bug#19254: 25.0.50; Special characters not stripped on C/C++ header auto-insert

[Rupert Swarbrick]

The default value of auto-insert-alist is rather unhelpful if you have a
C/C++ header file called something like foo-bar.h because the generated
header guard looks something like

   #ifndef FOO-BAR_H
   #define FOO-BAR_H

   #endif

The hyphen is a break in the CPP identifier, which makes the header
guard not work (GCC, at least, ignores everything past FOO and spits out
a warning). I think that something like the following replacement is
probably better:

  '(("\\.\\([Hh]\\|hh\\|hpp\\)\\'" . "C / C++ header")
    (replace-regexp-in-string
     "[^A-Z0-9]" "_"
     (upcase (file-name-nondirectory buffer-file-name)) t t)
    "#ifndef " str \n
    "#define " str "\n\n"
    _ "\n\n#endif")

This is basically the same as the definition in Emacs master at the
moment, but doesn't explicitly split basename from extension and instead
replaces non-alphanumeric characters with underscores.

Could the default be changed to this or something like it?

Rupert


PS: I'm not including defaults of the build configuration because
    they're pretty irrelevant in this case. I've got a snapshot build
    from master last week and the default auto-insert-alist was last
    changed in 2012.

PPS: If anyone else has been irritated by this, here's a workaround
     until there's a fix in master which makes it to your distribution's
     packages:

       (defvar rjs-c-hdr-replacement
         '(("\\.\\([Hh]\\|hh\\|hpp\\)\\'" . "C / C++ header")
           (replace-regexp-in-string
            "[^A-Z0-9]" "_"
            (upcase (file-name-nondirectory buffer-file-name)) t t)
           "#ifndef " str \n
           "#define " str "\n\n"
           _ "\n\n#endif"))

       (unless (member rjs-c-hdr-replacement auto-insert-alist)
         (setq auto-insert-alist
               (cons rjs-c-hdr-replacement auto-insert-alist)))