Line numbering and syntax highlighting

Syntax coloring, and even facing (font changes) should be handled by scanning and manipulating NSMutableAttributedString - you can retain a NSScanner on the text storage and just shift its location around to track what is being edited, should be simple enough.

For line numbering, I would suggest you add a NSTableView to the side of the text view and match its row height to the line height of the text view, do -setAutohidesScrollers:NO on its enclosingScrollView and hide the scrollers. You would then have to use the NSTextView's NSLayoutManager to figure out where the lines break so that your table view will either have blank cells for multiple row lines or varying row height. The advantage to the tableView method is that the line numbers are not part of the text view, so they cannot be hit in editing.

 

I've done a fair amount of work to get a syntax highlighter working, and tried a number of methods. I'll try to outline what has worked best for me as well as other options.

To know when editing has been done, use the textStorageDidProcessEditing: delegate method. You can then call NSTextStorage's editedRange: and changeInLength: methods to intelligently determine what needs to be re-highlighted.

The scanning can be done using an NSScanner; implementing a custom scanner (using NSString's getCharacterAtIndex: or getCharacters:range: methods); or if you want a lot of flexibility, use RegExKitLite. While I haven't done extensive tests, I believe the custom scanner to be the most efficient in most cases.

The actual colouring is best done using NSTextView's layoutManger temporary attribute methods. In my tests these have been significantly faster than using NSTextStorage's permanent attribute methods.

If you want line numbering that just works, this blog entry gives you one.

http://www.noodlesoft.com/blog/2008/10/05/displaying-line-numbers-with-nstextview/

 

And the problem with BBEdit is...?