Tuesday June 05, 2007

As of this evening there are two new features in the builds: Find Usages, and Rename. Let's start with Find Usages. Right click on a symbol and choose "Find Usages" (or use the keyboard shortcut). Let's say I search for the usages of the UserMail class in the Mephisto Rails blogging application (click for full size):

This feature also knows about .rhtml and .erb files - it parses the embedded Ruby and analyzes it. Here's an example where I've searched for the usages of a @comments field in a controller - notice the .rhtml matches:

(Sorry, I know these images might be a bit large on some screens; I should have taken the screenshots at a smaller screen resolution than my usual 1680x1050.)

In the Find usages dialog I can also ask NetBeans to find subtypes of the class rather than usages. Here's an example of what I get if I search for subclasses of the ApplicationController class:

Next, Rename refactoring. Let's say that I want to rename the @comments field in my Rails application controller. I right click on it, choose a new name and hit OK. I then click "Preview", and in the bottom window I get a list of refactoring operations, along with diffs for the currently selected item. I can (and should!) walk through the changes with the Up/Down arrows, and I can unselect any changes that I don't like before I click the Refactor button to apply the changes. Click on the image for full size (I'm showing both the dialog and the results window here; in reality you'd first get the dialog, and when you hit Preview it disappears and you see the bottom window.)

Again, notice how the renaming operation includes changes in .rhtml files. The advantage of this approach over a regular Search/Replace editor operation is that by using parse trees, we have a lot more confidence in the matches. The IDE will not confuse a local variable reference to foo with a method named foo. It does however still have difficulties knowing whether symbols and method names that occur in multiple places refer to say the same method, so at this point it errs on the side of optimism and presents them all as potential uses.

WARNING: This feature is definitely preliminary!! Hopefully the bold red warning in both the Rename and Find Usages dialog makes this really clear. The Refactor button will be disabled and Preview required shortly.

However, this feature should be improving rapidly as I get feedback and implement some more things on my todo-list. Find Usages at least should be quite useful as a navigation tool. If you're going to use the Rename feature, please make a backup of your code first!

(This feature requires the very latest builds - try the Ruby IDE from nbextras.org, or for fuller instructions, see the wiki page. Auto updating from M9 isn't working any more because I'm relying on private APIs that have changed incompatibly.)

P.S. A great big thank you to all of you who have tried the NetBeans Ruby support, and especially to those of you who have provided feedback!