Re: completion for compilers (cc, gcc...) and -o

["Daniel Shahaf" <d.s@xxxxxxxxxxxxxxxxxx>]

Vincent Lefevre wrote on Thu, 30 Apr 2020 20:17 +00:00:
> On 2020-04-30 18:14:59 +0000, Daniel Shahaf wrote:
> > Vincent Lefevre wrote on Thu, 30 Apr 2020 10:51 +0200:
> > > The -o option is currently handled by
> > > 
> > >   '-o:output file:_files -g "^*.(c|h|cc|C|cxx)(-.)"'
> > > 
> > > I wonder whether .i files (preprocessed files, e.g. for bug reports)
> > > should be excluded too. One can choose such files for output with
> > > "gcc -E", but:
> > >   * in this case, one generally chooses to use the shorter ">" (or a
> > >     pipe) rather than "-o" (gcc -E file.c > file.i);
> > 
> > I don't see how the existence of other ways to create .i files is
> > a reason not to complete .i files after -o.
> 
> I've googled a bit, and most examples with -E and storage in a file
> used the redirection.

You've got your conditional probabilities backwards.  The _a priori_
likelihood that -o should be used to create a .i file is irrelevant to
what should be completed after -o.

> BTW, all examples used the -E first, so perhaps
> accept .i files for -o only when -E is present.
> 
> Note that GCC describes .i files as source files (among other
> extensions of source files).

They're _intermediate_ files; they can be either input or output.  But
they _can_ be output, so we should complete them, shouldn't we?

> > >   * using such files as a source may be more common.
> > 
> > Assuming so arguendo, how does that bear on what the completion function should do?
> > 
> > > Moreover, if I have a C source "myprogram.c", I generally want the
> > > output file (program name) to be "myprogram", or if I need several
> > > versions (e.g. because I test several options), I choose this as a
> > > prefix, e.g. for "myprogram1", "myprogram2", "myprogram-ok", etc.
> > > Now, when "myprogram.c" exists, but not any of the program files,
> > > and I try to complete with
> > > 
> > >   cc -o my[TAB]
> > > 
> > > I'd like the "myprogram" to be taken into account.
> > > 
> > > Currently it seems that if there are no matches without the excluded
> > > pattern, the completion is done on all files, that is, one gets
> > > 
> > >   cc -o myprogram.c
> > > 
> > > This does not make any sense since a .c file should normally not be
> > > an output file. IMHO, instead of that, one should get the filename
> > > without the filename extension:
> > > 
> > >   cc -o myprogram
> > 
> > Offering basenames seems rather like your own personal preference, not
> > something that the completion system should assume everybody does.
> > However, refraining from offering .c files when there are no non-.c
> > files around is probably a good idea.
> 
> Actually, many people do this (for compiling individual source
> files, otherwise for multi-source projects, a Makefile is used
> in general). But it's true that the output file may not be one
> that is the basename of a source file. I think of 2 possibilities
> (perhaps this should be configurable by the user) for -o:
> 
> 1. For the completion, consider all existing non-source items
>    (files and directories) + the basename of each source file.
> 
> 2. Consider all existing non-source items, and if there are no
>    candidates for the completion, then consider the basename of
>    each source file.

I didn't dispute that people run $CC manually; I disputed that we should
complete *.(c|h|...)(:r) [sic] after -o.  On the other hand, I agreed
that we shouldn't offer *.c files after -o even when all files in the
directory are named *.c.  Hope this clarifies my position.

Cheers,

Daniel