Re: Why does byte-compile-file copy the input file to a different buffer?

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 17 Dec 2023 17:09:28 +0000
> Cc: emacs-devel@gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> > The command uses insert-file-contents to insert the file into the
> > input buffer, and works on that, so that looks very natural to me.
> > I'm not sure what is bothering you in that, or why.
> 
> >From inside the reader, the buffer " *Compiler Input*" is effectively
> anonymous: it gives no clue as to what the actual file or buffer is.

This doesn't appear to be true, since byte-compile-file binds
buffer-file-name to the name of the file whose contents it inserted.
It does that only temporarily, for calling normal-mode, but maybe we
could just do that for the entire duration of the compilation.

> All I want is the name of the real buffer, or failing that, the name of
> the real file.  When the reader sees " *Compiler Input*" does it have to
> assume that byte-compile-current-file is bound and use that?  Even
> recognising " *Compiler Input*-1" in C code is difficult - there're no
> string functions in Emacs which can test that a given string is a prefix
> of another string.  There's string-match, but it only works with a
> regular expression, not a plain string.  By the time I put that sort of
> code into a C routine, it is so bulky, it drowns out the prime purpose
> of the routine.
> 
> It's difficult.

If all you need is to have buffer-file-name set to the file's name, I
think that can be arranged relatively easily.