Re: Identify included files

[Matt Wallis]

On 09/06/2020 15:57, Fr. Samuel Springuel wrote:
> > On 9 Jun, 2020, at 5:54 AM, Matt Wallis <m7956@acumen-it.co.uk> wrote:
> >
> > I found https://lists.gnu.org/archive/html/lilypond-user/2020-05/msg00148.html 
> > very interesting.
> > It describes how to get lilypond to print out dependencies. Have you looked 
> > into this?
>
> That’s from the start of this thread and I’m making use of it in the 
> with-deps.ly file (and in parse-only.ly on the GNUmake_dependencies branch).  I 
> don’t use it exactly as it was originally presented in that message because the 
> format wasn’t make-freindly, but ly:source-files is the starting point for 
> generating the list of prerequisites.

Sorry - I should have read more carefully!

> > Be clear about the difference between = and :=. You are using = when := would 
> > work fine.
>
> That’s a good point.  I’m carrying over some bad practices from the original 
> Makefile example in the documentation and should clean that up as much as 
> possible.
>
> > Put everything that moves (!) into a variable. For example, I'd have
> >
> > PDF_DIR := PDF/
> >
> > Include the backslash when you define a directory (as above). This is a habit 
> > I've got into and now rely on. It helps me.
>
> Can you elaborate on this?  Why would this be better than what I’ve got?

Good question. I've been doing this out of habit for so long, I had to 
think hard to remember why! I've come up with two reasons:

1. The trailing slash in foo/ forces it to be a directory. For example, 
even when foo does not exist you can't treat foo/ as a regular file:

    $ cat > foo/
    bash: foo/: Is a directory

2. An accidental extra slash causes no problems, but an accidental 
missing slash changes the meaning:

   foo//bar is the same as foo/bar, but
   foobar is not the same as foo/bar


Matt