color-words: take an optional regular expression describing words

In some applications, words are not delimited by white space.  To
allow for that, you can specify a regular expression describing
what makes a word with

	git diff --color-words='[A-Za-z0-9]+'

Note that words cannot contain newline characters.

As suggested by Thomas Rast, the words are the exact matches of the
regular expression.

Note that a regular expression beginning with a '^' will match only
a word at the beginning of the hunk, not a word at the beginning of
a line, and is probably not what you want.

This commit contains a quoting fix by Thomas Rast.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt
index 43793d7500..2c1fa4b102 100644
--- a/Documentation/diff-options.txt
+++ b/Documentation/diff-options.txt
@@ -91,8 +91,12 @@ endif::git-format-patch[]
 	Turn off colored diff, even when the configuration file
 	gives the default to color output.
 
---color-words::
+--color-words[=regex]::
 	Show colored word diff, i.e. color words which have changed.
++
+Optionally, you can pass a regular expression that tells Git what the
+words are that you are looking for; The default is to interpret any
+stretch of non-whitespace as a word.
 
 --no-renames::
 	Turn off rename detection, even when the configuration