|
         opts = Slop.parse!(args) do |opt|
           opt.banner "Usage: edit [OPTIONS] [FILE]\n" \
-                      "Edit the method FILE in an editor.\n" \
+                      "Edit the method FILE in an editor.\nWhen no file given, opens editor with contents of input buffer and evals after closing." \
-                      "Ensure #{text.bold("Pry.config.editor")} is set to your editor of choice.\n" \
+                      "\nEnsure #{text.bold("Pry.config.editor")} is set to your editor of choice.\n" \
                       "e.g: edit sample.rb"
 
           opt.on :r, "reload", "Eval file content after editing (evals at top level)"
           opt.on :ex, "Open an editor at the line and file that generated the most recent Exception."
-          opt.on :t, "temp", "Open a temporary file in an editor and eval it in current context after closing."
+          opt.on :t, "temp", "Open a temporary file in an editor with contents of input buffer and eval it in current context after closing (same as `edit` with no args)"
           opt.on :p, "play", "Use the pry `play` command to eval the file content after editing."
           opt.on :l, "line", "Specify line number to jump to in file", true, :as => Integer
           opt.on :h, :help, "This message." do
@@ -127,7 +127,6 @@ class Pry
         next if opts.h?
 
         # the context the file will be eval'd in after closing
-        context = TOPLEVEL_BINDING
         should_reload = opts[:r]
 
         if opts.ex?
@@ -142,15 +141,14 @@ class Pry
           line = _pry_.last_exception.line
           next output.puts "Exception has no associated file." if file_name.nil?
           next output.puts "Cannot edit exceptions raised in REPL." if Pry.eval_path == file_name
-        elsif opts.t?
+        elsif opts.t? || arg_string.empty?
           file_name = Tempfile.new(["tmp", ".rb"]).tap(&:close).path
-          line = 0
+          File.open(file_name, "w") { |f| f.puts eval_string } if !eval_string.empty?
+          line = eval_string.lines.count + 1
           should_reload = true
-          context = target
         else
-          next output.puts("Need to specify a file.") if !args.first
+          file_name, line = File.expand_path(args.first).split(/:/)
-          file_name = File.expand_path(args.first)
+          line = line ? line.to_i : opts[:l].to_i
-          line = opts[:l].to_i
         end
 
         invoke_editor(file_name, line)
@@ -162,7 +160,7 @@ class Pry
           end
         elsif should_reload
           silence_warnings do
-            context.eval(File.read(file_name), file_name)
+            eval_string.replace(File.read(file_name))
           end
         end
       end