Re: commands to remove commented lines from grep output

[Richard Stallman]

    I sometimes want to see grep matches only for lines of code that are not
    commented out. At least for the simple case of single line comment syntax,
    such as `;' in Lisp and `//' in C++, this is easy to do with `flush-lines'.

As a general feature, it seems useful.

    To make this a little more convenient, I bind a more specific command that
    does this to `;' in *grep* buffers. Another command, bound to `M-;', toggles
    automatic removal of such commented lines.

I am not sure I like that interface for it.  Also, it doesn't work for C.
It could be made to work for C with more code, which would involve
reading the source files and checking whether the lines found are
inside comments.

It seems to me that a new grep option might be a better approach.