From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Sat, 10 Jan 2009 14:08:42 GMT
Subject: Re: [PATCH v2] make diff --color-words customizable
Message-ID: <alpine.DEB.1.00.0901101507590.30769@pacific.mpi-cbg.de>
In-Reply-To: <200901101436.48149.jnareb@gmail.com>

Hi,

On Sat, 10 Jan 2009, Jakub Narebski wrote:

> On Sat, 10 Jan 2009, Johannes Schindelin wrote:
> > On Sat, 10 Jan 2009, Jakub Narebski wrote:
> > > Thomas Rast wrote:
> > > 
> > > > --color-words works (and always worked) by splitting words onto one
> > > > line each, and using the normal line-diff machinery to get a word
> > > > diff. 
> > > 
> > > Cannot we generalize diff machinery / use underlying LCS diff engine
> > > instead of going through line diff?
> > 
> > What do you think we're doing?  libxdiff is pretty hardcoded to newlines.  
> > That's why we're substituting non-word characters with newlines.
> 
> Isn't Meyers algorithm used by libxdiff based on LCS, largest common
> subsequence, and doesn't it generate from the mathematical point of
> view "diff" between two sequences (two arrays) which just happen to
> be lines? It is a bit strange that libxdiff doesn't export its low
> level algorithm...

Umm.

It _is_ Myers' algorithm.  It just so happens that libxdiff hardcodes 
newline to be the separator.

Ciao,
Dscho