Re: Windows file name separators

[ludo@gnu.org (Ludovic Courtès)]

Eli Zaretskii <eliz@gnu.org> skribis:

>> From: ludo@gnu.org (Ludovic Courtès)
>> Date: Mon, 09 Jun 2014 21:42:36 +0200
>> 
>> Eli Zaretskii <eliz@gnu.org> skribis:
>> 
>> > 3. load.test fails:
>> >
>> >      FAIL: load.test: search-path for "foo.scm" yields "dir1/foo.scm"
>> >
>> >    (The messages are misleading: "yields" should be "should yield".)
>> >
>> >    The test fails because:
>> >
>> >     . it compares file names with equal?, which fails when Windows
>> >       file names with mixed forward and backslashes are used, and/or
>> >       when the files differ but for letter case
>> >
>> >     . the expected result uses a relative file name of temp-dir, while
>> >       search-path returns absolute file names
>> >
>> >    Fixed by using "/" to create a file name from its parts in load.c:
>> >
>> > --- libguile/load.c~	2014-02-28 23:01:27 +0200
>> > +++ libguile/load.c	2014-06-08 13:27:24 +0300
>> > @@ -452,11 +452,15 @@ scm_c_string_has_an_ext (char *str, size
>> >    return 0;
>> >  }
>> >  
>> > +#if 0
>> >  #ifdef __MINGW32__
>> >  #define FILE_NAME_SEPARATOR_STRING "\\"
>> >  #else
>> >  #define FILE_NAME_SEPARATOR_STRING "/"
>> >  #endif
>> > +#else
>> > +#define FILE_NAME_SEPARATOR_STRING "/"
>> > +#endif
>> >  
>> >  static int
>> >  is_file_name_separator (SCM c)
>> >
>> >    I don't see any reasons to use the backslashes when constructing
>> >    Windows file names.  Unless someone can tell why using backslashes
>> >    is a good idea, I propose to remove the Windows setting of
>> >    FILE_NAME_SEPARATOR_STRING.
>> 
>> I’m confused: this was added in 4bab7f01 precisely to support MinGW or
>> Windows.  Similarly, boot-9.scm has ‘file-name-separator-string’ and
>> related stuff.  This was the result of the discussion at
>> <http://debbugs.gnu.org/cgi/bugreport.cgi?bug=10474#89>.
>
> Sorry, that's my fault: I didn't explain the problem in enough detail.
>
> There's nothing wrong with the 4bab7f01 commit per se (and you will
> see that its only part that I changed is the definition of
> FILE_NAME_SEPARATOR_STRING for MinGW).  The problem is not in that
> commit, it is elsewhere: in Scheme code, in this case in the test
> suite, that compares file names as simple strings.  Such comparisons
> fail if the file names differ by the style of directory separators:
> one uses forward slashes, the other backslashes, or some mix thereof.
>
> Now, FILE_NAME_SEPARATOR_STRING is used only for constructing file
> names from their parts.  It is not used for testing a particular
> file-name character for being a directory separator.  Therefore, we
> can discard the separate definition of FILE_NAME_SEPARATOR_STRING for
> Windows, and use "/" on all platforms.  This makes the problem of
> comparing file names easier, and in particular lets Guile pass
> load.test.  But it doesn't solve the problem entirely.

OK.  This and your other message clarify things, thanks.

> To solve this problem completely, we need a function that
> canonicalizes a file name wrt directory separators -- converts all
> backslashes to forward slashes.  Does Guile have such a function?

My understanding of your other message is that you now advocate trying
hard to stick to slashes instead of backslashes, in which case a file
name canonicalization function is practically unnecessary, right?

Thanks,
Ludo’.