perlebcdic.pod

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    <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:

=over 4

=item recipe 4

=back

    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:

=over 4

=item recipe 5

=back

    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:

=over 4

=item recipe 6

=back

    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


=head1 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 C<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 machines
from either a CCSID 0037, a 1047, or a POSIX-BC EBCDIC machine 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 machine) the second C<$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';

=head1 CONVERSIONS

=head2 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 C<$cp_1047> table.  The fourth column of the output from recipe
0 could provide a C<$cp_posix_bc> table suitable for transcoding as well.

=head2 iconv

XPG operability often implies the presence of an I<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.

=head2 C RTL

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

=head1 OPERATOR DIFFERENCES

The C<..> range operator treats certain character ranges with 
care on EBCDIC machines.  For example the following array
will have twenty six elements on either an EBCDIC machine
or an ASCII machine:

    @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 machine than when run on an ASCII machine.  Here is
an example adapted from the one in L<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. C<(chr(0) eq "\c@")> 
C<(chr(1) eq "\cA")>, and so on.  Perl on EBCDIC machines 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 C<LINE FEED> character
may be generated by "\cJ" on ASCII machines but by "\cU" on 1047 or POSIX-BC