Re: grep.el regexp

[Richard M. Stallman]

    Perhaps what is needed to start with is to ask people to send output
    examples of different kinds of grep.  We could put these example in a
    new file etc/grep.txt similarly to etc/compilation.txt.

That is a good idea.  Please start that file.

    I've collected a few examples in the file attached below.  The section
    `grep ???' contains examples deduced from regexps in `grep-regexp-alist'.
    Could someone recognize what grep produces them?

The first three seem to follow the GNU spec for column numbers
and ranges.  I don't know whether GNU grep can output these,
but in principle it could do so.