On Fri, May 13, 2011 at 7:30 PM, Stefano Lattarini <stefano.lattar...@gmail.com> wrote: > Hello Jack, thanks for the feedback. > > On Friday 13 May 2011, Jack Kelly wrote: >> Comments inline, after some snipping. >> >> On Fri, May 13, 2011 at 6:27 AM, Stefano Lattarini >> <stefano.lattar...@gmail.com> wrote: >> > -snip intro- >> > >> > I thus propose we add an API of this kind. At first, this might be as >> > simple as just defining two proper `AM_V_ECHO' and `AM_Q_ECHO' variables; >> > `AM_V_ECHO' should be `echo' when silent rules are in effect, and `:' >> > when they are not; viceversa for `AM_Q_ECHO'. >> > >> > To give a simplified example of what I'm proposing: >> > >> > $ cat > Makefile.am <<'END' >> > headers: >> > @... [commands defining a shell variable `$headers']; \ >> > $(AM_V_ECHO) "cd somedir && generate-header --flag $$headers"; \ >> > $(AM_Q_ECHO) "GEN headers"; \ >> > cd somedir && generate-header --flag $$headers >> >> If you're just echoing "GEN headers", is there any reason you can't >> use $(AM_V_GEN) here? >> > Well, first of all, assuming that $(AM_V_ECHO) and $(AM_Q_ECHO) aren't > available, using just $(AM_V_GEN) wouldn't be enough to silence the > "cd somedir && generate-header --flag $$headers" message echoed by the > rule above, and this clearly defies the purpose of having silent rules > in the first place. Also in case the generation of headers uses a > timestamp file, say ".headers_timestamp" (which would probably be the > case in a real-world example), the use of $(AM_V_GEN) woul cause the > displaying of a leass appealing and IMHO slightly less clear message > "GEN .headers_timpestamp".
You do have $(AM_V_at), though. I am persuaded by your arguments for the general case. > Also, thinking about more general situations, we might want to display > some trimmed-down versions of $headers instead of the constant string > `headers'; for example, we might want to display the number of headers > that are being generated (an information that is available only to the > shell running the rule, and not to the make process): > > -snip example- Agreed. >> Maybe we should have a more general method of >> declaring silencing variables (like the $(AM_V_GEN), but also the >> others that echo 'CC' and friends. Then users who have unconventional >> setups can silence things without echoing 'GEN' everywhere. >> > If I understand correctly what you're suggesting, then I think the current > implementation already offers what you want; see the documentation for the > 'silent-rules' option at: > > <http://www.gnu.org/software/automake/manual/html_node/Options.html> > > (I know, that is, er, "suboptimally" placed; a patch to fix this is still > pending). > > A relevant excerpt: > > You can add your own variables, so strings of your own choice are shown. > The following snippet shows how you would define your own equivalent of > AM_V_GEN: > pkg_verbose = $(pkg_verbose_$(V)) > pkg_verbose_ = $(pkg_verbose_$(AM_DEFAULT_VERBOSITY)) > pkg_verbose_0 = @echo PKG-GEN $@; > > foo: foo.in > (pkg_verbose)cp $(srcdir)/foo.in $@ Yes. I think it would be nice to make a Makefile.am declaration or m4 macro to generate this, the above was what I was looking for. -- Jack
