I am daydreaming that I am a caravan member, driving a herd of 
disobedient camels on the never-ending desert to an oasis called 5.8.0 
when I released new Encode and PerlIO::encoding.  You can get one as 
follows.

Whole:
        Encode
                http://www.dan.co.jp/~dankogai/Encode-1.50.tar.gz
                and CPAN
        PerlIO::encoding
                http://www.dan.co.jp/~dankogai/PerlIO-encoding-0.02.tar.gz
Diff
        Encode
                http://www.dan.co.jp/~dankogai/current-1.50.diff.gz
        PerlIO::encoding
                [ none ]

Diff is pretty big (> 3000 lines) so you should get a whole thing 
instead.

The biggest and the foremost change is the fallback API which is greatly 
enhanced.  NI-XS request of

On Friday, April 19, 2002, at 05:01 , Nick Ing-Simmons wrote:
>   check == 11 - silent fail with $string updated (What Tk wants)

is implemented as FB_QUIET.  see below;

====
Handling Malformed Data
        THE CHECK argument is used as follows.  When you omit it,
        it is identical to CHECK = 0.

        CHECK = Encode::FB_DEFAULT ( == 0)
            If CHECK is 0, (en|de)code will put substitution char-
            acter in place of the malformed character.  for UCM-
            based encodings, <subchar> will be used.  For Unicode,
            \xFFFD is used.  If the data is supposed to be UTF-8,
            an optional lexical warning (category utf8) is given.

        CHECK = Encode::DIE_ON_ERROR (== 1)
            If CHECK is 1, methods will die immediately  with an
            error message.  so when CHECK is set,  you should trap
            the fatal error with eval{} unless you really want to
            let it die on error.

        CHECK = Encode::FB_QUIET
            If CHECK is set to Encode::FB_QUIET, (en|de)code will
            immediately return proccessed part on error, with data
            passed via argument overwritten with unproccessed
            part.  This is handy when have to repeatedly call
            because the source data is chopped in the middle for
            some reasons, such as fixed-width buffer.  Here is a
            sample code that just does this.

              my $data = '';
              while(defined(read $fh, $buffer, 256)){
                # buffer may end in partial character so we append
                $data .= $buffer;
                $utf8 .= decode($encoding, $data, ENCODE::FB_QUIET);
                # $data now contains unprocessed partial character
              }

        CHECK = Encode::FB_WARN
            This is the same as above, except it warns on error.
            Handy when you are debugging the mode above.

        perlqq mode (CHECK = Encode::FB_PERLQQ)
            For encodings that are implemented by Encode::XS,
            CHECK == Encode::FB_PERLQQ turns (en|de)code into
            "perlqq" fallback mode.

            When you decode, '\xXX' will be placed where XX is the
            hex representation of the octet  that could not be
            decoded to utf8.  And when you encode, '\x{xxxx}' will
            be placed where xxxx is the Unicode ID of the charac-
            ter that cannot be found in the character repartoire
            of the encoding.

        The bitmask
            These modes are actually set via bitmask.  here is how
            FB_XX are laid out.  for FB_XX you can import via "use
            Encode qw(:fallbacks)" for generic bitmask constants,
            you can import via
             "use Encode qw(:fallback_all)".

                                 FB_DEFAULT FB_CROAK FB_QUIET FB_WARN  
FB_PERLQQ
             DIE_ON_ERR    0x0001             X
             WARN_ON_ER    0x0002                               X
             RETURN_ON_ERR 0x0004                      X        X
             LEAVE_SRC     0x0008
             PERLQQ        0x0100                                        X

        Unemplemented fallback schemes

        In future you will be able to use a code reference to a
        callback function for the value of CHECK but its API is
        still undecided.
====

Since PerlIO::encoding was uncapable of using this new feature, I have 
updated PerlIO::encoding as well;  Instead of pushing &PL_sv_yes to 
stack, now struct PerlIOEncode has one more member, chk, that is 
initialized with Encode::FB_QUIET.

typedef struct {
     PerlIOBuf base;             /* PerlIOBuf stuff */
     SV *bufsv;                  /* buffer seen by layers above */
     SV *dataSV;                 /* data we have read from layer below */
     SV *enc;                    /* the encoding object */
     SV *chk;                    /* CHECK in Encode methods */
} PerlIOEncode;

Encode now checks the version of PerlIO::encoding and refuse to use an 
obsolete version.  see t/perlio.t on details.

That way PerlIO::encode has no trouble should Encode changes the value 
of FB_QUIET.
As for the partial character problem, I have found it is nearly 
impossible for escape-based encodings to support fixed-length buffer.  
That is well-documented in Encode::PerlIO, a new pod that is added.

As a workaround a new method perlio_ok() is added.  You can check if the 
encoding in question works well with PerlIO.  I know that's not a 
perfect solution but good enough for 5.8.0.  The ultimate solution to 
this problem is for PerlIO to implement line buffer FOR BOTH 
DIRECTIONS.  But that's out and beyond my realm as yet....

And I have no positive or negative proof if the recent Encode works with 
djgpp.  I need more decent environment.  iMac with Virtual PC is okay 
but it is not exactly mine.  I can't use it when my family is awake.  
And I found my thinkpad's C: is (Ugh!) Windoze Me so you can't really 
run vanilla dos.  I want testers on this.  Is Laszlo still working on 
djgpp?  Error logs?

I am exhausted, not just because of 1.50 but also because today happened 
to be the day when my government draws the tax from my bank account.  
Isn't there something like Open Source Tax Deduction Program ?

Dan the Encode Maintainer

1.50 $Date: 2002/04/19 06:13:02 $
! ! Encode.pm Encode.xs Encode/encoding.h
+ t/fallback.pm
   New Fallback API imlemented and documented.  See "perldoc Encode"
   for details
! lib/Encode/JP/JIS7.pm Encode.pm
+ lib/Encode/PerlIO.pod t/perlio.t
   API compliance met.  However, it still does not work unless perlio
   implements line buffer.  See BUGS section in perldoc Encode::PerlIO
   As a sensible workaround, perlio_ok() added to Encode.
! encoding.pm
! lib/Encode/Supported.pod
   Doc fixes from jhi
   Message-Id: <[EMAIL PROTECTED]>
! CN/CN.pm
   Doc fixes from Autrijus
   Message-Id: <[EMAIL PROTECTED]>
! Encode.pm
   perlqq mode documented
! t/JP.t
+ t/jisx0201.euc t/jisx0201.ref
! t/jisx0208.euc t/jisx0208.ref
   t/JP.t tests more rigorously and with other encodings
   t/jisx0201.* added to test JIS7 encodings.  jisx0208 is now PURELY
   in jis0208 (used to contain jisx0201 part).
! Encode/Makefile_PL.e2x
   The resulting Makefile.PL that "enc2xs -M" creates now auto-discovers
   enc2xs and encode.h rather than hard-coded.  This allows the resulting
   module fully CPANizable.
! encoding.pm t/JP.t t/KR.t
   PerlIO detection simplified (checks %INC instead of eval{})
! Encode.xs Encode/encode.h
+ Unicode/Makefile.PL Unicode/Unicode.pm Unicode/Unicode.xs
- lib/Encode/Unicode.pm
   (en|de)code_xs relocated to where it belongs.  Source reindented
   to my taste
! bin/enc2xs
   Additional (U8 *) cast added as suggested by jhi
   Message-Id: <[EMAIL PROTECTED]>

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