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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.

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 a "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 slightly different single and multi byte coded character
       sets that are different from ASCII or ISO 8859-1 and 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.  Leading
       zero digits in CCSID numbers within this document are insignificant.
       E.g. CCSID 0037 may be referred to as 37 in places.

       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 37 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 other 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 37 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 non-printing control character names as well as the Latin 1
       extensions to ASCII have been labelled with character names roughly
       corresponding to The Unicode Standard, Version 3.0 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 (the "charnames" pragma names unfortunately do not list explicit
       names for the C0 or C1 control characters).  The "names" of the C1
       control set (128..159 in ISO 8859-1) listed here are somewhat
       arbitrary.  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 version of this document since this recipe may not work with a
       pod2_other_format translation) through:

       recipe 0

           perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
            -e '{printf("%s%-9o%-9o%-9o%o\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 (/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/)  {
                   if ($7 ne '' && $9 ne '') {
                       printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%-3o.%o\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
                   }
                   elsif ($7 ne '') {
                       printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%o\n",$1,$2,$3,$4,$5,$6,$7,$8);
                   }
                   else {
                       printf("%s%-9o%-9o%-9o%-9o%-9o%o\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(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
            -e '{printf("%s%-9X%-9X%-9X%X\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 (/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/)  {
                   if ($7 ne '' && $9 ne '') {
                       printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%-2X.%X\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
                   }
                   elsif ($7 ne '') {
                       printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%X\n",$1,$2,$3,$4,$5,$6,$7,$8);
                   }
                   else {
                       printf("%s%-9X%-9X%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5,$6,$8);
                   }
               }
           }

                                                                            incomp-  incomp-
                                        8859-1                              lete     lete
           chr                          0819     0037     1047     POSIX-BC UTF-8    UTF-EBCDIC
           ------------------------------------------------------------------------------------
           <NULL>                       0        0        0        0        0        0
           <START OF HEADING>           1        1        1        1        1        1
           <START OF TEXT>              2        2        2        2        2        2
           <END OF TEXT>                3        3        3        3        3        3
           <END OF TRANSMISSION>        4        55       55       55       4        55
           <ENQUIRY>                    5        45       45       45       5        45
           <ACKNOWLEDGE>                6        46       46       46       6        46
           <BELL>                       7        47       47       47       7        47
           <BACKSPACE>                  8        22       22       22       8        22
           <HORIZONTAL TABULATION>      9        5        5        5        9        5
           <LINE FEED>                  10       37       21       21       10       21       ***
           <VERTICAL TABULATION>        11       11       11       11       11       11
           <FORM FEED>                  12       12       12       12       12       12
           <CARRIAGE RETURN>            13       13       13       13       13       13
           <SHIFT OUT>                  14       14       14       14       14       14
           <SHIFT IN>                   15       15       15       15       15       15
           <DATA LINK ESCAPE>           16       16       16       16       16       16
           <DEVICE CONTROL ONE>         17       17       17       17       17       17
           <DEVICE CONTROL TWO>         18       18       18       18       18       18
           <DEVICE CONTROL THREE>       19       19       19       19       19       19
           <DEVICE CONTROL FOUR>        20       60       60       60       20       60
           <NEGATIVE ACKNOWLEDGE>       21       61       61       61       21       61
           <SYNCHRONOUS IDLE>           22       50       50       50       22       50
           <END OF TRANSMISSION BLOCK>  23       38       38       38       23       38
           <CANCEL>                     24       24       24       24       24       24
           <END OF MEDIUM>              25       25       25       25       25       25
           <SUBSTITUTE>                 26       63       63       63       26       63
           <ESCAPE>                     27       39       39       39       27       39
           <FILE SEPARATOR>             28       28       28       28       28       28
           <GROUP SEPARATOR>            29       29       29       29       29       29
           <RECORD SEPARATOR>           30       30       30       30       30       30
           <UNIT SEPARATOR>             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      ###
           <DELETE>                     127      7        7        7        127      7
           <C1 0>                       128      32       32       32       194.128  32
           <C1 1>                       129      33       33       33       194.129  33
           <C1 2>                       130      34       34       34       194.130  34
           <C1 3>                       131      35       35       35       194.131  35
           <C1 4>                       132      36       36       36       194.132  36
           <C1 5>                       133      21       37       37       194.133  37       ***
           <C1 6>                       134      6        6        6        194.134  6
           <C1 7>                       135      23       23       23       194.135  23
           <C1 8>                       136      40       40       40       194.136  40
           <C1 9>                       137      41       41       41       194.137  41
           <C1 10>                      138      42       42       42       194.138  42
           <C1 11>                      139      43       43       43       194.139  43
           <C1 12>                      140      44       44       44       194.140  44
           <C1 13>                      141      9        9        9        194.141  9
           <C1 14>                      142      10       10       10       194.142  10
           <C1 15>                      143      27       27       27       194.143  27
           <C1 16>                      144      48       48       48       194.144  48
           <C1 17>                      145      49       49       49       194.145  49
           <C1 18>                      146      26       26       26       194.146  26
           <C1 19>                      147      51       51       51       194.147  51
           <C1 20>                      148      52       52       52       194.148  52
           <C1 21>                      149      53       53       53       194.149  53
           <C1 22>                      150      54       54       54       194.150  54
           <C1 23>                      151      8        8        8        194.151  8
           <C1 24>                      152      56       56       56       194.152  56
           <C1 25>                      153      57       57       57       194.153  57
           <C1 26>                      154      58       58       58       194.154  58
           <C1 27>                      155      59       59       59       194.155  59
           <C1 28>                      156      4        4        4        194.156  4
           <C1 29>                      157      20       20       20       194.157  20
           <C1 30>                      158      62       62       62       194.158  62
           <C1 31>                      159      255      255      95       194.159  255      ###
           <NON-BREAKING SPACE>         160      65       65       65       194.160  128.65
           <INVERTED EXCLAMATION MARK>  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 INDICATOR> 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 SIGN> 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(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
            -e '{push(@l,$_)}' \
            -e 'END{print map{$_->[0]}' \
            -e '          sort{$a->[1] <=> $b->[1]}' \
            -e '          map{[$_,substr($_,42,3)]}@l;}' perlebcdic.pod

       If you would rather see it in CCSID 1047 order then change the digit 42
       in the last line to 51, like this:

       recipe 5

           perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
            -e '{push(@l,$_)}' \
            -e 'END{print map{$_->[0]}' \
            -e '          sort{$a->[1] <=> $b->[1]}' \
            -e '          map{[$_,substr($_,51,3)]}@l;}' perlebcdic.pod

       If you would rather see it in POSIX-BC order then change the digit 51
       in the last line to 60, like this:

       recipe 6

           perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
            -e '{push(@l,$_)}' \
            -e 'END{print map{$_->[0]}' \
            -e '          sort{$a->[1] <=> $b->[1]}' \
            -e '          map{[$_,substr($_,60,3)]}@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

   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 order hence the EBCDIC columns
       provide easy to use ASCII to EBCDIC operations that are also easily
       reversed.

       For example, to convert ASCII to code page 037 take the output of the
       second column from the output of recipe 0 (modified to add \\
       characters) and use it in tr/// like so:

           $cp_037 =
           '\000\001\002\003\234\011\206\177\227\215\216\013\014\015\016\017' .
           '\020\021\022\023\235\205\010\207\030\031\222\217\034\035\036\037' .
           '\200\201\202\203\204\012\027\033\210\211\212\213\214\005\006\007' .
           '\220\221\026\223\224\225\226\004\230\231\232\233\024\025\236\032' .
           '\040\240\342\344\340\341\343\345\347\361\242\056\074\050\053\174' .
           '\046\351\352\353\350\355\356\357\354\337\041\044\052\051\073\254' .
           '\055\057\302\304\300\301\303\305\307\321\246\054\045\137\076\077' .
           '\370\311\312\313\310\315\316\317\314\140\072\043\100\047\075\042' .
           '\330\141\142\143\144\145\146\147\150\151\253\273\360\375\376\261' .
           '\260\152\153\154\155\156\157\160\161\162\252\272\346\270\306\244' .
           '\265\176\163\164\165\166\167\170\171\172\241\277\320\335\336\256' .
           '\136\243\245\267\251\247\266\274\275\276\133\135\257\250\264\327' .
           '\173\101\102\103\104\105\106\107\110\111\255\364\366\362\363\365' .
           '\175\112\113\114\115\116\117\120\121\122\271\373\374\371\372\377' .
           '\134\367\123\124\125\126\127\130\131\132\262\324\326\322\323\325' .
           '\060\061\062\063\064\065\066\067\070\071\263\333\334\331\332\237' ;

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

       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/\000-\377/' . $cp_037 . '/';

       Similarly one could take the output of the third column from recipe 0
       to obtain a $cp_1047 table.  The fourth column of the output from
       recipe 0 could provide a $cp_posix_bc table suitable for transcoding as
       well.

   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) as well, but the thirty three characters that result depend
       on which code page you are using.  The table below uses the character
       names from the previous table but with substitutions such as s/START
       OF/S.O./; s/END OF /E.O./; s/TRANSMISSION/TRANS./; s/TABULATION/TAB./;
       s/VERTICAL/VERT./; s/HORIZONTAL/HORIZ./; s/DEVICE CONTROL/D.C./;
       s/SEPARATOR/SEP./; s/NEGATIVE ACKNOWLEDGE/NEG. ACK./;.  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\\" maps to two
       characters not one.

           chr   ord  8859-1               0037                1047 && POSIX-BC
           ------------------------------------------------------------------------
           "\c?" 127  <DELETE>             "                   "              ***><
           "\c@"   0  <NULL>               <NULL>              <NULL>         ***><
           "\cA"   1  <S.O. HEADING>       <S.O. HEADING>      <S.O. HEADING>
           "\cB"   2  <S.O. TEXT>          <S.O. TEXT>         <S.O. TEXT>
           "\cC"   3  <E.O. TEXT>          <E.O. TEXT>         <E.O. TEXT>
           "\cD"   4  <E.O. TRANS.>        <C1 28>             <C1 28>
           "\cE"   5  <ENQUIRY>            <HORIZ. TAB.>       <HORIZ. TAB.>
           "\cF"   6  <ACKNOWLEDGE>        <C1 6>              <C1 6>
           "\cG"   7  <BELL>               <DELETE>            <DELETE>
           "\cH"   8  <BACKSPACE>          <C1 23>             <C1 23>
           "\cI"   9  <HORIZ. TAB.>        <C1 13>             <C1 13>
           "\cJ"  10  <LINE FEED>          <C1 14>             <C1 14>
           "\cK"  11  <VERT. TAB.>         <VERT. TAB.>        <VERT. TAB.>
           "\cL"  12  <FORM FEED>          <FORM FEED>         <FORM FEED>
           "\cM"  13  <CARRIAGE RETURN>    <CARRIAGE RETURN>   <CARRIAGE RETURN>
           "\cN"  14  <SHIFT OUT>          <SHIFT OUT>         <SHIFT OUT>
           "\cO"  15  <SHIFT IN>           <SHIFT IN>          <SHIFT IN>
           "\cP"  16  <DATA LINK ESCAPE>   <DATA LINK ESCAPE>  <DATA LINK ESCAPE>
           "\cQ"  17  <D.C. ONE>           <D.C. ONE>          <D.C. ONE>
           "\cR"  18  <D.C. TWO>           <D.C. TWO>          <D.C. TWO>
           "\cS"  19  <D.C. THREE>         <D.C. THREE>        <D.C. THREE>
           "\cT"  20  <D.C. FOUR>          <C1 29>             <C1 29>
           "\cU"  21  <NEG. ACK.>          <C1 5>              <LINE FEED>    ***
           "\cV"  22  <SYNCHRONOUS IDLE>   <BACKSPACE>         <BACKSPACE>
           "\cW"  23  <E.O. TRANS. BLOCK>  <C1 7>              <C1 7>
           "\cX"  24  <CANCEL>             <CANCEL>            <CANCEL>
           "\cY"  25  <E.O. MEDIUM>        <E.O. MEDIUM>       <E.O. MEDIUM>
           "\cZ"  26  <SUBSTITUTE>         <C1 18>             <C1 18>
           "\c["  27  <ESCAPE>             <C1 15>             <C1 15>
           "\c\\" 28  <FILE SEP.>\         <FILE SEP.>\        <FILE SEP.>\
           "\c]"  29  <GROUP SEP.>         <GROUP SEP.>        <GROUP SEP.>
           "\c^"  30  <RECORD SEP.>        <RECORD SEP.>       <RECORD SEP.>  ***><
           "\c_"  31  <UNIT SEP.>          <UNIT SEP.>         <UNIT SEP.>    ***><

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 alia

               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 expression 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) { # 37
                   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) { # 37
                   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) { # 37
                   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~AeAaCEEEEeIIIIe‐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
       for drive, that is:

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

       The property of lower case 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 upper case 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 test 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~AeAaCEEEEeIIIIe‐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;
           $string =~ s/=[\n\r]+$//;

   Caesarian 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 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.

       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.

   VM/ESA?
       XXX.

   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/texts/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.