How do I use compilation mode?

[Alan Mackenzie]

Hi, Emacs.

I'd like to use compilation mode.  In particular, I have a log file and
extracted lines like this into a separate buffer from it with grep:

cc-mode.acm 47446:[^2012-01-26: mackenzie]: Enable ">>" as double template 
ender.

I'd like to go to line 47446 in the log file by pressing CR on that line.

The instructions on how to do this are not optimal.  I've basically
tried pushing elements onto the documented variables
compilation-error-regexp-alist\\(-alist\\)? in the form that they're in
those lists for other modes.

In particular, I pushed 'acm onto compilation-error-regexp-alist and

((acm "\\(cc-mode.acm\\) \\([0-9]+\\):\\[\\^[0-9]+-[0-9]+-[0-9?]+:[^]]*\\]:"
    1 2 nil))

onto compilation-error-regexp-alist.  On typing CR in the pertinent
buffer, I get the ironic error message "No error here".

I've tried edebugging through compile.el, and just got lost in the
complexity.

Would somebody please help me out here.

-- 
Alan Mackenzie (Nuremberg, Germany).