Free diff tool that is configurable? [closed]

Question

Is there a diff tool that allows me to write regular expression to remove a line from difference?

Like, see the two lines:

this.Visible = true;
Visible = true;

And can I write an expression such that if the line difference is exactly this ignore the difference.

How do I specifically do that?

I give you one more example. Like System.Exception and Exception both are same for me, I don't want to show them in the diff.

Answer 1

You can do this with KDiff3. See the documentation section on Preprocessor Commands.

Update: I see you have a further request that appears to need a semantic diff program. See Semantic Diff Utilities for some suggestions.

Answer 2

The best source comparing software that I ever used was Beyond Compare. With it, you could do exactly what you asked for: input a regular expression that told the software to ignore certain differences. However, it's not free.

If you really need a free applicative, you can try WinMerge. I'm not very fond of the interface, though.