On Fri, 2025-01-10 at 15:52 -0500, James K. Lowden wrote:
> What should I do with the following message?
>
> cobol1: warning: depth line copybook filename
> ----- ---- ----------------------------------------
> --------
> cobol1: warning: 1 1 prog.cob
> cobol1: warning: 2 1 copy1.CPY
> cobol1: warning: 3 1 copy2.CPY
> cobol1: warning: 4 1 copy3.CPY
> cobol1: error: copy3.CPY:1: recursive copybook: 'copy1.CPY' includes
> itself
>
>
> A COBOL copybook is similar to a C include file, but cannot include
> itself, even indirectly. That's the rule. There's no form of
> "include
> guard".
>
> (There's good reason. The Compiler Directing Facility (CDF) supports
> text substitution on the copybook, so that the same input may have
> names with different prefixes, say, in different programs.)
>
> No rule says the compiler must tell the user the route to copybook
> recursion, but I'll bet it's not controversial.
>
> As of now, the warning messages are sent straight to fprintf(3), and
> only the error goes to emit_diagnostic_valist(). Or will, after I
> sort out locations within the CDF.
Assuming that there's some kind of directive in cobol where a directive
on a line in one file triggers the inclusion of another file (rather
like #include directives), there are a couple of ways you could
implement this within the existing GCC diagnostic framework.
(1) error with followup notes
=============================
Something like this pseudo-code:
{
auto_diagnostic_group d;
error (loc_of_include, "recursive copybook: %qs includes itself", name);
for (auto iter : the loop of copybooks)
inform (iter[loc], "%qs includes %qs here", iter[name_a], iter[name_b]);
}
which ought to emit something like:
copy3.CPY:1: error: recursive copybook: 'copy1.CPY' includes itself
(quoted source)
^~~~~~~~~~~~~~~
prog.cob:1: note: 'prog.cob' includes 'copy1.CPY' here
(quoted source)
^~~~~~~~~~~~~~~
copy1.CPY:1: note: 'copy1.CPY' includes 'copy2.CPY' here
(quoted source)
^~~~~~~~~~~~~~~
copy2.CPY:1: note: 'copy2.CPY' includes 'copy3.CPY' here
(quoted source)
^~~~~~~~~~~~~~~
copy3.CPY:1: note: 'copy3.CPY' includes 'copy1.CPY' here
(quoted source)
^~~~~~~~~~~~~~~
...if you see what I mean, showing the directives in their files,
quoting the source to the user. The user's IDE can probably knows how
to deal with this format, and can respond to clicks on the notes to
take the user to the pertinent places in the code.
maybe with a trailing
copy3.CPY:1: note: 'copy1.CPY' was already included by 'prog.cob'
or somesuch.
(2) error with diagnostic path
==============================
GCC diagnostics can have a "diagnostic_path" associated with them. Up
to now, these have always referred to paths of execution through the
code, but it *might* make sense to use this facility here, which would
capture the chain in a structured way in SARIF output. That said, I
looked briefly at doing this, and the existing presentation code makes
so many assumptions that these are "events", and it's also somewhat
fiddlier to implement. Hence I recommend the approach (1) above
instead.
I suppose there's also:
(3) error with text art diagram
===============================
If you wanted to get really fancy, there's text_art::tree_widget for
drawing ASCII/unicode art of hierarchical data structures. But such
diagrams should be used very sparingly, and it's probably a no-no here
for accessibility reasons; although it might look cool I think (1) is
superior here from a UX perspective.
Hope this is helpful
Dave
