Re: regexp font-lock highlighting

[Richard Stallman]

    I could avoid painting regexp groups that span multiple lines, but this
    would deprive me from highlighting many interesting things.  I could set
    `font-lock-lines-before' to a higher value but this would slow down
    fontification in general and still not handle all cases.

The current code seems simply to highlight all the \\( and \\)
constructs.  That seems to be reliable, and sufficient for me at least
to match them up.

So I am not sure this ought to be changed further.
Maybe we should leave well enough alone.

                                                              Anyway, I
    believe that I found a solution that does the right thing in most cases
    and will send it to you in the next days.

Could you dscribe in words what it does?