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NAME

       perlebcdic - Considerations for running Perl on EBCDIC platforms

DESCRIPTION

       An exploration of some of the issues facing Perl programmers on EBCDIC based computers.
       We do not cover localization, internationalization, or multi-byte character set issues
       other than some discussion of UTF-8 and UTF-EBCDIC.

       Portions that are still incomplete are marked with XXX.

       Perl used to work on EBCDIC machines, but there are now areas of the code where it
       doesn't.  If you want to use Perl on an EBCDIC machine, please let us know by sending mail
       to perlbug@perl.org

COMMON CHARACTER CODE SETS

   ASCII
       The American Standard Code for Information Interchange (ASCII or US-ASCII) is a set of
       integers running from 0 to 127 (decimal) that imply character interpretation by the
       display and other systems of computers.  The range 0..127 can be covered by setting the
       bits in a 7-bit binary digit, hence the set is sometimes referred to as "7-bit ASCII".
       ASCII was described by the American National Standards Institute document ANSI X3.4-1986.
       It was also described by ISO 646:1991 (with localization for currency symbols).  The full
       ASCII set is given in the table below as the first 128 elements.  Languages that can be
       written adequately with the characters in ASCII include English, Hawaiian, Indonesian,
       Swahili and some Native American languages.

       There are many character sets that extend the range of integers from 0..2**7-1 up to
       2**8-1, or 8 bit bytes (octets if you prefer).  One common one is the ISO 8859-1 character
       set.

   ISO 8859
       The ISO 8859-$n are a collection of character code sets from the International
       Organization for Standardization (ISO), each of which adds characters to the ASCII set
       that are typically found in European languages, many of which are based on the Roman, or
       Latin, alphabet.

   Latin 1 (ISO 8859-1)
       A particular 8-bit extension to ASCII that includes grave and acute accented Latin
       characters.  Languages that can employ ISO 8859-1 include all the languages covered by
       ASCII as well as Afrikaans, Albanian, Basque, Catalan, Danish, Faroese, Finnish,
       Norwegian, Portuguese, Spanish, and Swedish.  Dutch is covered albeit without the ij
       ligature.  French is covered too but without the oe ligature.  German can use ISO 8859-1
       but must do so without German-style quotation marks.  This set is based on Western
       European extensions to ASCII and is commonly encountered in world wide web work.  In IBM
       character code set identification terminology ISO 8859-1 is also known as CCSID 819 (or
       sometimes 0819 or even 00819).

   EBCDIC
       The Extended Binary Coded Decimal Interchange Code refers to a large collection of single-
       and multi-byte coded character sets that are different from ASCII or ISO 8859-1 and are
       all slightly different from each other; they typically run on host computers.  The EBCDIC
       encodings derive from 8-bit byte extensions of Hollerith punched card encodings.  The
       layout on the cards was such that high bits were set for the upper and lower case alphabet
       characters [a-z] and [A-Z], but there were gaps within each Latin alphabet range.

       Some IBM EBCDIC character sets may be known by character code set identification numbers
       (CCSID numbers) or code page numbers.

       Perl can be compiled on platforms that run any of three commonly used EBCDIC character
       sets, listed below.

       The 13 variant characters

       Among IBM EBCDIC character code sets there are 13 characters that are often mapped to
       different integer values.  Those characters are known as the 13 "variant" characters and
       are:

           \ [ ] { } ^ ~ ! # | $ @ `

       When Perl is compiled for a platform, it looks at some of these characters to guess which
       EBCDIC character set the platform uses, and adapts itself accordingly to that platform.
       If the platform uses a character set that is not one of the three Perl knows about, Perl
       will either fail to compile, or mistakenly and silently choose one of the three.  They
       are:

       0037
           Character code set ID 0037 is a mapping of the ASCII plus Latin-1 characters (i.e. ISO
           8859-1) to an EBCDIC set.  0037 is used in North American English locales on the
           OS/400 operating system that runs on AS/400 computers.  CCSID 0037 differs from ISO
           8859-1 in 237 places, in other words they agree on only 19 code point values.

       1047
           Character code set ID 1047 is also a mapping of the ASCII plus Latin-1 characters
           (i.e. ISO 8859-1) to an EBCDIC set.  1047 is used under Unix System Services for
           OS/390 or z/OS, and OpenEdition for VM/ESA.  CCSID 1047 differs from CCSID 0037 in
           eight places.

       POSIX-BC
           The EBCDIC code page in use on Siemens' BS2000 system is distinct from 1047 and 0037.
           It is identified below as the POSIX-BC set.

   Unicode code points versus EBCDIC code points
       In Unicode terminology a code point is the number assigned to a character: for example, in
       EBCDIC the character "A" is usually assigned the number 193.  In Unicode the character "A"
       is assigned the number 65.  This causes a problem with the semantics of the pack/unpack
       "U", which are supposed to pack Unicode code points to characters and back to numbers.
       The problem is: which code points to use for code points less than 256?  (for 256 and over
       there's no problem: Unicode code points are used) In EBCDIC, for the low 256 the EBCDIC
       code points are used.  This means that the equivalences

           pack("U", ord($character)) eq $character
           unpack("U", $character) == ord $character

       will hold.  (If Unicode code points were applied consistently over all the possible code
       points, pack("U",ord("A")) would in EBCDIC equal A with acute or chr(101), and unpack("U",
       "A") would equal 65, or non-breaking space, not 193, or ord "A".)

   Remaining Perl Unicode problems in EBCDIC
       ·   Many of the remaining problems seem to be related to case-insensitive matching

       ·   The extensions Unicode::Collate and Unicode::Normalized are not supported under
           EBCDIC, likewise for the encoding pragma.

   Unicode and UTF
       UTF stands for "Unicode Transformation Format".  UTF-8 is an encoding of Unicode into a
       sequence of 8-bit byte chunks, based on ASCII and Latin-1.  The length of a sequence
       required to represent a Unicode code point depends on the ordinal number of that code
       point, with larger numbers requiring more bytes.  UTF-EBCDIC is like UTF-8, but based on
       EBCDIC.

       You may see the term "invariant" character or code point.  This simply means that the
       character has the same numeric value when encoded as when not.  (Note that this is a very
       different concept from "The 13 variant characters" mentioned above.)  For example, the
       ordinal value of 'A' is 193 in most EBCDIC code pages, and also is 193 when encoded in
       UTF-EBCDIC.  All variant code points occupy at least two bytes when encoded.  In UTF-8,
       the code points corresponding to the lowest 128 ordinal numbers (0 - 127: the ASCII
       characters) are invariant.  In UTF-EBCDIC, there are 160 invariant characters.  (If you
       care, the EBCDIC invariants are those characters which have ASCII equivalents, plus those
       that correspond to the C1 controls (80..9f on ASCII platforms).)

       A string encoded in UTF-EBCDIC may be longer (but never shorter) than one encoded in
       UTF-8.

   Using Encode
       Starting from Perl 5.8 you can use the standard new module Encode to translate from EBCDIC
       to Latin-1 code points.  Encode knows about more EBCDIC character sets than Perl can
       currently be compiled to run on.

          use Encode 'from_to';

          my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );

          # $a is in EBCDIC code points
          from_to($a, $ebcdic{ord '^'}, 'latin1');
          # $a is ISO 8859-1 code points

       and from Latin-1 code points to EBCDIC code points

          use Encode 'from_to';

          my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );

          # $a is ISO 8859-1 code points
          from_to($a, 'latin1', $ebcdic{ord '^'});
          # $a is in EBCDIC code points

       For doing I/O it is suggested that you use the autotranslating features of PerlIO, see
       perluniintro.

       Since version 5.8 Perl uses the new PerlIO I/O library.  This enables you to use different
       encodings per IO channel.  For example you may use

           use Encode;
           open($f, ">:encoding(ascii)", "test.ascii");
           print $f "Hello World!\n";
           open($f, ">:encoding(cp37)", "test.ebcdic");
           print $f "Hello World!\n";
           open($f, ">:encoding(latin1)", "test.latin1");
           print $f "Hello World!\n";
           open($f, ">:encoding(utf8)", "test.utf8");
           print $f "Hello World!\n";

       to get four files containing "Hello World!\n" in ASCII, CP 0037 EBCDIC, ISO 8859-1
       (Latin-1) (in this example identical to ASCII since only ASCII characters were printed),
       and UTF-EBCDIC (in this example identical to normal EBCDIC since only characters that
       don't differ between EBCDIC and UTF-EBCDIC were printed).  See the documentation of
       Encode::PerlIO for details.

       As the PerlIO layer uses raw IO (bytes) internally, all this totally ignores things like
       the type of your filesystem (ASCII or EBCDIC).

SINGLE OCTET TABLES

       The following tables list the ASCII and Latin 1 ordered sets including the subsets: C0
       controls (0..31), ASCII graphics (32..7e), delete (7f), C1 controls (80..9f), and Latin-1
       (a.k.a. ISO 8859-1) (a0..ff).  In the table names of the Latin 1 extensions to ASCII have
       been labelled with character names roughly corresponding to The Unicode Standard, Version
       6.1 albeit with substitutions such as s/LATIN// and s/VULGAR// in all cases, s/CAPITAL
       LETTER// in some cases, and s/SMALL LETTER ([A-Z])/\l$1/ in some other cases.  Controls
       are listed using their Unicode 6.1 abbreviatons.  The differences between the 0037 and
       1047 sets are flagged with **.  The differences between the 1047 and POSIX-BC sets are
       flagged with ##.  All ord() numbers listed are decimal.  If you would rather see this
       table listing octal values, then run the table (that is, the pod source text of this
       document, since this recipe may not work with a pod2_other_format translation) through:

       recipe 0

           perl -ne 'if(/(.{29})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
            -e '{printf("%s%-5.03o%-5.03o%-5.03o%.03o\n",$1,$2,$3,$4,$5)}' \
            perlebcdic.pod

       If you want to retain the UTF-x code points then in script form you might want to write:

       recipe 1

        open(FH,"<perlebcdic.pod") or die "Could not open perlebcdic.pod: $!";
        while (<FH>) {
            if (/(.{29})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/)
            {
                if ($7 ne '' && $9 ne '') {
                    printf(
                       "%s%-5.03o%-5.03o%-5.03o%-5.03o%-3o.%-5o%-3o.%.03o\n",
                                                   $1,$2,$3,$4,$5,$6,$7,$8,$9);
                }
                elsif ($7 ne '') {
                    printf("%s%-5.03o%-5.03o%-5.03o%-5.03o%-3o.%-5o%.03o\n",
                                                  $1,$2,$3,$4,$5,$6,$7,$8);
                }
                else {
                    printf("%s%-5.03o%-5.03o%-5.03o%-5.03o%-5.03o%.03o\n",
                                                       $1,$2,$3,$4,$5,$6,$8);
                }
            }
        }

       If you would rather see this table listing hexadecimal values then run the table through:

       recipe 2

           perl -ne 'if(/(.{29})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
            -e '{printf("%s%-5.02X%-5.02X%-5.02X%.02X\n",$1,$2,$3,$4,$5)}' \
            perlebcdic.pod

       Or, in order to retain the UTF-x code points in hexadecimal:

       recipe 3

        open(FH,"<perlebcdic.pod") or die "Could not open perlebcdic.pod: $!";
        while (<FH>) {
            if (/(.{29})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/)
            {
                if ($7 ne '' && $9 ne '') {
                    printf(
                       "%s%-5.02X%-5.02X%-5.02X%-5.02X%-2X.%-6.02X%02X.%02X\n",
                                                  $1,$2,$3,$4,$5,$6,$7,$8,$9);
                }
                elsif ($7 ne '') {
                    printf("%s%-5.02X%-5.02X%-5.02X%-5.02X%-2X.%-6.02X%02X\n",
                                                     $1,$2,$3,$4,$5,$6,$7,$8);
                }
                else {
                    printf("%s%-5.02X%-5.02X%-5.02X%-5.02X%-5.02X%02X\n",
                                                         $1,$2,$3,$4,$5,$6,$8);
                }
            }
        }

                                 ISO
                                8859-1             POS-
                                CCSID  CCSID CCSID IX-
         chr                     0819   0037 1047  BC  UTF-8  UTF-EBCDIC
        ---------------------------------------------------------------------
        <NUL>                       0    0    0    0    0        0
        <SOH>                       1    1    1    1    1        1
        <STX>                       2    2    2    2    2        2
        <ETX>                       3    3    3    3    3        3
        <EOT>                       4    55   55   55   4        55
        <ENQ>                       5    45   45   45   5        45
        <ACK>                       6    46   46   46   6        46
        <BEL>                       7    47   47   47   7        47
        <BS>                        8    22   22   22   8        22
        <HT>                        9    5    5    5    9        5
        <LF>                        10   37   21   21   10       21  **
        <VT>                        11   11   11   11   11       11
        <FF>                        12   12   12   12   12       12
        <CR>                        13   13   13   13   13       13
        <SO>                        14   14   14   14   14       14
        <SI>                        15   15   15   15   15       15
        <DLE>                       16   16   16   16   16       16
        <DC1>                       17   17   17   17   17       17
        <DC2>                       18   18   18   18   18       18
        <DC3>                       19   19   19   19   19       19
        <DC4>                       20   60   60   60   20       60
        <NAK>                       21   61   61   61   21       61
        <SYN>                       22   50   50   50   22       50
        <ETB>                       23   38   38   38   23       38
        <CAN>                       24   24   24   24   24       24
        <EOM>                       25   25   25   25   25       25
        <SUB>                       26   63   63   63   26       63
        <ESC>                       27   39   39   39   27       39
        <FS>                        28   28   28   28   28       28
        <GS>                        29   29   29   29   29       29
        <RS>                        30   30   30   30   30       30
        <US>                        31   31   31   31   31       31
        <SPACE>                     32   64   64   64   32       64
        !                           33   90   90   90   33       90
        "                           34   127  127  127  34       127
        #                           35   123  123  123  35       123
        $                           36   91   91   91   36       91
        %                           37   108  108  108  37       108
        &                           38   80   80   80   38       80
        '                           39   125  125  125  39       125
        (                           40   77   77   77   40       77
        )                           41   93   93   93   41       93
        *                           42   92   92   92   42       92
        +                           43   78   78   78   43       78
        ,                           44   107  107  107  44       107
        -                           45   96   96   96   45       96
        .                           46   75   75   75   46       75
        /                           47   97   97   97   47       97
        0                           48   240  240  240  48       240
        1                           49   241  241  241  49       241
        2                           50   242  242  242  50       242
        3                           51   243  243  243  51       243
        4                           52   244  244  244  52       244
        5                           53   245  245  245  53       245
        6                           54   246  246  246  54       246
        7                           55   247  247  247  55       247
        8                           56   248  248  248  56       248
        9                           57   249  249  249  57       249
        :                           58   122  122  122  58       122
        ;                           59   94   94   94   59       94
        <                           60   76   76   76   60       76
        =                           61   126  126  126  61       126
        >                           62   110  110  110  62       110
        ?                           63   111  111  111  63       111
        @                           64   124  124  124  64       124
        A                           65   193  193  193  65       193
        B                           66   194  194  194  66       194
        C                           67   195  195  195  67       195
        D                           68   196  196  196  68       196
        E                           69   197  197  197  69       197
        F                           70   198  198  198  70       198
        G                           71   199  199  199  71       199
        H                           72   200  200  200  72       200
        I                           73   201  201  201  73       201
        J                           74   209  209  209  74       209
        K                           75   210  210  210  75       210
        L                           76   211  211  211  76       211
        M                           77   212  212  212  77       212
        N                           78   213  213  213  78       213
        O                           79   214  214  214  79       214
        P                           80   215  215  215  80       215
        Q                           81   216  216  216  81       216
        R                           82   217  217  217  82       217
        S                           83   226  226  226  83       226
        T                           84   227  227  227  84       227
        U                           85   228  228  228  85       228
        V                           86   229  229  229  86       229
        W                           87   230  230  230  87       230
        X                           88   231  231  231  88       231
        Y                           89   232  232  232  89       232
        Z                           90   233  233  233  90       233
        [                           91   186  173  187  91       173  ** ##
        \                           92   224  224  188  92       224  ##
        ]                           93   187  189  189  93       189  **
        ^                           94   176  95   106  94       95   ** ##
        _                           95   109  109  109  95       109
        `                           96   121  121  74   96       121  ##
        a                           97   129  129  129  97       129
        b                           98   130  130  130  98       130
        c                           99   131  131  131  99       131
        d                           100  132  132  132  100      132
        e                           101  133  133  133  101      133
        f                           102  134  134  134  102      134
        g                           103  135  135  135  103      135
        h                           104  136  136  136  104      136
        i                           105  137  137  137  105      137
        j                           106  145  145  145  106      145
        k                           107  146  146  146  107      146
        l                           108  147  147  147  108      147
        m                           109  148  148  148  109      148
        n                           110  149  149  149  110      149
        o                           111  150  150  150  111      150
        p                           112  151  151  151  112      151
        q                           113  152  152  152  113      152
        r                           114  153  153  153  114      153
        s                           115  162  162  162  115      162
        t                           116  163  163  163  116      163
        u                           117  164  164  164  117      164
        v                           118  165  165  165  118      165
        w                           119  166  166  166  119      166
        x                           120  167  167  167  120      167
        y                           121  168  168  168  121      168
        z                           122  169  169  169  122      169
        {                           123  192  192  251  123      192  ##
        |                           124  79   79   79   124      79
        }                           125  208  208  253  125      208  ##
        ~                           126  161  161  255  126      161  ##
        <DEL>                       127  7    7    7    127      7
        <PAD>                       128  32   32   32   194.128  32
        <HOP>                       129  33   33   33   194.129  33
        <BPH>                       130  34   34   34   194.130  34
        <NBH>                       131  35   35   35   194.131  35
        <IND>                       132  36   36   36   194.132  36
        <NEL>                       133  21   37   37   194.133  37   **
        <SSA>                       134  6    6    6    194.134  6
        <ESA>                       135  23   23   23   194.135  23
        <HTS>                       136  40   40   40   194.136  40
        <HTJ>                       137  41   41   41   194.137  41
        <VTS>                       138  42   42   42   194.138  42
        <PLD>                       139  43   43   43   194.139  43
        <PLU>                       140  44   44   44   194.140  44
        <RI>                        141  9    9    9    194.141  9
        <SS2>                       142  10   10   10   194.142  10
        <SS3>                       143  27   27   27   194.143  27
        <DCS>                       144  48   48   48   194.144  48
        <PU1>                       145  49   49   49   194.145  49
        <PU2>                       146  26   26   26   194.146  26
        <STS>                       147  51   51   51   194.147  51
        <CCH>                       148  52   52   52   194.148  52
        <MW>                        149  53   53   53   194.149  53
        <SPA>                       150  54   54   54   194.150  54
        <EPA>                       151  8    8    8    194.151  8
        <SOS>                       152  56   56   56   194.152  56
        <SGC>                       153  57   57   57   194.153  57
        <SCI>                       154  58   58   58   194.154  58
        <CSI>                       155  59   59   59   194.155  59
        <ST>                        156  4    4    4    194.156  4
        <OSC>                       157  20   20   20   194.157  20
        <PM>                        158  62   62   62   194.158  62
        <APC>                       159  255  255  95   194.159  255      ##
        <NON-BREAKING SPACE>        160  65   65   65   194.160  128.65
        <INVERTED "!" >             161  170  170  170  194.161  128.66
        <CENT SIGN>                 162  74   74   176  194.162  128.67   ##
        <POUND SIGN>                163  177  177  177  194.163  128.68
        <CURRENCY SIGN>             164  159  159  159  194.164  128.69
        <YEN SIGN>                  165  178  178  178  194.165  128.70
        <BROKEN BAR>                166  106  106  208  194.166  128.71   ##
        <SECTION SIGN>              167  181  181  181  194.167  128.72
        <DIAERESIS>                 168  189  187  121  194.168  128.73   ** ##
        <COPYRIGHT SIGN>            169  180  180  180  194.169  128.74
        <FEMININE ORDINAL>          170  154  154  154  194.170  128.81
        <LEFT POINTING GUILLEMET>   171  138  138  138  194.171  128.82
        <NOT SIGN>                  172  95   176  186  194.172  128.83   ** ##
        <SOFT HYPHEN>               173  202  202  202  194.173  128.84
        <REGISTERED TRADE MARK>     174  175  175  175  194.174  128.85
        <MACRON>                    175  188  188  161  194.175  128.86   ##
        <DEGREE SIGN>               176  144  144  144  194.176  128.87
        <PLUS-OR-MINUS SIGN>        177  143  143  143  194.177  128.88
        <SUPERSCRIPT TWO>           178  234  234  234  194.178  128.89
        <SUPERSCRIPT THREE>         179  250  250  250  194.179  128.98
        <ACUTE ACCENT>              180  190  190  190  194.180  128.99
        <MICRO SIGN>                181  160  160  160  194.181  128.100
        <PARAGRAPH SIGN>            182  182  182  182  194.182  128.101
        <MIDDLE DOT>                183  179  179  179  194.183  128.102
        <CEDILLA>                   184  157  157  157  194.184  128.103
        <SUPERSCRIPT ONE>           185  218  218  218  194.185  128.104
        <MASC. ORDINAL INDICATOR>   186  155  155  155  194.186  128.105
        <RIGHT POINTING GUILLEMET>  187  139  139  139  194.187  128.106
        <FRACTION ONE QUARTER>      188  183  183  183  194.188  128.112
        <FRACTION ONE HALF>         189  184  184  184  194.189  128.113
        <FRACTION THREE QUARTERS>   190  185  185  185  194.190  128.114
        <INVERTED QUESTION MARK>    191  171  171  171  194.191  128.115
        <A WITH GRAVE>              192  100  100  100  195.128  138.65
        <A WITH ACUTE>              193  101  101  101  195.129  138.66
        <A WITH CIRCUMFLEX>         194  98   98   98   195.130  138.67
        <A WITH TILDE>              195  102  102  102  195.131  138.68
        <A WITH DIAERESIS>          196  99   99   99   195.132  138.69
        <A WITH RING ABOVE>         197  103  103  103  195.133  138.70
        <CAPITAL LIGATURE AE>       198  158  158  158  195.134  138.71
        <C WITH CEDILLA>            199  104  104  104  195.135  138.72
        <E WITH GRAVE>              200  116  116  116  195.136  138.73
        <E WITH ACUTE>              201  113  113  113  195.137  138.74
        <E WITH CIRCUMFLEX>         202  114  114  114  195.138  138.81
        <E WITH DIAERESIS>          203  115  115  115  195.139  138.82
        <I WITH GRAVE>              204  120  120  120  195.140  138.83
        <I WITH ACUTE>              205  117  117  117  195.141  138.84
        <I WITH CIRCUMFLEX>         206  118  118  118  195.142  138.85
        <I WITH DIAERESIS>          207  119  119  119  195.143  138.86
        <CAPITAL LETTER ETH>        208  172  172  172  195.144  138.87
        <N WITH TILDE>              209  105  105  105  195.145  138.88
        <O WITH GRAVE>              210  237  237  237  195.146  138.89
        <O WITH ACUTE>              211  238  238  238  195.147  138.98
        <O WITH CIRCUMFLEX>         212  235  235  235  195.148  138.99
        <O WITH TILDE>              213  239  239  239  195.149  138.100
        <O WITH DIAERESIS>          214  236  236  236  195.150  138.101
        <MULTIPLICATION SIGN>       215  191  191  191  195.151  138.102
        <O WITH STROKE>             216  128  128  128  195.152  138.103
        <U WITH GRAVE>              217  253  253  224  195.153  138.104  ##
        <U WITH ACUTE>              218  254  254  254  195.154  138.105
        <U WITH CIRCUMFLEX>         219  251  251  221  195.155  138.106  ##
        <U WITH DIAERESIS>          220  252  252  252  195.156  138.112
        <Y WITH ACUTE>              221  173  186  173  195.157  138.113  ** ##
        <CAPITAL LETTER THORN>      222  174  174  174  195.158  138.114
        <SMALL LETTER SHARP S>      223  89   89   89   195.159  138.115
        <a WITH GRAVE>              224  68   68   68   195.160  139.65
        <a WITH ACUTE>              225  69   69   69   195.161  139.66
        <a WITH CIRCUMFLEX>         226  66   66   66   195.162  139.67
        <a WITH TILDE>              227  70   70   70   195.163  139.68
        <a WITH DIAERESIS>          228  67   67   67   195.164  139.69
        <a WITH RING ABOVE>         229  71   71   71   195.165  139.70
        <SMALL LIGATURE ae>         230  156  156  156  195.166  139.71
        <c WITH CEDILLA>            231  72   72   72   195.167  139.72
        <e WITH GRAVE>              232  84   84   84   195.168  139.73
        <e WITH ACUTE>              233  81   81   81   195.169  139.74
        <e WITH CIRCUMFLEX>         234  82   82   82   195.170  139.81
        <e WITH DIAERESIS>          235  83   83   83   195.171  139.82
        <i WITH GRAVE>              236  88   88   88   195.172  139.83
        <i WITH ACUTE>              237  85   85   85   195.173  139.84
        <i WITH CIRCUMFLEX>         238  86   86   86   195.174  139.85
        <i WITH DIAERESIS>          239  87   87   87   195.175  139.86
        <SMALL LETTER eth>          240  140  140  140  195.176  139.87
        <n WITH TILDE>              241  73   73   73   195.177  139.88
        <o WITH GRAVE>              242  205  205  205  195.178  139.89
        <o WITH ACUTE>              243  206  206  206  195.179  139.98
        <o WITH CIRCUMFLEX>         244  203  203  203  195.180  139.99
        <o WITH TILDE>              245  207  207  207  195.181  139.100
        <o WITH DIAERESIS>          246  204  204  204  195.182  139.101
        <DIVISION SIGN>             247  225  225  225  195.183  139.102
        <o WITH STROKE>             248  112  112  112  195.184  139.103
        <u WITH GRAVE>              249  221  221  192  195.185  139.104  ##
        <u WITH ACUTE>              250  222  222  222  195.186  139.105
        <u WITH CIRCUMFLEX>         251  219  219  219  195.187  139.106
        <u WITH DIAERESIS>          252  220  220  220  195.188  139.112
        <y WITH ACUTE>              253  141  141  141  195.189  139.113
        <SMALL LETTER thorn>        254  142  142  142  195.190  139.114
        <y WITH DIAERESIS>          255  223  223  223  195.191  139.115

       If you would rather see the above table in CCSID 0037 order rather than ASCII + Latin-1
       order then run the table through:

       recipe 4

        perl \
           -ne 'if(/.{29}\d{1,3}\s{2,4}\d{1,3}\s{2,4}\d{1,3}\s{2,4}\d{1,3}/)'\
            -e '{push(@l,$_)}' \
            -e 'END{print map{$_->[0]}' \
            -e '          sort{$a->[1] <=> $b->[1]}' \
            -e '          map{[$_,substr($_,34,3)]}@l;}' perlebcdic.pod

       If you would rather see it in CCSID 1047 order then change the number 34 in the last line
       to 39, like this:

       recipe 5

        perl \
           -ne 'if(/.{29}\d{1,3}\s{2,4}\d{1,3}\s{2,4}\d{1,3}\s{2,4}\d{1,3}/)'\
           -e '{push(@l,$_)}' \
           -e 'END{print map{$_->[0]}' \
           -e '          sort{$a->[1] <=> $b->[1]}' \
           -e '          map{[$_,substr($_,39,3)]}@l;}' perlebcdic.pod

       If you would rather see it in POSIX-BC order then change the number 39 in the last line to
       44, like this:

       recipe 6

        perl \
           -ne 'if(/.{29}\d{1,3}\s{2,4}\d{1,3}\s{2,4}\d{1,3}\s{2,4}\d{1,3}/)'\
            -e '{push(@l,$_)}' \
            -e 'END{print map{$_->[0]}' \
            -e '          sort{$a->[1] <=> $b->[1]}' \
            -e '          map{[$_,substr($_,44,3)]}@l;}' perlebcdic.pod

IDENTIFYING CHARACTER CODE SETS

       To determine the character set you are running under from perl one could use the return
       value of ord() or chr() to test one or more character values.  For example:

           $is_ascii  = "A" eq chr(65);
           $is_ebcdic = "A" eq chr(193);

       Also, "\t" is a "HORIZONTAL TABULATION" character so that:

           $is_ascii  = ord("\t") == 9;
           $is_ebcdic = ord("\t") == 5;

       To distinguish EBCDIC code pages try looking at one or more of the characters that differ
       between them.  For example:

           $is_ebcdic_37   = "\n" eq chr(37);
           $is_ebcdic_1047 = "\n" eq chr(21);

       Or better still choose a character that is uniquely encoded in any of the code sets, e.g.:

           $is_ascii           = ord('[') == 91;
           $is_ebcdic_37       = ord('[') == 186;
           $is_ebcdic_1047     = ord('[') == 173;
           $is_ebcdic_POSIX_BC = ord('[') == 187;

       However, it would be unwise to write tests such as:

           $is_ascii = "\r" ne chr(13);  #  WRONG
           $is_ascii = "\n" ne chr(10);  #  ILL ADVISED

       Obviously the first of these will fail to distinguish most ASCII platforms from either a
       CCSID 0037, a 1047, or a POSIX-BC EBCDIC platform since "\r" eq chr(13) under all of those
       coded character sets.  But note too that because "\n" is chr(13) and "\r" is chr(10) on
       the Macintosh (which is an ASCII platform) the second $is_ascii test will lead to trouble
       there.

       To determine whether or not perl was built under an EBCDIC code page you can use the
       Config module like so:

           use Config;
           $is_ebcdic = $Config{'ebcdic'} eq 'define';

CONVERSIONS

   "utf8::unicode_to_native()" and "utf8::native_to_unicode()"
       These functions take an input numeric code point in one encoding and return what its
       equivalent value is in the other.

   tr///
       In order to convert a string of characters from one character set to another a simple list
       of numbers, such as in the right columns in the above table, along with perl's tr///
       operator is all that is needed.  The data in the table are in ASCII/Latin1 order, hence
       the EBCDIC columns provide easy-to-use ASCII/Latin1 to EBCDIC operations that are also
       easily reversed.

       For example, to convert ASCII/Latin1 to code page 037 take the output of the second
       numbers column from the output of recipe 2 (modified to add '\' characters), and use it in
       tr/// like so:

           $cp_037 =
           '\x00\x01\x02\x03\x37\x2D\x2E\x2F\x16\x05\x25\x0B\x0C\x0D\x0E\x0F' .
           '\x10\x11\x12\x13\x3C\x3D\x32\x26\x18\x19\x3F\x27\x1C\x1D\x1E\x1F' .
           '\x40\x5A\x7F\x7B\x5B\x6C\x50\x7D\x4D\x5D\x5C\x4E\x6B\x60\x4B\x61' .
           '\xF0\xF1\xF2\xF3\xF4\xF5\xF6\xF7\xF8\xF9\x7A\x5E\x4C\x7E\x6E\x6F' .
           '\x7C\xC1\xC2\xC3\xC4\xC5\xC6\xC7\xC8\xC9\xD1\xD2\xD3\xD4\xD5\xD6' .
           '\xD7\xD8\xD9\xE2\xE3\xE4\xE5\xE6\xE7\xE8\xE9\xBA\xE0\xBB\xB0\x6D' .
           '\x79\x81\x82\x83\x84\x85\x86\x87\x88\x89\x91\x92\x93\x94\x95\x96' .
           '\x97\x98\x99\xA2\xA3\xA4\xA5\xA6\xA7\xA8\xA9\xC0\x4F\xD0\xA1\x07' .
           '\x20\x21\x22\x23\x24\x15\x06\x17\x28\x29\x2A\x2B\x2C\x09\x0A\x1B' .
           '\x30\x31\x1A\x33\x34\x35\x36\x08\x38\x39\x3A\x3B\x04\x14\x3E\xFF' .
           '\x41\xAA\x4A\xB1\x9F\xB2\x6A\xB5\xBD\xB4\x9A\x8A\x5F\xCA\xAF\xBC' .
           '\x90\x8F\xEA\xFA\xBE\xA0\xB6\xB3\x9D\xDA\x9B\x8B\xB7\xB8\xB9\xAB' .
           '\x64\x65\x62\x66\x63\x67\x9E\x68\x74\x71\x72\x73\x78\x75\x76\x77' .
           '\xAC\x69\xED\xEE\xEB\xEF\xEC\xBF\x80\xFD\xFE\xFB\xFC\xAD\xAE\x59' .
           '\x44\x45\x42\x46\x43\x47\x9C\x48\x54\x51\x52\x53\x58\x55\x56\x57' .
           '\x8C\x49\xCD\xCE\xCB\xCF\xCC\xE1\x70\xDD\xDE\xDB\xDC\x8D\x8E\xDF';

           my $ebcdic_string = $ascii_string;
           eval '$ebcdic_string =~ tr/\000-\377/' . $cp_037 . '/';

       To convert from EBCDIC 037 to ASCII just reverse the order of the tr/// arguments like so:

           my $ascii_string = $ebcdic_string;
           eval '$ascii_string =~ tr/' . $cp_037 . '/\000-\377/';

       Similarly one could take the output of the third numbers column from recipe 2 to obtain a
       $cp_1047 table.  The fourth numbers column of the output from recipe 2 could provide a
       $cp_posix_bc table suitable for transcoding as well.

       If you wanted to see the inverse tables, you would first have to sort on the desired
       numbers column as in recipes 4, 5 or 6, then take the output of the first numbers column.

   iconv
       XPG operability often implies the presence of an iconv utility available from the shell or
       from the C library.  Consult your system's documentation for information on iconv.

       On OS/390 or z/OS see the iconv(1) manpage.  One way to invoke the iconv shell utility
       from within perl would be to:

           # OS/390 or z/OS example
           $ascii_data = `echo '$ebcdic_data'| iconv -f IBM-1047 -t ISO8859-1`

       or the inverse map:

           # OS/390 or z/OS example
           $ebcdic_data = `echo '$ascii_data'| iconv -f ISO8859-1 -t IBM-1047`

       For other perl-based conversion options see the Convert::* modules on CPAN.

   C RTL
       The OS/390 and z/OS C run-time libraries provide _atoe() and _etoa() functions.

OPERATOR DIFFERENCES

       The ".." range operator treats certain character ranges with care on EBCDIC platforms.
       For example the following array will have twenty six elements on either an EBCDIC platform
       or an ASCII platform:

           @alphabet = ('A'..'Z');   #  $#alphabet == 25

       The bitwise operators such as & ^ | may return different results when operating on string
       or character data in a perl program running on an EBCDIC platform than when run on an
       ASCII platform.  Here is an example adapted from the one in perlop:

           # EBCDIC-based examples
           print "j p \n" ^ " a h";                      # prints "JAPH\n"
           print "JA" | "  ph\n";                        # prints "japh\n"
           print "JAPH\nJunk" & "\277\277\277\277\277";  # prints "japh\n";
           print 'p N$' ^ " E<H\n";                      # prints "Perl\n";

       An interesting property of the 32 C0 control characters in the ASCII table is that they
       can "literally" be constructed as control characters in perl, e.g. "(chr(0)" eq "\c@")>
       "(chr(1)" eq "\cA")>, and so on.  Perl on EBCDIC platforms has been ported to take "\c@"
       to chr(0) and "\cA" to chr(1), etc. as well, but the thirty three characters that result
       depend on which code page you are using.  The table below uses the standard acronyms for
       the controls.  The POSIX-BC and 1047 sets are identical throughout this range and differ
       from the 0037 set at only one spot (21 decimal).  Note that the "LINE FEED" character may
       be generated by "\cJ" on ASCII platforms but by "\cU" on 1047 or POSIX-BC platforms and
       cannot be generated as a "\c.letter." control character on 0037 platforms.  Note also that
       "\c\" cannot be the final element in a string or regex, as it will absorb the terminator.
       But "\c\X" is a "FILE SEPARATOR" concatenated with X for all X.

        chr   ord   8859-1    0037    1047 && POSIX-BC
        -----------------------------------------------------------------------
        \c?   127   <DEL>       "            "
        \c@     0   <NUL>     <NUL>        <NUL>
        \cA     1   <SOH>     <SOH>        <SOH>
        \cB     2   <STX>     <STX>        <STX>
        \cC     3   <ETX>     <ETX>        <ETX>
        \cD     4   <EOT>     <ST>         <ST>
        \cE     5   <ENQ>     <HT>         <HT>
        \cF     6   <ACK>     <SSA>        <SSA>
        \cG     7   <BEL>     <DEL>        <DEL>
        \cH     8   <BS>      <EPA>        <EPA>
        \cI     9   <HT>      <RI>         <RI>
        \cJ    10   <LF>      <SS2>        <SS2>
        \cK    11   <VT>      <VT>         <VT>
        \cL    12   <FF>      <FF>         <FF>
        \cM    13   <CR>      <CR>         <CR>
        \cN    14   <SO>      <SO>         <SO>
        \cO    15   <SI>      <SI>         <SI>
        \cP    16   <DLE>     <DLE>        <DLE>
        \cQ    17   <DC1>     <DC1>        <DC1>
        \cR    18   <DC2>     <DC2>        <DC2>
        \cS    19   <DC3>     <DC3>        <DC3>
        \cT    20   <DC4>     <OSC>        <OSC>
        \cU    21   <NAK>     <NEL>        <LF>              **
        \cV    22   <SYN>     <BS>         <BS>
        \cW    23   <ETB>     <ESA>        <ESA>
        \cX    24   <CAN>     <CAN>        <CAN>
        \cY    25   <EOM>     <EOM>        <EOM>
        \cZ    26   <SUB>     <PU2>        <PU2>
        \c[    27   <ESC>     <SS3>        <SS3>
        \c\X   28   <FS>X     <FS>X        <FS>X
        \c]    29   <GS>      <GS>         <GS>
        \c^    30   <RS>      <RS>         <RS>
        \c_    31   <US>      <US>         <US>

FUNCTION DIFFERENCES

       chr()   chr() must be given an EBCDIC code number argument to yield a desired character
               return value on an EBCDIC platform.  For example:

                   $CAPITAL_LETTER_A = chr(193);

       ord()   ord() will return EBCDIC code number values on an EBCDIC platform.  For example:

                   $the_number_193 = ord("A");

       pack()  The c and C templates for pack() are dependent upon character set encoding.
               Examples of usage on EBCDIC include:

                   $foo = pack("CCCC",193,194,195,196);
                   # $foo eq "ABCD"
                   $foo = pack("C4",193,194,195,196);
                   # same thing

                   $foo = pack("ccxxcc",193,194,195,196);
                   # $foo eq "AB\0\0CD"

       print() One must be careful with scalars and strings that are passed to print that contain
               ASCII encodings.  One common place for this to occur is in the output of the MIME
               type header for CGI script writing.  For example, many perl programming guides
               recommend something similar to:

                   print "Content-type:\ttext/html\015\012\015\012";
                   # this may be wrong on EBCDIC

               Under the IBM OS/390 USS Web Server or WebSphere on z/OS for example you should
               instead write that as:

                   print "Content-type:\ttext/html\r\n\r\n"; # OK for DGW et al

               That is because the translation from EBCDIC to ASCII is done by the web server in
               this case (such code will not be appropriate for the Macintosh however).  Consult
               your web server's documentation for further details.

       printf()
               The formats that can convert characters to numbers and vice versa will be
               different from their ASCII counterparts when executed on an EBCDIC platform.
               Examples include:

                   printf("%c%c%c",193,194,195);  # prints ABC

       sort()  EBCDIC sort results may differ from ASCII sort results especially for mixed case
               strings.  This is discussed in more detail below.

       sprintf()
               See the discussion of printf() above.  An example of the use of sprintf would be:

                   $CAPITAL_LETTER_A = sprintf("%c",193);

       unpack()
               See the discussion of pack() above.

REGULAR EXPRESSION DIFFERENCES

       As of perl 5.005_03 the letter range regular expressions such as [A-Z] and [a-z] have been
       especially coded to not pick up gap characters.  For example, characters such as o "o WITH
       CIRCUMFLEX" that lie between I and J would not be matched by the regular expression range
       "/[H-K]/".  This works in the other direction, too, if either of the range end points is
       explicitly numeric: "[\x89-\x91]" will match "\x8e", even though "\x89" is "i" and "\x91 "
       is "j", and "\x8e" is a gap character from the alphabetic viewpoint.

       If you do want to match the alphabet gap characters in a single octet regular expression
       try matching the hex or octal code such as "/\313/" on EBCDIC or "/\364/" on ASCII
       platforms to have your regular expression match "o WITH CIRCUMFLEX".

       Another construct to be wary of is the inappropriate use of hex or octal constants in
       regular expressions.  Consider the following set of subs:

           sub is_c0 {
               my $char = substr(shift,0,1);
               $char =~ /[\000-\037]/;
           }

           sub is_print_ascii {
               my $char = substr(shift,0,1);
               $char =~ /[\040-\176]/;
           }

           sub is_delete {
               my $char = substr(shift,0,1);
               $char eq "\177";
           }

           sub is_c1 {
               my $char = substr(shift,0,1);
               $char =~ /[\200-\237]/;
           }

           sub is_latin_1 {
               my $char = substr(shift,0,1);
               $char =~ /[\240-\377]/;
           }

       The above would be adequate if the concern was only with numeric code points.  However,
       the concern may be with characters rather than code points and on an EBCDIC platform it
       may be desirable for constructs such as "if (is_print_ascii("A")) {print "A is a printable
       character\n";}" to print out the expected message.  One way to represent the above
       collection of character classification subs that is capable of working across the four
       coded character sets discussed in this document is as follows:

           sub Is_c0 {
               my $char = substr(shift,0,1);
               if (ord('^')==94)  { # ascii
                   return $char =~ /[\000-\037]/;
               }
               if (ord('^')==176) { # 0037
                   return $char =~ /[\000-\003\067\055-\057\026\005\045\013-\023\074\075\062\046\030\031\077\047\034-\037]/;
               }
               if (ord('^')==95 || ord('^')==106) { # 1047 || posix-bc
                   return $char =~ /[\000-\003\067\055-\057\026\005\025\013-\023\074\075\062\046\030\031\077\047\034-\037]/;
               }
           }

           sub Is_print_ascii {
               my $char = substr(shift,0,1);
               $char =~ /[ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/;
           }

           sub Is_delete {
               my $char = substr(shift,0,1);
               if (ord('^')==94)  { # ascii
                   return $char eq "\177";
               }
               else  {              # ebcdic
                   return $char eq "\007";
               }
           }

           sub Is_c1 {
               my $char = substr(shift,0,1);
               if (ord('^')==94)  { # ascii
                   return $char =~ /[\200-\237]/;
               }
               if (ord('^')==176) { # 0037
                   return $char =~ /[\040-\044\025\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/;
               }
               if (ord('^')==95)  { # 1047
                   return $char =~ /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/;
               }
               if (ord('^')==106) { # posix-bc
                   return $char =~
                     /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\137]/;
               }
           }

           sub Is_latin_1 {
               my $char = substr(shift,0,1);
               if (ord('^')==94)  { # ascii
                   return $char =~ /[\240-\377]/;
               }
               if (ord('^')==176) { # 0037
                   return $char =~
                     /[\101\252\112\261\237\262\152\265\275\264\232\212\137\312\257\274\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\375\376\373\374\255\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\335\336\333\334\215\216\337]/;
               }
               if (ord('^')==95)  { # 1047
                   return $char =~
                     /[\101\252\112\261\237\262\152\265\273\264\232\212\260\312\257\274\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\375\376\373\374\272\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\335\336\333\334\215\216\337]/;
               }
               if (ord('^')==106) { # posix-bc
                   return $char =~
                     /[\101\252\260\261\237\262\320\265\171\264\232\212\272\312\257\241\220\217\352\372\276\240\266\263\235\332\233\213\267\270\271\253\144\145\142\146\143\147\236\150\164\161-\163\170\165-\167\254\151\355\356\353\357\354\277\200\340\376\335\374\255\256\131\104\105\102\106\103\107\234\110\124\121-\123\130\125-\127\214\111\315\316\313\317\314\341\160\300\336\333\334\215\216\337]/;
               }
           }

       Note however that only the "Is_ascii_print()" sub is really independent of coded character
       set.  Another way to write "Is_latin_1()" would be to use the characters in the range
       explicitly:

           sub Is_latin_1 {
               my $char = substr(shift,0,1);
               $char =~ /[ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAA~AeAaAECEEEEeIIIIe‐N~OOOO~OeXOUUUUeYPssaaaa~aeaaaeceeeeeiiiie`n~oooo~oeXouuuueypye]/;
           }

       Although that form may run into trouble in network transit (due to the presence of 8 bit
       characters) or on non ISO-Latin character sets.

SOCKETS

       Most socket programming assumes ASCII character encodings in network byte order.
       Exceptions can include CGI script writing under a host web server where the server may
       take care of translation for you.  Most host web servers convert EBCDIC data to ISO-8859-1
       or Unicode on output.

SORTING

       One big difference between ASCII-based character sets and EBCDIC ones are the relative
       positions of upper and lower case letters and the letters compared to the digits.  If
       sorted on an ASCII-based platform the two-letter abbreviation for a physician comes before
       the two letter abbreviation for drive; that is:

        @sorted = sort(qw(Dr. dr.));  # @sorted holds ('Dr.','dr.') on ASCII,
                                         # but ('dr.','Dr.') on EBCDIC

       The property of lowercase before uppercase letters in EBCDIC is even carried to the Latin
       1 EBCDIC pages such as 0037 and 1047.  An example would be that Ee "E WITH DIAERESIS"
       (203) comes before ee "e WITH DIAERESIS" (235) on an ASCII platform, but the latter (83)
       comes before the former (115) on an EBCDIC platform.  (Astute readers will note that the
       uppercase version of ss "SMALL LETTER SHARP S" is simply "SS" and that the upper case
       version of ye "y WITH DIAERESIS" is not in the 0..255 range but it is at U+x0178 in
       Unicode, or "\x{178}" in a Unicode enabled Perl).

       The sort order will cause differences between results obtained on ASCII platforms versus
       EBCDIC platforms.  What follows are some suggestions on how to deal with these
       differences.

   Ignore ASCII vs. EBCDIC sort differences.
       This is the least computationally expensive strategy.  It may require some user education.

   MONO CASE then sort data.
       In order to minimize the expense of mono casing mixed-case text, try to "tr///" towards
       the character set case most employed within the data.  If the data are primarily UPPERCASE
       non Latin 1 then apply tr/[a-z]/[A-Z]/ then sort().  If the data are primarily lowercase
       non Latin 1 then apply tr/[A-Z]/[a-z]/ before sorting.  If the data are primarily
       UPPERCASE and include Latin-1 characters then apply:

          tr/[a-z]/[A-Z]/;
          tr/[aaaa~aeaaaeceeeeeiiiie`n~oooo~oeouuuueyp]/[AAAA~AeAaAECEEEEeIIIIe‐N~OOOO~OeOUUUUeYP/;
          s/ss/SS/g;

       then sort().  Do note however that such Latin-1 manipulation does not address the ye "y
       WITH DIAERESIS" character that will remain at code point 255 on ASCII platforms, but 223
       on most EBCDIC platforms where it will sort to a place less than the EBCDIC numerals.
       With a Unicode-enabled Perl you might try:

           tr/^?/\x{178}/;

       The strategy of mono casing data before sorting does not preserve the case of the data and
       may not be acceptable for that reason.

   Convert, sort data, then re convert.
       This is the most expensive proposition that does not employ a network connection.

   Perform sorting on one type of platform only.
       This strategy can employ a network connection.  As such it would be computationally
       expensive.

TRANSFORMATION FORMATS

       There are a variety of ways of transforming data with an intra character set mapping that
       serve a variety of purposes.  Sorting was discussed in the previous section and a few of
       the other more popular mapping techniques are discussed next.

   URL decoding and encoding
       Note that some URLs have hexadecimal ASCII code points in them in an attempt to overcome
       character or protocol limitation issues.  For example the tilde character is not on every
       keyboard hence a URL of the form:

           http://www.pvhp.com/~pvhp/

       may also be expressed as either of:

           http://www.pvhp.com/%7Epvhp/

           http://www.pvhp.com/%7epvhp/

       where 7E is the hexadecimal ASCII code point for '~'.  Here is an example of decoding such
       a URL under CCSID 1047:

           $url = 'http://www.pvhp.com/%7Epvhp/';
           # this array assumes code page 1047
           my @a2e_1047 = (
                 0,  1,  2,  3, 55, 45, 46, 47, 22,  5, 21, 11, 12, 13, 14, 15,
                16, 17, 18, 19, 60, 61, 50, 38, 24, 25, 63, 39, 28, 29, 30, 31,
                64, 90,127,123, 91,108, 80,125, 77, 93, 92, 78,107, 96, 75, 97,
               240,241,242,243,244,245,246,247,248,249,122, 94, 76,126,110,111,
               124,193,194,195,196,197,198,199,200,201,209,210,211,212,213,214,
               215,216,217,226,227,228,229,230,231,232,233,173,224,189, 95,109,
               121,129,130,131,132,133,134,135,136,137,145,146,147,148,149,150,
               151,152,153,162,163,164,165,166,167,168,169,192, 79,208,161,  7,
                32, 33, 34, 35, 36, 37,  6, 23, 40, 41, 42, 43, 44,  9, 10, 27,
                48, 49, 26, 51, 52, 53, 54,  8, 56, 57, 58, 59,  4, 20, 62,255,
                65,170, 74,177,159,178,106,181,187,180,154,138,176,202,175,188,
               144,143,234,250,190,160,182,179,157,218,155,139,183,184,185,171,
               100,101, 98,102, 99,103,158,104,116,113,114,115,120,117,118,119,
               172,105,237,238,235,239,236,191,128,253,254,251,252,186,174, 89,
                68, 69, 66, 70, 67, 71,156, 72, 84, 81, 82, 83, 88, 85, 86, 87,
               140, 73,205,206,203,207,204,225,112,221,222,219,220,141,142,223
           );
           $url =~ s/%([0-9a-fA-F]{2})/pack("c",$a2e_1047[hex($1)])/ge;

       Conversely, here is a partial solution for the task of encoding such a URL under the 1047
       code page:

           $url = 'http://www.pvhp.com/~pvhp/';
           # this array assumes code page 1047
           my @e2a_1047 = (
                 0,  1,  2,  3,156,  9,134,127,151,141,142, 11, 12, 13, 14, 15,
                16, 17, 18, 19,157, 10,  8,135, 24, 25,146,143, 28, 29, 30, 31,
               128,129,130,131,132,133, 23, 27,136,137,138,139,140,  5,  6,  7,
               144,145, 22,147,148,149,150,  4,152,153,154,155, 20, 21,158, 26,
                32,160,226,228,224,225,227,229,231,241,162, 46, 60, 40, 43,124,
                38,233,234,235,232,237,238,239,236,223, 33, 36, 42, 41, 59, 94,
                45, 47,194,196,192,193,195,197,199,209,166, 44, 37, 95, 62, 63,
               248,201,202,203,200,205,206,207,204, 96, 58, 35, 64, 39, 61, 34,
               216, 97, 98, 99,100,101,102,103,104,105,171,187,240,253,254,177,
               176,106,107,108,109,110,111,112,113,114,170,186,230,184,198,164,
               181,126,115,116,117,118,119,120,121,122,161,191,208, 91,222,174,
               172,163,165,183,169,167,182,188,189,190,221,168,175, 93,180,215,
               123, 65, 66, 67, 68, 69, 70, 71, 72, 73,173,244,246,242,243,245,
               125, 74, 75, 76, 77, 78, 79, 80, 81, 82,185,251,252,249,250,255,
                92,247, 83, 84, 85, 86, 87, 88, 89, 90,178,212,214,210,211,213,
                48, 49, 50, 51, 52, 53, 54, 55, 56, 57,179,219,220,217,218,159
           );
           # The following regular expression does not address the
           # mappings for: ('.' => '%2E', '/' => '%2F', ':' => '%3A')
           $url =~ s/([\t "#%&\(\),;<=>\?\@\[\\\]^`{|}~])/sprintf("%%%02X",$e2a_1047[ord($1)])/ge;

       where a more complete solution would split the URL into components and apply a full s///
       substitution only to the appropriate parts.

       In the remaining examples a @e2a or @a2e array may be employed but the assignment will not
       be shown explicitly.  For code page 1047 you could use the @a2e_1047 or @e2a_1047 arrays
       just shown.

   uu encoding and decoding
       The "u" template to pack() or unpack() will render EBCDIC data in EBCDIC characters
       equivalent to their ASCII counterparts.  For example, the following will print "Yes
       indeed\n" on either an ASCII or EBCDIC computer:

           $all_byte_chrs = '';
           for (0..255) { $all_byte_chrs .= chr($_); }
           $uuencode_byte_chrs = pack('u', $all_byte_chrs);
           ($uu = <<'ENDOFHEREDOC') =~ s/^\s*//gm;
           M``$"`P0%!@<("0H+#`T.#Q`1$A,4%187&!D:&QP='A\@(2(C)"4F)R@I*BLL
           M+2XO,#$R,S0U-C<X.3H[/#T^/T!!0D-$149'2$E*2TQ-3D]045)35%565UA9
           M6EM<75Y?8&%B8V1E9F=H:6IK;&UN;W!Q<G-T=79W>'EZ>WQ]?G^`@8*#A(6&
           MAXB)BHN,C8Z/D)&2DY25EI>8F9J;G)V>GZ"AHJ.DI::GJ*FJJZRMKJ^PL;*S
           MM+6VM[BYNKN\O;Z_P,'"P\3%QL?(R<K+S,W.S]#1TM/4U=;7V-G:V]S=WM_@
           ?X>+CY.7FY^CIZNOL[>[O\/'R\_3U]O?X^?K[_/W^_P``
           ENDOFHEREDOC
           if ($uuencode_byte_chrs eq $uu) {
               print "Yes ";
           }
           $uudecode_byte_chrs = unpack('u', $uuencode_byte_chrs);
           if ($uudecode_byte_chrs eq $all_byte_chrs) {
               print "indeed\n";
           }

       Here is a very spartan uudecoder that will work on EBCDIC provided that the @e2a array is
       filled in appropriately:

           #!/usr/local/bin/perl
           @e2a = ( # this must be filled in
                  );
           $_ = <> until ($mode,$file) = /^begin\s*(\d*)\s*(\S*)/;
           open(OUT, "> $file") if $file ne "";
           while(<>) {
               last if /^end/;
               next if /[a-z]/;
               next unless int(((($e2a[ord()] - 32 ) & 077) + 2) / 3) ==
                   int(length() / 4);
               print OUT unpack("u", $_);
           }
           close(OUT);
           chmod oct($mode), $file;

   Quoted-Printable encoding and decoding
       On ASCII-encoded platforms it is possible to strip characters outside of the printable set
       using:

           # This QP encoder works on ASCII only
           $qp_string =~ s/([=\x00-\x1F\x80-\xFF])/sprintf("=%02X",ord($1))/ge;

       Whereas a QP encoder that works on both ASCII and EBCDIC platforms would look somewhat
       like the following (where the EBCDIC branch @e2a array is omitted for brevity):

           if (ord('A') == 65) {    # ASCII
               $delete = "\x7F";    # ASCII
               @e2a = (0 .. 255)    # ASCII to ASCII identity map
           }
           else {                   # EBCDIC
               $delete = "\x07";    # EBCDIC
               @e2a =               # EBCDIC to ASCII map (as shown above)
           }
           $qp_string =~
             s/([^ !"\#\$%&'()*+,\-.\/0-9:;<>?\@A-Z[\\\]^_`a-z{|}~$delete])/sprintf("=%02X",$e2a[ord($1)])/ge;

       (although in production code the substitutions might be done in the EBCDIC branch with the
       @e2a array and separately in the ASCII branch without the expense of the identity map).

       Such QP strings can be decoded with:

           # This QP decoder is limited to ASCII only
           $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr hex $1/ge;
           $string =~ s/=[\n\r]+$//;

       Whereas a QP decoder that works on both ASCII and EBCDIC platforms would look somewhat
       like the following (where the @a2e array is omitted for brevity):

           $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr $a2e[hex $1]/ge;
           $string =~ s/=[\n\r]+$//;

   Caesarean ciphers
       The practice of shifting an alphabet one or more characters for encipherment dates back
       thousands of years and was explicitly detailed by Gaius Julius Caesar in his Gallic Wars
       text.  A single alphabet shift is sometimes referred to as a rotation and the shift amount
       is given as a number $n after the string 'rot' or "rot$n".  Rot0 and rot26 would designate
       identity maps on the 26-letter English version of the Latin alphabet.  Rot13 has the
       interesting property that alternate subsequent invocations are identity maps (thus rot13
       is its own non-trivial inverse in the group of 26 alphabet rotations).  Hence the
       following is a rot13 encoder and decoder that will work on ASCII and EBCDIC platforms:

           #!/usr/local/bin/perl

           while(<>){
               tr/n-za-mN-ZA-M/a-zA-Z/;
               print;
           }

       In one-liner form:

           perl -ne 'tr/n-za-mN-ZA-M/a-zA-Z/;print'

Hashing order and checksums

       To the extent that it is possible to write code that depends on hashing order there may be
       differences between hashes as stored on an ASCII-based platform and hashes stored on an
       EBCDIC-based platform.  XXX

I18N AND L10N

       Internationalization (I18N) and localization (L10N) are supported at least in principle
       even on EBCDIC platforms.  The details are system-dependent and discussed under the "OS
       ISSUES" in perlebcdic section below.

MULTI-OCTET CHARACTER SETS

       Perl may work with an internal UTF-EBCDIC encoding form for wide characters on EBCDIC
       platforms in a manner analogous to the way that it works with the UTF-8 internal encoding
       form on ASCII based platforms.

       Legacy multi byte EBCDIC code pages XXX.

OS ISSUES

       There may be a few system-dependent issues of concern to EBCDIC Perl programmers.

   OS/400
       PASE    The PASE environment is a runtime environment for OS/400 that can run executables
               built for PowerPC AIX in OS/400; see perlos400.  PASE is ASCII-based, not EBCDIC-
               based as the ILE.

       IFS access
               XXX.

   OS/390, z/OS
       Perl runs under Unix Systems Services or USS.

       chcp    chcp is supported as a shell utility for displaying and changing one's code page.
               See also chcp(1).

       dataset access
               For sequential data set access try:

                   my @ds_records = `cat //DSNAME`;

               or:

                   my @ds_records = `cat //'HLQ.DSNAME'`;

               See also the OS390::Stdio module on CPAN.

       OS/390, z/OS iconv
               iconv is supported as both a shell utility and a C RTL routine.  See also the
               iconv(1) and iconv(3) manual pages.

       locales On OS/390 or z/OS see locale for information on locales.  The L10N files are in
               /usr/nls/locale.  $Config{d_setlocale} is 'define' on OS/390 or z/OS.

   POSIX-BC?
       XXX.

BUGS

       This pod document contains literal Latin 1 characters and may encounter translation
       difficulties.  In particular one popular nroff implementation was known to strip accented
       characters to their unaccented counterparts while attempting to view this document through
       the pod2man program (for example, you may see a plain "y" rather than one with a diaeresis
       as in ye).  Another nroff truncated the resultant manpage at the first occurrence of 8 bit
       characters.

       Not all shells will allow multiple "-e" string arguments to perl to be concatenated
       together properly as recipes 0, 2, 4, 5, and 6 might seem to imply.

SEE ALSO

       perllocale, perlfunc, perlunicode, utf8.

REFERENCES

       <http://anubis.dkuug.dk/i18n/charmaps>

       <http://www.unicode.org/>

       <http://www.unicode.org/unicode/reports/tr16/>

       <http://www.wps.com/projects/codes/> ASCII: American Standard Code for Information
       Infiltration Tom Jennings, September 1999.

       The Unicode Standard, Version 3.0 The Unicode Consortium, Lisa Moore ed., ISBN
       0-201-61633-5, Addison Wesley Developers Press, February 2000.

       CDRA: IBM - Character Data Representation Architecture - Reference and Registry, IBM
       SC09-2190-00, December 1996.

       "Demystifying Character Sets", Andrea Vine, Multilingual Computing & Technology, #26 Vol.
       10 Issue 4, August/September 1999; ISSN 1523-0309; Multilingual Computing Inc. Sandpoint
       ID, USA.

       Codes, Ciphers, and Other Cryptic and Clandestine Communication Fred B. Wrixon, ISBN
       1-57912-040-7, Black Dog & Leventhal Publishers, 1998.

       <http://www.bobbemer.com/P-BIT.HTM> IBM - EBCDIC and the P-bit; The biggest Computer Goof
       Ever Robert Bemer.

HISTORY

       15 April 2001: added UTF-8 and UTF-EBCDIC to main table, pvhp.

AUTHOR

       Peter Prymmer pvhp@best.com wrote this in 1999 and 2000 with CCSID 0819 and 0037 help from
       Chris Leach and Andre Pirard A.Pirard@ulg.ac.be as well as POSIX-BC help from Thomas
       Dorner Thomas.Dorner@start.de.  Thanks also to Vickie Cooper, Philip Newton, William
       Raffloer, and Joe Smith.  Trademarks, registered trademarks, service marks and registered
       service marks used in this document are the property of their respective owners.