Free Diff tool that is configurable?

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 line difference is exactly this ignore the difference.

Can you please be specific on how to do that?

I give you one more example like System.Exception and Exception both are same for me, so 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

Notepad++ has a compare plugin, which is pretty configurable.

Answer 3

DiffMerge from SourceGear supports this. You'll need to create a Ruleset that matches the files you are merging or edit the default Rule set. In the ruleset add patterns to the Lines to Omit property. See the Ommitted Lines property in the online help for more info.

Answer 4

Best source comparing software that I ever used was BeyondCompare. With it, you could do exactly what you asked for: input a REGEX 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.

Answer 5

If you can't find an existing diff tool that will do what you want you could write your own.

Python has a diff module for writing diff-like tools, which will handle all the complexities of the diffing algorithm for you. They have an example script that will do a file diff in standard unix diff/patch format or side-by-side HTML in 60 lines of code.

The differs in the module let you define 'junk' filters to pre-process lines to remove parts that you do not want included in the diff. these are python functions so you are not limited to regex matches.

edit

I had a quick re-read of the docs and the filters only work for ignoring whole lines or individual chars, which is not what you want. However you can easily pre-process the data you feed into the differ to remove the text you want to ignore.

Answer 6

Not able to find in any few software the feature, though BC and Araxis have this feature, from the Winmerge Wiki it looks like they won't support plugins or any such feature in new future. Too Bad.

Answer 7

If you know how to write JavaScript you can insert the regex in question into the minification portion of the Pretty Diff tool. The tool is entirely free and the code is completely open with inline documentation. If there is a specific feature you would like added to the tool, aside from a personal customization, please let me know and I will add it.

http://mailmarkup.org/prettydiff/prettydiff.html

Answer 8

Try GNU diffutils.

http://www.gnu.org/software/diffutils/manual/html_mono/diff.html#Specified%20Folding

If you are on windows, you can have GNU diff distributed with cygwin from www.cygwin.com.