xref: /onnv-gate/usr/src/cmd/perl/5.8.4/distrib/pod/perlebcdic.pod (revision 0:68f95e015346)
1=head1 NAME
2
3perlebcdic - Considerations for running Perl on EBCDIC platforms
4
5=head1 DESCRIPTION
6
7An exploration of some of the issues facing Perl programmers
8on EBCDIC based computers.  We do not cover localization,
9internationalization, or multi byte character set issues other
10than some discussion of UTF-8 and UTF-EBCDIC.
11
12Portions that are still incomplete are marked with XXX.
13
14=head1 COMMON CHARACTER CODE SETS
15
16=head2 ASCII
17
18The American Standard Code for Information Interchange is a set of
19integers running from 0 to 127 (decimal) that imply character
20interpretation by the display and other system(s) of computers.
21The range 0..127 can be covered by setting the bits in a 7-bit binary
22digit, hence the set is sometimes referred to as a "7-bit ASCII".
23ASCII was described by the American National Standards Institute
24document ANSI X3.4-1986.  It was also described by ISO 646:1991
25(with localization for currency symbols).  The full ASCII set is
26given in the table below as the first 128 elements.  Languages that
27can be written adequately with the characters in ASCII include
28English, Hawaiian, Indonesian, Swahili and some Native American
29languages.
30
31There are many character sets that extend the range of integers
32from 0..2**7-1 up to 2**8-1, or 8 bit bytes (octets if you prefer).
33One common one is the ISO 8859-1 character set.
34
35=head2 ISO 8859
36
37The ISO 8859-$n are a collection of character code sets from the
38International Organization for Standardization (ISO) each of which
39adds characters to the ASCII set that are typically found in European
40languages many of which are based on the Roman, or Latin, alphabet.
41
42=head2 Latin 1 (ISO 8859-1)
43
44A particular 8-bit extension to ASCII that includes grave and acute
45accented Latin characters.  Languages that can employ ISO 8859-1
46include all the languages covered by ASCII as well as Afrikaans,
47Albanian, Basque, Catalan, Danish, Faroese, Finnish, Norwegian,
48Portuguese, Spanish, and Swedish.  Dutch is covered albeit without
49the ij ligature.  French is covered too but without the oe ligature.
50German can use ISO 8859-1 but must do so without German-style
51quotation marks.  This set is based on Western European extensions
52to ASCII and is commonly encountered in world wide web work.
53In IBM character code set identification terminology ISO 8859-1 is
54also known as CCSID 819 (or sometimes 0819 or even 00819).
55
56=head2 EBCDIC
57
58The Extended Binary Coded Decimal Interchange Code refers to a
59large collection of slightly different single and multi byte
60coded character sets that are different from ASCII or ISO 8859-1
61and typically run on host computers.  The EBCDIC encodings derive
62from 8 bit byte extensions of Hollerith punched card encodings.
63The layout on the cards was such that high bits were set for the
64upper and lower case alphabet characters [a-z] and [A-Z], but there
65were gaps within each latin alphabet range.
66
67Some IBM EBCDIC character sets may be known by character code set
68identification numbers (CCSID numbers) or code page numbers.  Leading
69zero digits in CCSID numbers within this document are insignificant.
70E.g. CCSID 0037 may be referred to as 37 in places.
71
72=head2 13 variant characters
73
74Among IBM EBCDIC character code sets there are 13 characters that
75are often mapped to different integer values.  Those characters
76are known as the 13 "variant" characters and are:
77
78    \ [ ] { } ^ ~ ! # | $ @ `
79
80=head2 0037
81
82Character code set ID 0037 is a mapping of the ASCII plus Latin-1
83characters (i.e. ISO 8859-1) to an EBCDIC set.  0037 is used
84in North American English locales on the OS/400 operating system
85that runs on AS/400 computers.  CCSID 37 differs from ISO 8859-1
86in 237 places, in other words they agree on only 19 code point values.
87
88=head2 1047
89
90Character code set ID 1047 is also a mapping of the ASCII plus
91Latin-1 characters (i.e. ISO 8859-1) to an EBCDIC set.  1047 is
92used under Unix System Services for OS/390 or z/OS, and OpenEdition
93for VM/ESA.  CCSID 1047 differs from CCSID 0037 in eight places.
94
95=head2 POSIX-BC
96
97The EBCDIC code page in use on Siemens' BS2000 system is distinct from
981047 and 0037.  It is identified below as the POSIX-BC set.
99
100=head2 Unicode code points versus EBCDIC code points
101
102In Unicode terminology a I<code point> is the number assigned to a
103character: for example, in EBCDIC the character "A" is usually assigned
104the number 193.  In Unicode the character "A" is assigned the number 65.
105This causes a problem with the semantics of the pack/unpack "U", which
106are supposed to pack Unicode code points to characters and back to numbers.
107The problem is: which code points to use for code points less than 256?
108(for 256 and over there's no problem: Unicode code points are used)
109In EBCDIC, for the low 256 the EBCDIC code points are used.  This
110means that the equivalences
111
112	pack("U", ord($character)) eq $character
113	unpack("U", $character) == ord $character
114
115will hold.  (If Unicode code points were applied consistently over
116all the possible code points, pack("U",ord("A")) would in EBCDIC
117equal I<A with acute> or chr(101), and unpack("U", "A") would equal
11865, or I<non-breaking space>, not 193, or ord "A".)
119
120=head2 Remaining Perl Unicode problems in EBCDIC
121
122=over 4
123
124=item *
125
126Many of the remaining seem to be related to case-insensitive matching:
127for example, C<< /[\x{131}]/ >> (LATIN SMALL LETTER DOTLESS I) does
128not match "I" case-insensitively, as it should under Unicode.
129(The match succeeds in ASCII-derived platforms.)
130
131=item *
132
133The extensions Unicode::Collate and Unicode::Normalized are not
134supported under EBCDIC, likewise for the encoding pragma.
135
136=back
137
138=head2 Unicode and UTF
139
140UTF is a Unicode Transformation Format.  UTF-8 is a Unicode conforming
141representation of the Unicode standard that looks very much like ASCII.
142UTF-EBCDIC is an attempt to represent Unicode characters in an EBCDIC
143transparent manner.
144
145=head2 Using Encode
146
147Starting from Perl 5.8 you can use the standard new module Encode
148to translate from EBCDIC to Latin-1 code points
149
150	use Encode 'from_to';
151
152	my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );
153
154	# $a is in EBCDIC code points
155	from_to($a, $ebcdic{ord '^'}, 'latin1');
156	# $a is ISO 8859-1 code points
157
158and from Latin-1 code points to EBCDIC code points
159
160	use Encode 'from_to';
161
162	my %ebcdic = ( 176 => 'cp37', 95 => 'cp1047', 106 => 'posix-bc' );
163
164	# $a is ISO 8859-1 code points
165	from_to($a, 'latin1', $ebcdic{ord '^'});
166	# $a is in EBCDIC code points
167
168For doing I/O it is suggested that you use the autotranslating features
169of PerlIO, see L<perluniintro>.
170
171Since version 5.8 Perl uses the new PerlIO I/O library.  This enables
172you to use different encodings per IO channel.  For example you may use
173
174    use Encode;
175    open($f, ">:encoding(ascii)", "test.ascii");
176    print $f "Hello World!\n";
177    open($f, ">:encoding(cp37)", "test.ebcdic");
178    print $f "Hello World!\n";
179    open($f, ">:encoding(latin1)", "test.latin1");
180    print $f "Hello World!\n";
181    open($f, ">:encoding(utf8)", "test.utf8");
182    print $f "Hello World!\n";
183
184to get two files containing "Hello World!\n" in ASCII, CP 37 EBCDIC,
185ISO 8859-1 (Latin-1) (in this example identical to ASCII) respective
186UTF-EBCDIC (in this example identical to normal EBCDIC).  See the
187documentation of Encode::PerlIO for details.
188
189As the PerlIO layer uses raw IO (bytes) internally, all this totally
190ignores things like the type of your filesystem (ASCII or EBCDIC).
191
192=head1 SINGLE OCTET TABLES
193
194The following tables list the ASCII and Latin 1 ordered sets including
195the subsets: C0 controls (0..31), ASCII graphics (32..7e), delete (7f),
196C1 controls (80..9f), and Latin-1 (a.k.a. ISO 8859-1) (a0..ff).  In the
197table non-printing control character names as well as the Latin 1
198extensions to ASCII have been labelled with character names roughly
199corresponding to I<The Unicode Standard, Version 3.0> albeit with
200substitutions such as s/LATIN// and s/VULGAR// in all cases,
201s/CAPITAL LETTER// in some cases, and s/SMALL LETTER ([A-Z])/\l$1/
202in some other cases (the C<charnames> pragma names unfortunately do
203not list explicit names for the C0 or C1 control characters).  The
204"names" of the C1 control set (128..159 in ISO 8859-1) listed here are
205somewhat arbitrary.  The differences between the 0037 and 1047 sets are
206flagged with ***.  The differences between the 1047 and POSIX-BC sets
207are flagged with ###.  All ord() numbers listed are decimal.  If you
208would rather see this table listing octal values then run the table
209(that is, the pod version of this document since this recipe may not
210work with a pod2_other_format translation) through:
211
212=over 4
213
214=item recipe 0
215
216=back
217
218    perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
219     -e '{printf("%s%-9o%-9o%-9o%o\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
220
221If you want to retain the UTF-x code points then in script form you
222might want to write:
223
224=over 4
225
226=item recipe 1
227
228=back
229
230    open(FH,"<perlebcdic.pod") or die "Could not open perlebcdic.pod: $!";
231    while (<FH>) {
232        if (/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/)  {
233            if ($7 ne '' && $9 ne '') {
234                printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%-3o.%o\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
235            }
236            elsif ($7 ne '') {
237                printf("%s%-9o%-9o%-9o%-9o%-3o.%-5o%o\n",$1,$2,$3,$4,$5,$6,$7,$8);
238            }
239            else {
240                printf("%s%-9o%-9o%-9o%-9o%-9o%o\n",$1,$2,$3,$4,$5,$6,$8);
241            }
242        }
243    }
244
245If you would rather see this table listing hexadecimal values then
246run the table through:
247
248=over 4
249
250=item recipe 2
251
252=back
253
254    perl -ne 'if(/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/)' \
255     -e '{printf("%s%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5)}' perlebcdic.pod
256
257Or, in order to retain the UTF-x code points in hexadecimal:
258
259=over 4
260
261=item recipe 3
262
263=back
264
265    open(FH,"<perlebcdic.pod") or die "Could not open perlebcdic.pod: $!";
266    while (<FH>) {
267        if (/(.{33})(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\.?(\d*)\s+(\d+)\.?(\d*)/)  {
268            if ($7 ne '' && $9 ne '') {
269                printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%-2X.%X\n",$1,$2,$3,$4,$5,$6,$7,$8,$9);
270            }
271            elsif ($7 ne '') {
272                printf("%s%-9X%-9X%-9X%-9X%-2X.%-6X%X\n",$1,$2,$3,$4,$5,$6,$7,$8);
273            }
274            else {
275                printf("%s%-9X%-9X%-9X%-9X%-9X%X\n",$1,$2,$3,$4,$5,$6,$8);
276            }
277        }
278    }
279
280
281                                                                     incomp-  incomp-
282                                 8859-1                              lete     lete
283    chr                          0819     0037     1047     POSIX-BC UTF-8    UTF-EBCDIC
284    ------------------------------------------------------------------------------------
285    <NULL>                       0        0        0        0        0        0
286    <START OF HEADING>           1        1        1        1        1        1
287    <START OF TEXT>              2        2        2        2        2        2
288    <END OF TEXT>                3        3        3        3        3        3
289    <END OF TRANSMISSION>        4        55       55       55       4        55
290    <ENQUIRY>                    5        45       45       45       5        45
291    <ACKNOWLEDGE>                6        46       46       46       6        46
292    <BELL>                       7        47       47       47       7        47
293    <BACKSPACE>                  8        22       22       22       8        22
294    <HORIZONTAL TABULATION>      9        5        5        5        9        5
295    <LINE FEED>                  10       37       21       21       10       21       ***
296    <VERTICAL TABULATION>        11       11       11       11       11       11
297    <FORM FEED>                  12       12       12       12       12       12
298    <CARRIAGE RETURN>            13       13       13       13       13       13
299    <SHIFT OUT>                  14       14       14       14       14       14
300    <SHIFT IN>                   15       15       15       15       15       15
301    <DATA LINK ESCAPE>           16       16       16       16       16       16
302    <DEVICE CONTROL ONE>         17       17       17       17       17       17
303    <DEVICE CONTROL TWO>         18       18       18       18       18       18
304    <DEVICE CONTROL THREE>       19       19       19       19       19       19
305    <DEVICE CONTROL FOUR>        20       60       60       60       20       60
306    <NEGATIVE ACKNOWLEDGE>       21       61       61       61       21       61
307    <SYNCHRONOUS IDLE>           22       50       50       50       22       50
308    <END OF TRANSMISSION BLOCK>  23       38       38       38       23       38
309    <CANCEL>                     24       24       24       24       24       24
310    <END OF MEDIUM>              25       25       25       25       25       25
311    <SUBSTITUTE>                 26       63       63       63       26       63
312    <ESCAPE>                     27       39       39       39       27       39
313    <FILE SEPARATOR>             28       28       28       28       28       28
314    <GROUP SEPARATOR>            29       29       29       29       29       29
315    <RECORD SEPARATOR>           30       30       30       30       30       30
316    <UNIT SEPARATOR>             31       31       31       31       31       31
317    <SPACE>                      32       64       64       64       32       64
318    !                            33       90       90       90       33       90
319    "                            34       127      127      127      34       127
320    #                            35       123      123      123      35       123
321    $                            36       91       91       91       36       91
322    %                            37       108      108      108      37       108
323    &                            38       80       80       80       38       80
324    '                            39       125      125      125      39       125
325    (                            40       77       77       77       40       77
326    )                            41       93       93       93       41       93
327    *                            42       92       92       92       42       92
328    +                            43       78       78       78       43       78
329    ,                            44       107      107      107      44       107
330    -                            45       96       96       96       45       96
331    .                            46       75       75       75       46       75
332    /                            47       97       97       97       47       97
333    0                            48       240      240      240      48       240
334    1                            49       241      241      241      49       241
335    2                            50       242      242      242      50       242
336    3                            51       243      243      243      51       243
337    4                            52       244      244      244      52       244
338    5                            53       245      245      245      53       245
339    6                            54       246      246      246      54       246
340    7                            55       247      247      247      55       247
341    8                            56       248      248      248      56       248
342    9                            57       249      249      249      57       249
343    :                            58       122      122      122      58       122
344    ;                            59       94       94       94       59       94
345    <                            60       76       76       76       60       76
346    =                            61       126      126      126      61       126
347    >                            62       110      110      110      62       110
348    ?                            63       111      111      111      63       111
349    @                            64       124      124      124      64       124
350    A                            65       193      193      193      65       193
351    B                            66       194      194      194      66       194
352    C                            67       195      195      195      67       195
353    D                            68       196      196      196      68       196
354    E                            69       197      197      197      69       197
355    F                            70       198      198      198      70       198
356    G                            71       199      199      199      71       199
357    H                            72       200      200      200      72       200
358    I                            73       201      201      201      73       201
359    J                            74       209      209      209      74       209
360    K                            75       210      210      210      75       210
361    L                            76       211      211      211      76       211
362    M                            77       212      212      212      77       212
363    N                            78       213      213      213      78       213
364    O                            79       214      214      214      79       214
365    P                            80       215      215      215      80       215
366    Q                            81       216      216      216      81       216
367    R                            82       217      217      217      82       217
368    S                            83       226      226      226      83       226
369    T                            84       227      227      227      84       227
370    U                            85       228      228      228      85       228
371    V                            86       229      229      229      86       229
372    W                            87       230      230      230      87       230
373    X                            88       231      231      231      88       231
374    Y                            89       232      232      232      89       232
375    Z                            90       233      233      233      90       233
376    [                            91       186      173      187      91       173      *** ###
377    \                            92       224      224      188      92       224      ###
378    ]                            93       187      189      189      93       189      ***
379    ^                            94       176      95       106      94       95       *** ###
380    _                            95       109      109      109      95       109
381    `                            96       121      121      74       96       121      ###
382    a                            97       129      129      129      97       129
383    b                            98       130      130      130      98       130
384    c                            99       131      131      131      99       131
385    d                            100      132      132      132      100      132
386    e                            101      133      133      133      101      133
387    f                            102      134      134      134      102      134
388    g                            103      135      135      135      103      135
389    h                            104      136      136      136      104      136
390    i                            105      137      137      137      105      137
391    j                            106      145      145      145      106      145
392    k                            107      146      146      146      107      146
393    l                            108      147      147      147      108      147
394    m                            109      148      148      148      109      148
395    n                            110      149      149      149      110      149
396    o                            111      150      150      150      111      150
397    p                            112      151      151      151      112      151
398    q                            113      152      152      152      113      152
399    r                            114      153      153      153      114      153
400    s                            115      162      162      162      115      162
401    t                            116      163      163      163      116      163
402    u                            117      164      164      164      117      164
403    v                            118      165      165      165      118      165
404    w                            119      166      166      166      119      166
405    x                            120      167      167      167      120      167
406    y                            121      168      168      168      121      168
407    z                            122      169      169      169      122      169
408    {                            123      192      192      251      123      192      ###
409    |                            124      79       79       79       124      79
410    }                            125      208      208      253      125      208      ###
411    ~                            126      161      161      255      126      161      ###
412    <DELETE>                     127      7        7        7        127      7
413    <C1 0>                       128      32       32       32       194.128  32
414    <C1 1>                       129      33       33       33       194.129  33
415    <C1 2>                       130      34       34       34       194.130  34
416    <C1 3>                       131      35       35       35       194.131  35
417    <C1 4>                       132      36       36       36       194.132  36
418    <C1 5>                       133      21       37       37       194.133  37       ***
419    <C1 6>                       134      6        6        6        194.134  6
420    <C1 7>                       135      23       23       23       194.135  23
421    <C1 8>                       136      40       40       40       194.136  40
422    <C1 9>                       137      41       41       41       194.137  41
423    <C1 10>                      138      42       42       42       194.138  42
424    <C1 11>                      139      43       43       43       194.139  43
425    <C1 12>                      140      44       44       44       194.140  44
426    <C1 13>                      141      9        9        9        194.141  9
427    <C1 14>                      142      10       10       10       194.142  10
428    <C1 15>                      143      27       27       27       194.143  27
429    <C1 16>                      144      48       48       48       194.144  48
430    <C1 17>                      145      49       49       49       194.145  49
431    <C1 18>                      146      26       26       26       194.146  26
432    <C1 19>                      147      51       51       51       194.147  51
433    <C1 20>                      148      52       52       52       194.148  52
434    <C1 21>                      149      53       53       53       194.149  53
435    <C1 22>                      150      54       54       54       194.150  54
436    <C1 23>                      151      8        8        8        194.151  8
437    <C1 24>                      152      56       56       56       194.152  56
438    <C1 25>                      153      57       57       57       194.153  57
439    <C1 26>                      154      58       58       58       194.154  58
440    <C1 27>                      155      59       59       59       194.155  59
441    <C1 28>                      156      4        4        4        194.156  4
442    <C1 29>                      157      20       20       20       194.157  20
443    <C1 30>                      158      62       62       62       194.158  62
444    <C1 31>                      159      255      255      95       194.159  255      ###
445    <NON-BREAKING SPACE>         160      65       65       65       194.160  128.65
446    <INVERTED EXCLAMATION MARK>  161      170      170      170      194.161  128.66
447    <CENT SIGN>                  162      74       74       176      194.162  128.67   ###
448    <POUND SIGN>                 163      177      177      177      194.163  128.68
449    <CURRENCY SIGN>              164      159      159      159      194.164  128.69
450    <YEN SIGN>                   165      178      178      178      194.165  128.70
451    <BROKEN BAR>                 166      106      106      208      194.166  128.71   ###
452    <SECTION SIGN>               167      181      181      181      194.167  128.72
453    <DIAERESIS>                  168      189      187      121      194.168  128.73   *** ###
454    <COPYRIGHT SIGN>             169      180      180      180      194.169  128.74
455    <FEMININE ORDINAL INDICATOR> 170      154      154      154      194.170  128.81
456    <LEFT POINTING GUILLEMET>    171      138      138      138      194.171  128.82
457    <NOT SIGN>                   172      95       176      186      194.172  128.83   *** ###
458    <SOFT HYPHEN>                173      202      202      202      194.173  128.84
459    <REGISTERED TRADE MARK SIGN> 174      175      175      175      194.174  128.85
460    <MACRON>                     175      188      188      161      194.175  128.86   ###
461    <DEGREE SIGN>                176      144      144      144      194.176  128.87
462    <PLUS-OR-MINUS SIGN>         177      143      143      143      194.177  128.88
463    <SUPERSCRIPT TWO>            178      234      234      234      194.178  128.89
464    <SUPERSCRIPT THREE>          179      250      250      250      194.179  128.98
465    <ACUTE ACCENT>               180      190      190      190      194.180  128.99
466    <MICRO SIGN>                 181      160      160      160      194.181  128.100
467    <PARAGRAPH SIGN>             182      182      182      182      194.182  128.101
468    <MIDDLE DOT>                 183      179      179      179      194.183  128.102
469    <CEDILLA>                    184      157      157      157      194.184  128.103
470    <SUPERSCRIPT ONE>            185      218      218      218      194.185  128.104
471    <MASC. ORDINAL INDICATOR>    186      155      155      155      194.186  128.105
472    <RIGHT POINTING GUILLEMET>   187      139      139      139      194.187  128.106
473    <FRACTION ONE QUARTER>       188      183      183      183      194.188  128.112
474    <FRACTION ONE HALF>          189      184      184      184      194.189  128.113
475    <FRACTION THREE QUARTERS>    190      185      185      185      194.190  128.114
476    <INVERTED QUESTION MARK>     191      171      171      171      194.191  128.115
477    <A WITH GRAVE>               192      100      100      100      195.128  138.65
478    <A WITH ACUTE>               193      101      101      101      195.129  138.66
479    <A WITH CIRCUMFLEX>          194      98       98       98       195.130  138.67
480    <A WITH TILDE>               195      102      102      102      195.131  138.68
481    <A WITH DIAERESIS>           196      99       99       99       195.132  138.69
482    <A WITH RING ABOVE>          197      103      103      103      195.133  138.70
483    <CAPITAL LIGATURE AE>        198      158      158      158      195.134  138.71
484    <C WITH CEDILLA>             199      104      104      104      195.135  138.72
485    <E WITH GRAVE>               200      116      116      116      195.136  138.73
486    <E WITH ACUTE>               201      113      113      113      195.137  138.74
487    <E WITH CIRCUMFLEX>          202      114      114      114      195.138  138.81
488    <E WITH DIAERESIS>           203      115      115      115      195.139  138.82
489    <I WITH GRAVE>               204      120      120      120      195.140  138.83
490    <I WITH ACUTE>               205      117      117      117      195.141  138.84
491    <I WITH CIRCUMFLEX>          206      118      118      118      195.142  138.85
492    <I WITH DIAERESIS>           207      119      119      119      195.143  138.86
493    <CAPITAL LETTER ETH>         208      172      172      172      195.144  138.87
494    <N WITH TILDE>               209      105      105      105      195.145  138.88
495    <O WITH GRAVE>               210      237      237      237      195.146  138.89
496    <O WITH ACUTE>               211      238      238      238      195.147  138.98
497    <O WITH CIRCUMFLEX>          212      235      235      235      195.148  138.99
498    <O WITH TILDE>               213      239      239      239      195.149  138.100
499    <O WITH DIAERESIS>           214      236      236      236      195.150  138.101
500    <MULTIPLICATION SIGN>        215      191      191      191      195.151  138.102
501    <O WITH STROKE>              216      128      128      128      195.152  138.103
502    <U WITH GRAVE>               217      253      253      224      195.153  138.104  ###
503    <U WITH ACUTE>               218      254      254      254      195.154  138.105
504    <U WITH CIRCUMFLEX>          219      251      251      221      195.155  138.106  ###
505    <U WITH DIAERESIS>           220      252      252      252      195.156  138.112
506    <Y WITH ACUTE>               221      173      186      173      195.157  138.113  *** ###
507    <CAPITAL LETTER THORN>       222      174      174      174      195.158  138.114
508    <SMALL LETTER SHARP S>       223      89       89       89       195.159  138.115
509    <a WITH GRAVE>               224      68       68       68       195.160  139.65
510    <a WITH ACUTE>               225      69       69       69       195.161  139.66
511    <a WITH CIRCUMFLEX>          226      66       66       66       195.162  139.67
512    <a WITH TILDE>               227      70       70       70       195.163  139.68
513    <a WITH DIAERESIS>           228      67       67       67       195.164  139.69
514    <a WITH RING ABOVE>          229      71       71       71       195.165  139.70
515    <SMALL LIGATURE ae>          230      156      156      156      195.166  139.71
516    <c WITH CEDILLA>             231      72       72       72       195.167  139.72
517    <e WITH GRAVE>               232      84       84       84       195.168  139.73
518    <e WITH ACUTE>               233      81       81       81       195.169  139.74
519    <e WITH CIRCUMFLEX>          234      82       82       82       195.170  139.81
520    <e WITH DIAERESIS>           235      83       83       83       195.171  139.82
521    <i WITH GRAVE>               236      88       88       88       195.172  139.83
522    <i WITH ACUTE>               237      85       85       85       195.173  139.84
523    <i WITH CIRCUMFLEX>          238      86       86       86       195.174  139.85
524    <i WITH DIAERESIS>           239      87       87       87       195.175  139.86
525    <SMALL LETTER eth>           240      140      140      140      195.176  139.87
526    <n WITH TILDE>               241      73       73       73       195.177  139.88
527    <o WITH GRAVE>               242      205      205      205      195.178  139.89
528    <o WITH ACUTE>               243      206      206      206      195.179  139.98
529    <o WITH CIRCUMFLEX>          244      203      203      203      195.180  139.99
530    <o WITH TILDE>               245      207      207      207      195.181  139.100
531    <o WITH DIAERESIS>           246      204      204      204      195.182  139.101
532    <DIVISION SIGN>              247      225      225      225      195.183  139.102
533    <o WITH STROKE>              248      112      112      112      195.184  139.103
534    <u WITH GRAVE>               249      221      221      192      195.185  139.104  ###
535    <u WITH ACUTE>               250      222      222      222      195.186  139.105
536    <u WITH CIRCUMFLEX>          251      219      219      219      195.187  139.106
537    <u WITH DIAERESIS>           252      220      220      220      195.188  139.112
538    <y WITH ACUTE>               253      141      141      141      195.189  139.113
539    <SMALL LETTER thorn>         254      142      142      142      195.190  139.114
540    <y WITH DIAERESIS>           255      223      223      223      195.191  139.115
541
542If you would rather see the above table in CCSID 0037 order rather than
543ASCII + Latin-1 order then run the table through:
544
545=over 4
546
547=item recipe 4
548
549=back
550
551    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}/)'\
552     -e '{push(@l,$_)}' \
553     -e 'END{print map{$_->[0]}' \
554     -e '          sort{$a->[1] <=> $b->[1]}' \
555     -e '          map{[$_,substr($_,42,3)]}@l;}' perlebcdic.pod
556
557If you would rather see it in CCSID 1047 order then change the digit
55842 in the last line to 51, like this:
559
560=over 4
561
562=item recipe 5
563
564=back
565
566    perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
567     -e '{push(@l,$_)}' \
568     -e 'END{print map{$_->[0]}' \
569     -e '          sort{$a->[1] <=> $b->[1]}' \
570     -e '          map{[$_,substr($_,51,3)]}@l;}' perlebcdic.pod
571
572If you would rather see it in POSIX-BC order then change the digit
57351 in the last line to 60, like this:
574
575=over 4
576
577=item recipe 6
578
579=back
580
581    perl -ne 'if(/.{33}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}\s{6,8}\d{1,3}/)'\
582     -e '{push(@l,$_)}' \
583     -e 'END{print map{$_->[0]}' \
584     -e '          sort{$a->[1] <=> $b->[1]}' \
585     -e '          map{[$_,substr($_,60,3)]}@l;}' perlebcdic.pod
586
587
588=head1 IDENTIFYING CHARACTER CODE SETS
589
590To determine the character set you are running under from perl one
591could use the return value of ord() or chr() to test one or more
592character values.  For example:
593
594    $is_ascii  = "A" eq chr(65);
595    $is_ebcdic = "A" eq chr(193);
596
597Also, "\t" is a C<HORIZONTAL TABULATION> character so that:
598
599    $is_ascii  = ord("\t") == 9;
600    $is_ebcdic = ord("\t") == 5;
601
602To distinguish EBCDIC code pages try looking at one or more of
603the characters that differ between them.  For example:
604
605    $is_ebcdic_37   = "\n" eq chr(37);
606    $is_ebcdic_1047 = "\n" eq chr(21);
607
608Or better still choose a character that is uniquely encoded in any
609of the code sets, e.g.:
610
611    $is_ascii           = ord('[') == 91;
612    $is_ebcdic_37       = ord('[') == 186;
613    $is_ebcdic_1047     = ord('[') == 173;
614    $is_ebcdic_POSIX_BC = ord('[') == 187;
615
616However, it would be unwise to write tests such as:
617
618    $is_ascii = "\r" ne chr(13);  #  WRONG
619    $is_ascii = "\n" ne chr(10);  #  ILL ADVISED
620
621Obviously the first of these will fail to distinguish most ASCII machines
622from either a CCSID 0037, a 1047, or a POSIX-BC EBCDIC machine since "\r" eq
623chr(13) under all of those coded character sets.  But note too that
624because "\n" is chr(13) and "\r" is chr(10) on the MacIntosh (which is an
625ASCII machine) the second C<$is_ascii> test will lead to trouble there.
626
627To determine whether or not perl was built under an EBCDIC
628code page you can use the Config module like so:
629
630    use Config;
631    $is_ebcdic = $Config{'ebcdic'} eq 'define';
632
633=head1 CONVERSIONS
634
635=head2 tr///
636
637In order to convert a string of characters from one character set to
638another a simple list of numbers, such as in the right columns in the
639above table, along with perl's tr/// operator is all that is needed.
640The data in the table are in ASCII order hence the EBCDIC columns
641provide easy to use ASCII to EBCDIC operations that are also easily
642reversed.
643
644For example, to convert ASCII to code page 037 take the output of the second
645column from the output of recipe 0 (modified to add \\ characters) and use
646it in tr/// like so:
647
648    $cp_037 =
649    '\000\001\002\003\234\011\206\177\227\215\216\013\014\015\016\017' .
650    '\020\021\022\023\235\205\010\207\030\031\222\217\034\035\036\037' .
651    '\200\201\202\203\204\012\027\033\210\211\212\213\214\005\006\007' .
652    '\220\221\026\223\224\225\226\004\230\231\232\233\024\025\236\032' .
653    '\040\240\342\344\340\341\343\345\347\361\242\056\074\050\053\174' .
654    '\046\351\352\353\350\355\356\357\354\337\041\044\052\051\073\254' .
655    '\055\057\302\304\300\301\303\305\307\321\246\054\045\137\076\077' .
656    '\370\311\312\313\310\315\316\317\314\140\072\043\100\047\075\042' .
657    '\330\141\142\143\144\145\146\147\150\151\253\273\360\375\376\261' .
658    '\260\152\153\154\155\156\157\160\161\162\252\272\346\270\306\244' .
659    '\265\176\163\164\165\166\167\170\171\172\241\277\320\335\336\256' .
660    '\136\243\245\267\251\247\266\274\275\276\133\135\257\250\264\327' .
661    '\173\101\102\103\104\105\106\107\110\111\255\364\366\362\363\365' .
662    '\175\112\113\114\115\116\117\120\121\122\271\373\374\371\372\377' .
663    '\134\367\123\124\125\126\127\130\131\132\262\324\326\322\323\325' .
664    '\060\061\062\063\064\065\066\067\070\071\263\333\334\331\332\237' ;
665
666    my $ebcdic_string = $ascii_string;
667    eval '$ebcdic_string =~ tr/' . $cp_037 . '/\000-\377/';
668
669To convert from EBCDIC 037 to ASCII just reverse the order of the tr///
670arguments like so:
671
672    my $ascii_string = $ebcdic_string;
673    eval '$ascii_string =~ tr/\000-\377/' . $cp_037 . '/';
674
675Similarly one could take the output of the third column from recipe 0 to
676obtain a C<$cp_1047> table.  The fourth column of the output from recipe
6770 could provide a C<$cp_posix_bc> table suitable for transcoding as well.
678
679=head2 iconv
680
681XPG operability often implies the presence of an I<iconv> utility
682available from the shell or from the C library.  Consult your system's
683documentation for information on iconv.
684
685On OS/390 or z/OS see the iconv(1) manpage.  One way to invoke the iconv
686shell utility from within perl would be to:
687
688    # OS/390 or z/OS example
689    $ascii_data = `echo '$ebcdic_data'| iconv -f IBM-1047 -t ISO8859-1`
690
691or the inverse map:
692
693    # OS/390 or z/OS example
694    $ebcdic_data = `echo '$ascii_data'| iconv -f ISO8859-1 -t IBM-1047`
695
696For other perl based conversion options see the Convert::* modules on CPAN.
697
698=head2 C RTL
699
700The OS/390 and z/OS C run time libraries provide _atoe() and _etoa() functions.
701
702=head1 OPERATOR DIFFERENCES
703
704The C<..> range operator treats certain character ranges with
705care on EBCDIC machines.  For example the following array
706will have twenty six elements on either an EBCDIC machine
707or an ASCII machine:
708
709    @alphabet = ('A'..'Z');   #  $#alphabet == 25
710
711The bitwise operators such as & ^ | may return different results
712when operating on string or character data in a perl program running
713on an EBCDIC machine than when run on an ASCII machine.  Here is
714an example adapted from the one in L<perlop>:
715
716    # EBCDIC-based examples
717    print "j p \n" ^ " a h";                      # prints "JAPH\n"
718    print "JA" | "  ph\n";                        # prints "japh\n"
719    print "JAPH\nJunk" & "\277\277\277\277\277";  # prints "japh\n";
720    print 'p N$' ^ " E<H\n";                      # prints "Perl\n";
721
722An interesting property of the 32 C0 control characters
723in the ASCII table is that they can "literally" be constructed
724as control characters in perl, e.g. C<(chr(0) eq "\c@")>
725C<(chr(1) eq "\cA")>, and so on.  Perl on EBCDIC machines has been
726ported to take "\c@" to chr(0) and "\cA" to chr(1) as well, but the
727thirty three characters that result depend on which code page you are
728using.  The table below uses the character names from the previous table
729but with substitutions such as s/START OF/S.O./; s/END OF /E.O./;
730s/TRANSMISSION/TRANS./; s/TABULATION/TAB./; s/VERTICAL/VERT./;
731s/HORIZONTAL/HORIZ./; s/DEVICE CONTROL/D.C./; s/SEPARATOR/SEP./;
732s/NEGATIVE ACKNOWLEDGE/NEG. ACK./;.  The POSIX-BC and 1047 sets are
733identical throughout this range and differ from the 0037 set at only
734one spot (21 decimal).  Note that the C<LINE FEED> character
735may be generated by "\cJ" on ASCII machines but by "\cU" on 1047 or POSIX-BC
736machines and cannot be generated as a C<"\c.letter."> control character on
7370037 machines.  Note also that "\c\\" maps to two characters
738not one.
739
740    chr   ord  8859-1               0037                1047 && POSIX-BC
741    ------------------------------------------------------------------------
742    "\c?" 127  <DELETE>             "                   "              ***><
743    "\c@"   0  <NULL>               <NULL>              <NULL>         ***><
744    "\cA"   1  <S.O. HEADING>       <S.O. HEADING>      <S.O. HEADING>
745    "\cB"   2  <S.O. TEXT>          <S.O. TEXT>         <S.O. TEXT>
746    "\cC"   3  <E.O. TEXT>          <E.O. TEXT>         <E.O. TEXT>
747    "\cD"   4  <E.O. TRANS.>        <C1 28>             <C1 28>
748    "\cE"   5  <ENQUIRY>            <HORIZ. TAB.>       <HORIZ. TAB.>
749    "\cF"   6  <ACKNOWLEDGE>        <C1 6>              <C1 6>
750    "\cG"   7  <BELL>               <DELETE>            <DELETE>
751    "\cH"   8  <BACKSPACE>          <C1 23>             <C1 23>
752    "\cI"   9  <HORIZ. TAB.>        <C1 13>             <C1 13>
753    "\cJ"  10  <LINE FEED>          <C1 14>             <C1 14>
754    "\cK"  11  <VERT. TAB.>         <VERT. TAB.>        <VERT. TAB.>
755    "\cL"  12  <FORM FEED>          <FORM FEED>         <FORM FEED>
756    "\cM"  13  <CARRIAGE RETURN>    <CARRIAGE RETURN>   <CARRIAGE RETURN>
757    "\cN"  14  <SHIFT OUT>          <SHIFT OUT>         <SHIFT OUT>
758    "\cO"  15  <SHIFT IN>           <SHIFT IN>          <SHIFT IN>
759    "\cP"  16  <DATA LINK ESCAPE>   <DATA LINK ESCAPE>  <DATA LINK ESCAPE>
760    "\cQ"  17  <D.C. ONE>           <D.C. ONE>          <D.C. ONE>
761    "\cR"  18  <D.C. TWO>           <D.C. TWO>          <D.C. TWO>
762    "\cS"  19  <D.C. THREE>         <D.C. THREE>        <D.C. THREE>
763    "\cT"  20  <D.C. FOUR>          <C1 29>             <C1 29>
764    "\cU"  21  <NEG. ACK.>          <C1 5>              <LINE FEED>    ***
765    "\cV"  22  <SYNCHRONOUS IDLE>   <BACKSPACE>         <BACKSPACE>
766    "\cW"  23  <E.O. TRANS. BLOCK>  <C1 7>              <C1 7>
767    "\cX"  24  <CANCEL>             <CANCEL>            <CANCEL>
768    "\cY"  25  <E.O. MEDIUM>        <E.O. MEDIUM>       <E.O. MEDIUM>
769    "\cZ"  26  <SUBSTITUTE>         <C1 18>             <C1 18>
770    "\c["  27  <ESCAPE>             <C1 15>             <C1 15>
771    "\c\\" 28  <FILE SEP.>\         <FILE SEP.>\        <FILE SEP.>\
772    "\c]"  29  <GROUP SEP.>         <GROUP SEP.>        <GROUP SEP.>
773    "\c^"  30  <RECORD SEP.>        <RECORD SEP.>       <RECORD SEP.>  ***><
774    "\c_"  31  <UNIT SEP.>          <UNIT SEP.>         <UNIT SEP.>    ***><
775
776
777=head1 FUNCTION DIFFERENCES
778
779=over 8
780
781=item chr()
782
783chr() must be given an EBCDIC code number argument to yield a desired
784character return value on an EBCDIC machine.  For example:
785
786    $CAPITAL_LETTER_A = chr(193);
787
788=item ord()
789
790ord() will return EBCDIC code number values on an EBCDIC machine.
791For example:
792
793    $the_number_193 = ord("A");
794
795=item pack()
796
797The c and C templates for pack() are dependent upon character set
798encoding.  Examples of usage on EBCDIC include:
799
800    $foo = pack("CCCC",193,194,195,196);
801    # $foo eq "ABCD"
802    $foo = pack("C4",193,194,195,196);
803    # same thing
804
805    $foo = pack("ccxxcc",193,194,195,196);
806    # $foo eq "AB\0\0CD"
807
808=item print()
809
810One must be careful with scalars and strings that are passed to
811print that contain ASCII encodings.  One common place
812for this to occur is in the output of the MIME type header for
813CGI script writing.  For example, many perl programming guides
814recommend something similar to:
815
816    print "Content-type:\ttext/html\015\012\015\012";
817    # this may be wrong on EBCDIC
818
819Under the IBM OS/390 USS Web Server or WebSphere on z/OS for example
820you should instead write that as:
821
822    print "Content-type:\ttext/html\r\n\r\n"; # OK for DGW et alia
823
824That is because the translation from EBCDIC to ASCII is done
825by the web server in this case (such code will not be appropriate for
826the Macintosh however).  Consult your web server's documentation for
827further details.
828
829=item printf()
830
831The formats that can convert characters to numbers and vice versa
832will be different from their ASCII counterparts when executed
833on an EBCDIC machine.  Examples include:
834
835    printf("%c%c%c",193,194,195);  # prints ABC
836
837=item sort()
838
839EBCDIC sort results may differ from ASCII sort results especially for
840mixed case strings.  This is discussed in more detail below.
841
842=item sprintf()
843
844See the discussion of printf() above.  An example of the use
845of sprintf would be:
846
847    $CAPITAL_LETTER_A = sprintf("%c",193);
848
849=item unpack()
850
851See the discussion of pack() above.
852
853=back
854
855=head1 REGULAR EXPRESSION DIFFERENCES
856
857As of perl 5.005_03 the letter range regular expression such as
858[A-Z] and [a-z] have been especially coded to not pick up gap
859characters.  For example, characters such as E<ocirc> C<o WITH CIRCUMFLEX>
860that lie between I and J would not be matched by the
861regular expression range C</[H-K]/>.  This works in
862the other direction, too, if either of the range end points is
863explicitly numeric: C<[\x89-\x91]> will match C<\x8e>, even
864though C<\x89> is C<i> and C<\x91 > is C<j>, and C<\x8e>
865is a gap character from the alphabetic viewpoint.
866
867If you do want to match the alphabet gap characters in a single octet
868regular expression try matching the hex or octal code such
869as C</\313/> on EBCDIC or C</\364/> on ASCII machines to
870have your regular expression match C<o WITH CIRCUMFLEX>.
871
872Another construct to be wary of is the inappropriate use of hex or
873octal constants in regular expressions.  Consider the following
874set of subs:
875
876    sub is_c0 {
877        my $char = substr(shift,0,1);
878        $char =~ /[\000-\037]/;
879    }
880
881    sub is_print_ascii {
882        my $char = substr(shift,0,1);
883        $char =~ /[\040-\176]/;
884    }
885
886    sub is_delete {
887        my $char = substr(shift,0,1);
888        $char eq "\177";
889    }
890
891    sub is_c1 {
892        my $char = substr(shift,0,1);
893        $char =~ /[\200-\237]/;
894    }
895
896    sub is_latin_1 {
897        my $char = substr(shift,0,1);
898        $char =~ /[\240-\377]/;
899    }
900
901The above would be adequate if the concern was only with numeric code points.
902However, the concern may be with characters rather than code points
903and on an EBCDIC machine it may be desirable for constructs such as
904C<if (is_print_ascii("A")) {print "A is a printable character\n";}> to print
905out the expected message.  One way to represent the above collection
906of character classification subs that is capable of working across the
907four coded character sets discussed in this document is as follows:
908
909    sub Is_c0 {
910        my $char = substr(shift,0,1);
911        if (ord('^')==94)  { # ascii
912            return $char =~ /[\000-\037]/;
913        }
914        if (ord('^')==176) { # 37
915            return $char =~ /[\000-\003\067\055-\057\026\005\045\013-\023\074\075\062\046\030\031\077\047\034-\037]/;
916        }
917        if (ord('^')==95 || ord('^')==106) { # 1047 || posix-bc
918            return $char =~ /[\000-\003\067\055-\057\026\005\025\013-\023\074\075\062\046\030\031\077\047\034-\037]/;
919        }
920    }
921
922    sub Is_print_ascii {
923        my $char = substr(shift,0,1);
924        $char =~ /[ !"\#\$%&'()*+,\-.\/0-9:;<=>?\@A-Z[\\\]^_`a-z{|}~]/;
925    }
926
927    sub Is_delete {
928        my $char = substr(shift,0,1);
929        if (ord('^')==94)  { # ascii
930            return $char eq "\177";
931        }
932        else  {              # ebcdic
933            return $char eq "\007";
934        }
935    }
936
937    sub Is_c1 {
938        my $char = substr(shift,0,1);
939        if (ord('^')==94)  { # ascii
940            return $char =~ /[\200-\237]/;
941        }
942        if (ord('^')==176) { # 37
943            return $char =~ /[\040-\044\025\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/;
944        }
945        if (ord('^')==95)  { # 1047
946            return $char =~ /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\377]/;
947        }
948        if (ord('^')==106) { # posix-bc
949            return $char =~
950              /[\040-\045\006\027\050-\054\011\012\033\060\061\032\063-\066\010\070-\073\040\024\076\137]/;
951        }
952    }
953
954    sub Is_latin_1 {
955        my $char = substr(shift,0,1);
956        if (ord('^')==94)  { # ascii
957            return $char =~ /[\240-\377]/;
958        }
959        if (ord('^')==176) { # 37
960            return $char =~
961              /[\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]/;
962        }
963        if (ord('^')==95)  { # 1047
964            return $char =~
965              /[\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]/;
966        }
967        if (ord('^')==106) { # posix-bc
968            return $char =~
969              /[\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]/;
970        }
971    }
972
973Note however that only the C<Is_ascii_print()> sub is really independent
974of coded character set.  Another way to write C<Is_latin_1()> would be
975to use the characters in the range explicitly:
976
977    sub Is_latin_1 {
978        my $char = substr(shift,0,1);
979        $char =~ /[������������������������������������������������������������������������������������������������]/;
980    }
981
982Although that form may run into trouble in network transit (due to the
983presence of 8 bit characters) or on non ISO-Latin character sets.
984
985=head1 SOCKETS
986
987Most socket programming assumes ASCII character encodings in network
988byte order.  Exceptions can include CGI script writing under a
989host web server where the server may take care of translation for you.
990Most host web servers convert EBCDIC data to ISO-8859-1 or Unicode on
991output.
992
993=head1 SORTING
994
995One big difference between ASCII based character sets and EBCDIC ones
996are the relative positions of upper and lower case letters and the
997letters compared to the digits.  If sorted on an ASCII based machine the
998two letter abbreviation for a physician comes before the two letter
999for drive, that is:
1000
1001    @sorted = sort(qw(Dr. dr.));  # @sorted holds ('Dr.','dr.') on ASCII,
1002                                  # but ('dr.','Dr.') on EBCDIC
1003
1004The property of lower case before uppercase letters in EBCDIC is
1005even carried to the Latin 1 EBCDIC pages such as 0037 and 1047.
1006An example would be that E<Euml> C<E WITH DIAERESIS> (203) comes
1007before E<euml> C<e WITH DIAERESIS> (235) on an ASCII machine, but
1008the latter (83) comes before the former (115) on an EBCDIC machine.
1009(Astute readers will note that the upper case version of E<szlig>
1010C<SMALL LETTER SHARP S> is simply "SS" and that the upper case version of
1011E<yuml> C<y WITH DIAERESIS> is not in the 0..255 range but it is
1012at U+x0178 in Unicode, or C<"\x{178}"> in a Unicode enabled Perl).
1013
1014The sort order will cause differences between results obtained on
1015ASCII machines versus EBCDIC machines.  What follows are some suggestions
1016on how to deal with these differences.
1017
1018=head2 Ignore ASCII vs. EBCDIC sort differences.
1019
1020This is the least computationally expensive strategy.  It may require
1021some user education.
1022
1023=head2 MONO CASE then sort data.
1024
1025In order to minimize the expense of mono casing mixed test try to
1026C<tr///> towards the character set case most employed within the data.
1027If the data are primarily UPPERCASE non Latin 1 then apply tr/[a-z]/[A-Z]/
1028then sort().  If the data are primarily lowercase non Latin 1 then
1029apply tr/[A-Z]/[a-z]/ before sorting.  If the data are primarily UPPERCASE
1030and include Latin-1 characters then apply:
1031
1032    tr/[a-z]/[A-Z]/;
1033    tr/[������������������������������]/[������������������������������]/;
1034    s/�/SS/g;
1035
1036then sort().  Do note however that such Latin-1 manipulation does not
1037address the E<yuml> C<y WITH DIAERESIS> character that will remain at
1038code point 255 on ASCII machines, but 223 on most EBCDIC machines
1039where it will sort to a place less than the EBCDIC numerals.  With a
1040Unicode enabled Perl you might try:
1041
1042    tr/^?/\x{178}/;
1043
1044The strategy of mono casing data before sorting does not preserve the case
1045of the data and may not be acceptable for that reason.
1046
1047=head2 Convert, sort data, then re convert.
1048
1049This is the most expensive proposition that does not employ a network
1050connection.
1051
1052=head2 Perform sorting on one type of machine only.
1053
1054This strategy can employ a network connection.  As such
1055it would be computationally expensive.
1056
1057=head1 TRANSFORMATION FORMATS
1058
1059There are a variety of ways of transforming data with an intra character set
1060mapping that serve a variety of purposes.  Sorting was discussed in the
1061previous section and a few of the other more popular mapping techniques are
1062discussed next.
1063
1064=head2 URL decoding and encoding
1065
1066Note that some URLs have hexadecimal ASCII code points in them in an
1067attempt to overcome character or protocol limitation issues.  For example
1068the tilde character is not on every keyboard hence a URL of the form:
1069
1070    http://www.pvhp.com/~pvhp/
1071
1072may also be expressed as either of:
1073
1074    http://www.pvhp.com/%7Epvhp/
1075
1076    http://www.pvhp.com/%7epvhp/
1077
1078where 7E is the hexadecimal ASCII code point for '~'.  Here is an example
1079of decoding such a URL under CCSID 1047:
1080
1081    $url = 'http://www.pvhp.com/%7Epvhp/';
1082    # this array assumes code page 1047
1083    my @a2e_1047 = (
1084          0,  1,  2,  3, 55, 45, 46, 47, 22,  5, 21, 11, 12, 13, 14, 15,
1085         16, 17, 18, 19, 60, 61, 50, 38, 24, 25, 63, 39, 28, 29, 30, 31,
1086         64, 90,127,123, 91,108, 80,125, 77, 93, 92, 78,107, 96, 75, 97,
1087        240,241,242,243,244,245,246,247,248,249,122, 94, 76,126,110,111,
1088        124,193,194,195,196,197,198,199,200,201,209,210,211,212,213,214,
1089        215,216,217,226,227,228,229,230,231,232,233,173,224,189, 95,109,
1090        121,129,130,131,132,133,134,135,136,137,145,146,147,148,149,150,
1091        151,152,153,162,163,164,165,166,167,168,169,192, 79,208,161,  7,
1092         32, 33, 34, 35, 36, 37,  6, 23, 40, 41, 42, 43, 44,  9, 10, 27,
1093         48, 49, 26, 51, 52, 53, 54,  8, 56, 57, 58, 59,  4, 20, 62,255,
1094         65,170, 74,177,159,178,106,181,187,180,154,138,176,202,175,188,
1095        144,143,234,250,190,160,182,179,157,218,155,139,183,184,185,171,
1096        100,101, 98,102, 99,103,158,104,116,113,114,115,120,117,118,119,
1097        172,105,237,238,235,239,236,191,128,253,254,251,252,186,174, 89,
1098         68, 69, 66, 70, 67, 71,156, 72, 84, 81, 82, 83, 88, 85, 86, 87,
1099        140, 73,205,206,203,207,204,225,112,221,222,219,220,141,142,223
1100    );
1101    $url =~ s/%([0-9a-fA-F]{2})/pack("c",$a2e_1047[hex($1)])/ge;
1102
1103Conversely, here is a partial solution for the task of encoding such
1104a URL under the 1047 code page:
1105
1106    $url = 'http://www.pvhp.com/~pvhp/';
1107    # this array assumes code page 1047
1108    my @e2a_1047 = (
1109          0,  1,  2,  3,156,  9,134,127,151,141,142, 11, 12, 13, 14, 15,
1110         16, 17, 18, 19,157, 10,  8,135, 24, 25,146,143, 28, 29, 30, 31,
1111        128,129,130,131,132,133, 23, 27,136,137,138,139,140,  5,  6,  7,
1112        144,145, 22,147,148,149,150,  4,152,153,154,155, 20, 21,158, 26,
1113         32,160,226,228,224,225,227,229,231,241,162, 46, 60, 40, 43,124,
1114         38,233,234,235,232,237,238,239,236,223, 33, 36, 42, 41, 59, 94,
1115         45, 47,194,196,192,193,195,197,199,209,166, 44, 37, 95, 62, 63,
1116        248,201,202,203,200,205,206,207,204, 96, 58, 35, 64, 39, 61, 34,
1117        216, 97, 98, 99,100,101,102,103,104,105,171,187,240,253,254,177,
1118        176,106,107,108,109,110,111,112,113,114,170,186,230,184,198,164,
1119        181,126,115,116,117,118,119,120,121,122,161,191,208, 91,222,174,
1120        172,163,165,183,169,167,182,188,189,190,221,168,175, 93,180,215,
1121        123, 65, 66, 67, 68, 69, 70, 71, 72, 73,173,244,246,242,243,245,
1122        125, 74, 75, 76, 77, 78, 79, 80, 81, 82,185,251,252,249,250,255,
1123         92,247, 83, 84, 85, 86, 87, 88, 89, 90,178,212,214,210,211,213,
1124         48, 49, 50, 51, 52, 53, 54, 55, 56, 57,179,219,220,217,218,159
1125    );
1126    # The following regular expression does not address the
1127    # mappings for: ('.' => '%2E', '/' => '%2F', ':' => '%3A')
1128    $url =~ s/([\t "#%&\(\),;<=>\?\@\[\\\]^`{|}~])/sprintf("%%%02X",$e2a_1047[ord($1)])/ge;
1129
1130where a more complete solution would split the URL into components
1131and apply a full s/// substitution only to the appropriate parts.
1132
1133In the remaining examples a @e2a or @a2e array may be employed
1134but the assignment will not be shown explicitly.  For code page 1047
1135you could use the @a2e_1047 or @e2a_1047 arrays just shown.
1136
1137=head2 uu encoding and decoding
1138
1139The C<u> template to pack() or unpack() will render EBCDIC data in EBCDIC
1140characters equivalent to their ASCII counterparts.  For example, the
1141following will print "Yes indeed\n" on either an ASCII or EBCDIC computer:
1142
1143    $all_byte_chrs = '';
1144    for (0..255) { $all_byte_chrs .= chr($_); }
1145    $uuencode_byte_chrs = pack('u', $all_byte_chrs);
1146    ($uu = <<'ENDOFHEREDOC') =~ s/^\s*//gm;
1147    M``$"`P0%!@<("0H+#`T.#Q`1$A,4%187&!D:&QP='A\@(2(C)"4F)R@I*BLL
1148    M+2XO,#$R,S0U-C<X.3H[/#T^/T!!0D-$149'2$E*2TQ-3D]045)35%565UA9
1149    M6EM<75Y?8&%B8V1E9F=H:6IK;&UN;W!Q<G-T=79W>'EZ>WQ]?G^`@8*#A(6&
1150    MAXB)BHN,C8Z/D)&2DY25EI>8F9J;G)V>GZ"AHJ.DI::GJ*FJJZRMKJ^PL;*S
1151    MM+6VM[BYNKN\O;Z_P,'"P\3%QL?(R<K+S,W.S]#1TM/4U=;7V-G:V]S=WM_@
1152    ?X>+CY.7FY^CIZNOL[>[O\/'R\_3U]O?X^?K[_/W^_P``
1153    ENDOFHEREDOC
1154    if ($uuencode_byte_chrs eq $uu) {
1155        print "Yes ";
1156    }
1157    $uudecode_byte_chrs = unpack('u', $uuencode_byte_chrs);
1158    if ($uudecode_byte_chrs eq $all_byte_chrs) {
1159        print "indeed\n";
1160    }
1161
1162Here is a very spartan uudecoder that will work on EBCDIC provided
1163that the @e2a array is filled in appropriately:
1164
1165    #!/usr/local/bin/perl
1166    @e2a = ( # this must be filled in
1167           );
1168    $_ = <> until ($mode,$file) = /^begin\s*(\d*)\s*(\S*)/;
1169    open(OUT, "> $file") if $file ne "";
1170    while(<>) {
1171        last if /^end/;
1172        next if /[a-z]/;
1173        next unless int(((($e2a[ord()] - 32 ) & 077) + 2) / 3) ==
1174            int(length() / 4);
1175        print OUT unpack("u", $_);
1176    }
1177    close(OUT);
1178    chmod oct($mode), $file;
1179
1180
1181=head2 Quoted-Printable encoding and decoding
1182
1183On ASCII encoded machines it is possible to strip characters outside of
1184the printable set using:
1185
1186    # This QP encoder works on ASCII only
1187    $qp_string =~ s/([=\x00-\x1F\x80-\xFF])/sprintf("=%02X",ord($1))/ge;
1188
1189Whereas a QP encoder that works on both ASCII and EBCDIC machines
1190would look somewhat like the following (where the EBCDIC branch @e2a
1191array is omitted for brevity):
1192
1193    if (ord('A') == 65) {    # ASCII
1194        $delete = "\x7F";    # ASCII
1195        @e2a = (0 .. 255)    # ASCII to ASCII identity map
1196    }
1197    else {                   # EBCDIC
1198        $delete = "\x07";    # EBCDIC
1199        @e2a =               # EBCDIC to ASCII map (as shown above)
1200    }
1201    $qp_string =~
1202      s/([^ !"\#\$%&'()*+,\-.\/0-9:;<>?\@A-Z[\\\]^_`a-z{|}~$delete])/sprintf("=%02X",$e2a[ord($1)])/ge;
1203
1204(although in production code the substitutions might be done
1205in the EBCDIC branch with the @e2a array and separately in the
1206ASCII branch without the expense of the identity map).
1207
1208Such QP strings can be decoded with:
1209
1210    # This QP decoder is limited to ASCII only
1211    $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr hex $1/ge;
1212    $string =~ s/=[\n\r]+$//;
1213
1214Whereas a QP decoder that works on both ASCII and EBCDIC machines
1215would look somewhat like the following (where the @a2e array is
1216omitted for brevity):
1217
1218    $string =~ s/=([0-9A-Fa-f][0-9A-Fa-f])/chr $a2e[hex $1]/ge;
1219    $string =~ s/=[\n\r]+$//;
1220
1221=head2 Caesarian ciphers
1222
1223The practice of shifting an alphabet one or more characters for encipherment
1224dates back thousands of years and was explicitly detailed by Gaius Julius
1225Caesar in his B<Gallic Wars> text.  A single alphabet shift is sometimes
1226referred to as a rotation and the shift amount is given as a number $n after
1227the string 'rot' or "rot$n".  Rot0 and rot26 would designate identity maps
1228on the 26 letter English version of the Latin alphabet.  Rot13 has the
1229interesting property that alternate subsequent invocations are identity maps
1230(thus rot13 is its own non-trivial inverse in the group of 26 alphabet
1231rotations).  Hence the following is a rot13 encoder and decoder that will
1232work on ASCII and EBCDIC machines:
1233
1234    #!/usr/local/bin/perl
1235
1236    while(<>){
1237        tr/n-za-mN-ZA-M/a-zA-Z/;
1238        print;
1239    }
1240
1241In one-liner form:
1242
1243    perl -ne 'tr/n-za-mN-ZA-M/a-zA-Z/;print'
1244
1245
1246=head1 Hashing order and checksums
1247
1248To the extent that it is possible to write code that depends on
1249hashing order there may be differences between hashes as stored
1250on an ASCII based machine and hashes stored on an EBCDIC based machine.
1251XXX
1252
1253=head1 I18N AND L10N
1254
1255Internationalization(I18N) and localization(L10N) are supported at least
1256in principle even on EBCDIC machines.  The details are system dependent
1257and discussed under the L<perlebcdic/OS ISSUES> section below.
1258
1259=head1 MULTI OCTET CHARACTER SETS
1260
1261Perl may work with an internal UTF-EBCDIC encoding form for wide characters
1262on EBCDIC platforms in a manner analogous to the way that it works with
1263the UTF-8 internal encoding form on ASCII based platforms.
1264
1265Legacy multi byte EBCDIC code pages XXX.
1266
1267=head1 OS ISSUES
1268
1269There may be a few system dependent issues
1270of concern to EBCDIC Perl programmers.
1271
1272=head2 OS/400
1273
1274=over 8
1275
1276=item PASE
1277
1278The PASE environment is runtime environment for OS/400 that can run
1279executables built for PowerPC AIX in OS/400, see L<perlos400>.  PASE
1280is ASCII-based, not EBCDIC-based as the ILE.
1281
1282=item IFS access
1283
1284XXX.
1285
1286=back
1287
1288=head2 OS/390, z/OS
1289
1290Perl runs under Unix Systems Services or USS.
1291
1292=over 8
1293
1294=item chcp
1295
1296B<chcp> is supported as a shell utility for displaying and changing
1297one's code page.  See also L<chcp>.
1298
1299=item dataset access
1300
1301For sequential data set access try:
1302
1303    my @ds_records = `cat //DSNAME`;
1304
1305or:
1306
1307    my @ds_records = `cat //'HLQ.DSNAME'`;
1308
1309See also the OS390::Stdio module on CPAN.
1310
1311=item OS/390, z/OS iconv
1312
1313B<iconv> is supported as both a shell utility and a C RTL routine.
1314See also the iconv(1) and iconv(3) manual pages.
1315
1316=item locales
1317
1318On OS/390 or z/OS see L<locale> for information on locales.  The L10N files
1319are in F</usr/nls/locale>.  $Config{d_setlocale} is 'define' on OS/390
1320or z/OS.
1321
1322=back
1323
1324=head2 VM/ESA?
1325
1326XXX.
1327
1328=head2 POSIX-BC?
1329
1330XXX.
1331
1332=head1 BUGS
1333
1334This pod document contains literal Latin 1 characters and may encounter
1335translation difficulties.  In particular one popular nroff implementation
1336was known to strip accented characters to their unaccented counterparts
1337while attempting to view this document through the B<pod2man> program
1338(for example, you may see a plain C<y> rather than one with a diaeresis
1339as in E<yuml>).  Another nroff truncated the resultant manpage at
1340the first occurrence of 8 bit characters.
1341
1342Not all shells will allow multiple C<-e> string arguments to perl to
1343be concatenated together properly as recipes 0, 2, 4, 5, and 6 might
1344seem to imply.
1345
1346=head1 SEE ALSO
1347
1348L<perllocale>, L<perlfunc>, L<perlunicode>, L<utf8>.
1349
1350=head1 REFERENCES
1351
1352http://anubis.dkuug.dk/i18n/charmaps
1353
1354http://www.unicode.org/
1355
1356http://www.unicode.org/unicode/reports/tr16/
1357
1358http://www.wps.com/texts/codes/
1359B<ASCII: American Standard Code for Information Infiltration> Tom Jennings,
1360September 1999.
1361
1362B<The Unicode Standard, Version 3.0> The Unicode Consortium, Lisa Moore ed.,
1363ISBN 0-201-61633-5, Addison Wesley Developers Press, February 2000.
1364
1365B<CDRA: IBM - Character Data Representation Architecture -
1366Reference and Registry>, IBM SC09-2190-00, December 1996.
1367
1368"Demystifying Character Sets", Andrea Vine, Multilingual Computing
1369& Technology, B<#26 Vol. 10 Issue 4>, August/September 1999;
1370ISSN 1523-0309; Multilingual Computing Inc. Sandpoint ID, USA.
1371
1372B<Codes, Ciphers, and Other Cryptic and Clandestine Communication>
1373Fred B. Wrixon, ISBN 1-57912-040-7, Black Dog & Leventhal Publishers,
13741998.
1375
1376http://www.bobbemer.com/P-BIT.HTM
1377B<IBM - EBCDIC and the P-bit; The biggest Computer Goof Ever> Robert Bemer.
1378
1379=head1 HISTORY
1380
138115 April 2001: added UTF-8 and UTF-EBCDIC to main table, pvhp.
1382
1383=head1 AUTHOR
1384
1385Peter Prymmer pvhp@best.com wrote this in 1999 and 2000
1386with CCSID 0819 and 0037 help from Chris Leach and
1387AndrE<eacute> Pirard A.Pirard@ulg.ac.be as well as POSIX-BC
1388help from Thomas Dorner Thomas.Dorner@start.de.
1389Thanks also to Vickie Cooper, Philip Newton, William Raffloer, and
1390Joe Smith.  Trademarks, registered trademarks, service marks and
1391registered service marks used in this document are the property of
1392their respective owners.
1393
1394
1395