Re: [boost] Thought on paths (more Mac information)

From: Darin Adler (darin_at_[hidden])
Date: 2002-01-28 10:37:08

On 1/28/02 7:20 AM, "Ken Hagan" <k.hagan_at_[hidden]> wrote:

> I confess my ignorance of the Mac here. If I don't set the type
> correctly, is my file "usable"? Should well-behaved Mac apps set
> an appropriate type for any files they create?

On pre-OS-X Mac OS: No, it's not usable. Yes, type must be set on files any
program creates. 

In addition, on Mac OS X, well-behaved Macintosh applications use extensions
when creating files, and set a flag that tells the operating system not to
show the extension to the user by default if the user didn't specify the
extension explicitly when naming the file.

http://developer.apple.com/techpubs/macosx/Essentials/AquaHIGuidelines/AHGIn
tro/Filename_Extension_Hiding.html

Beyond that, some well-behaved OS X applications will also set an
appropriate type for optimal behavior when mixed with OS 9 applications
running in the Classic environment.

This is also part of the cultural requirement you are talking about, but
it's not clear if a pathname library needs to deal with this.

> I think you've set the scope too narrowly. It isn't much use being
> able to parse "filenames" if the resulting strings cannot be used
> to create or open the corresponding files on the target platform.
> That means we have to look at things like file-types which are only
> present on some file systems, but which might be compulsory on those
> systems.

That's true, but there's a separate issue on pre-OS-X Mac OS in that a path
name does not uniquely identify a single file or directory when multiple
volumes have the same name.

> There's also a strong argument for a library that can handle *any*
> name that is legal on the target platform, so that it can be used
> to write a backup utility or with a user-specified filename. (What
> could be more infuriating than a program which can't find a file
> even when you type the name in by hand?)

And any library that used path names exclusively would not be able to do
this on pre-OS-X Mac OS.

> To a lesser extent, a platform-neutral library should also generate
> pathnames that follow the accepted conventions of the platform.
> (Look at the discussion of a command line parser, where folk are
> getting worked up over supporting the "usual" syntax on their OS.
> Getting the culture right matters.)

An excellent point.

    -- Darin