[cffi-devel] Re: [Sbcl-devel] encoding of alien c-string once again

[Yaroslav Kavenchuk]

Wow, I'm nappy! :)

Juho Snellman wrote:
> Thanks. There are some issues with this patch.
> 
>   * On non-windows platforms we need to naturalize a string to find
>     out the default external format, and after this change we need to
>     know the default external format to naturalize a string. But
>     that's easy to fix.

Excuse me, I do not have *nix.
May be use :latin-1 to naturalize string with external format?

>   * Also, the patch can't be used stand-alone, since other SBCL
>     internals (e.g. pathname handling) assume that a c-string alien
>     type will be naturalized to a simple-base-string. What's the right
>     thing to do here? Add a new alien-type that does the conversion,
>     and leave c-string as-is, or change to change the behaviour of
>     c-string?

I suggest to replace [simple-]base-string to [simple-]string for all 
pathnames and alien functions calls with c-string.
Patch for win32 is attached.

> 
>   * I'm not sure that the interface is quite right. It seems probable
>     that at one point or another somebody will need to use multiple
>     external formats at once (ebcdic for pathnames and latin-1 for a
>     database connection, or something). So we might need to be able to
>     parametrize the external format to be used when defining the
>     types. As a silly example:

I do not think, that various encodings are necessary for a call of one 
alien function. But even in this case it is possible to use later 
transformation from (* (unsigned 8)) to c-string.

> 
>     (define-alien-routine strdup (c-string :external-format :latin-1)
>        (str (c-string :external-format :utf-8)))

Nice (for future)

>     (Hmm... maybe using a keyword parameter for this is excessive, and
>     an optional would do).

With keyword parameter more readably (IMHO)

Thanks!

-- 
WBR, Yaroslav Kavenchuk.
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: nonascii-pathnames.patch
URL: <https://mailman.common-lisp.net/pipermail/cffi-devel/attachments/20060428/0ca0f496/attachment.ksh>