[RFC/PATCH] attr: map builtin userdiff drivers to well-known extensions

[Jeff King <peff@peff.net>]

We already provide sane hunk-header patterns for specific
languages. However, the user has to manually map common
extensions to use them. It's not that hard to do, but it's
an extra step that the user might not even know is an
option. Let's be nice and do it automatically.

Signed-off-by: Jeff King <peff@peff.net>
---
I tried to think of negative side effects.

The userdiff drivers we have are pretty conservative; they just specify
hunk headers. So if you have a binary file named "foo.c", we still do
the regular binary detection.

If you have any matching attribute line in your own files, it should
override. So:

  foo/* -diff

will still mark foo/bar.c as binary, even with this change.

Can anyone think of other possible side effects?

Also, any other extensions that would go into such a list? I have no
idea what the common extension is for something like pascal or csharp.

 attr.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/attr.c b/attr.c
index da29c8e..5118a14 100644
--- a/attr.c
+++ b/attr.c
@@ -294,6 +294,18 @@ static void free_attr_elem(struct attr_stack *e)
 
 static const char *builtin_attr[] = {
 	"[attr]binary -diff -text",
+	"*.html diff=html",
+	"*.java diff=java",
+	"*.perl diff=perl",
+	"*.pl diff=perl",
+	"*.php diff=php",
+	"*.py diff=python",
+	"*.rb diff=ruby",
+	"*.bib diff=bibtex",
+	"*.tex diff=tex",
+	"*.c diff=cpp",
+	"*.cc diff=cpp",
+	"*.cxx diff=cpp",
 	NULL,
 };
 
-- 
1.7.6.10.g62f04