Re: Question about byte-compiler warning

[Stefan Monnier]

> Create a test file like:

> test.el:
> ========
> (cond
> ((featurep 'xemacs)
>  (defun bar ()
>    (message "bar XEmacs"))
>  (defun foo ()
>    (bar)))
> (t
>  (defun bar ()
>    (message "bar Emacs"))
>  (defun foo ()
>    (bar))))

> (defun foobar ()
>  (interactive)
>  (foo))
> ========


> Now byte-compile the file above.

> The byte-compiler gives the following warning:

>    In end of data:
>    test.el:17:1:Warning: the following functions are not known to be
> defined:
>        bar, foo


> But aren't these functions (bar and foo) defined using cond construct?

> Why does the byte-compiler give this warning?

The byte-compiler only considers as defined a function which is trivially
obviously defined without having to do any kind of analysis.  I.e. it
doesn't look inside conditionals (or even inside `let's) to figure out what
might be defined in there.

A workaround I use sometimes is

   (defalias 'foo
     (if <toto>
         (lambda (bla) bli)
       (lambda (blo) blu)))

When the condition <toto> is used for several functions, this is a bit
inconvenient, tho.


        Stefan