[PATCH/RFC 0/4] grep: support to match by line number

[Bert Wesarg <bert.wesarg@googlemail.com>]

This series will teach git grep to match at specified line numbers. This is
particular usefull, if you want to see the lines which emits warnings or errors
from a build run (where you only get the line number) and present it nicely to
the user with function and context lines.

The implementation is split-up into preperation patches which are only noise:

Bert Wesarg (4):
  grep: prepare for re-using the space of the regexp member in struct
    grep_pat

    This one moves the regexp member into an union, so that we can later re-use
    the space for the line number information.

  grep: pass current line number down to match_one_pattern

    To actually match at the line number, the function match_one_pattern needs
    to know the current line number, do it with this patch.

  grep: introduce pattern which matches at line number

    This implements the line number matching in the low level grep machinery.

  grep: provide option to match line number

    And lastly, this exposes the new feature by a new -@ option to git grep.

Patch 5 will than support comma separated line ranges as argument to -@, but
this work has not yet started.

 Documentation/git-grep.txt |    6 +++-
 builtin/grep.c             |   10 +++++
 grep.c                     |   87 ++++++++++++++++++++++++++++++--------------
 grep.h                     |   11 ++++--
 4 files changed, 83 insertions(+), 31 deletions(-)

-- 
1.7.5.349.gfeb1a