INTERCAL::Charset::Hollerith(3pm)

NAME
Charset::Hollerith - convert between INTERCAL variant of Hollerith and ASCII

SYNOPSIS
    use Charset::Hollerith qw(hollerith2ascii);

    my $a = hollerith2ascii "(Hollerith text)";

DESCRIPTION
Charset::Hollerith defines functions to convert between a subset of ASCII and a subset of nonstandard Hollerith (since there isn't such a thing as a standard Hollerith we defined our own variant which is guaranteed to be incompatible with all versions of Hollerith used by IBM hardware - however, for each character code we have used the code used by some (but not all) IBM card reader, if the code exists in Hollerith at all, or we have made one up in some logical way (such as overpunching) if no IBM hardware had that particular character.

The two functions hollerith2ascii and ascii2hollerith are exportable but not exported by default. They do the obvious thing to their argument.

HOLLERITH CHARACTER TABLE
A Hollerith string is a sequence of 12-bit characters; they are encoded as two ASCII characters, containing 6 bits each: the first character contains punches 12, 0, 2, 4, 6, 8 and the second character contains punches 11, 1, 3, 5, 7, 9; interleaving the two characters gives the original 12 bits. To make the characters printable on ASCII terminals, bit 7 is always set to 0, and bit 6 is set to the complement of bit 5. These two bits are ignored when reading Hollerith cards.

Some Hollerith characters (produced by overpunching) can be converted to sequences of ASCII characters; ascii2hollerith will correctly recognise the sequences.

The following punched cards document the encoding of characters; the last card ends with nongraphic symbols in ASCII so the column heading contains a two-letter abbreviation instead, and with the two overpunch symbols we use, change and bookworm, whose column heading shows the two characters, "C/" and "V-" respectively:

        ' !"#$%&()*+,-./:;<=>?@[\]^_`{|}~0123456789
   12      *   * * *  *     *    * *   *              12
   11        *    *  *    * **    **  * *             11
    0     *   * *   *  ****    *     *   *             0
    1                  *                  *            1
    2   *  *  *              *             *           2
    3       **      * *                     *          3
    4           ***       * * ** *   * *     *         4
    5          *        *  *          *       *        5
    6                    *        * ** *       *       6
    7     *                    ***      *       *      7
    8   *  ******** * * ******* * * * *          *     8
    9     *                             *         *    9

        ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrs
   12   *********                 *********             12
   11            *********                 *********    11
    0                     *********        *        *    0
    1   *        *                **       **       *    1
    2    *        *       *        **       **      *    2
    3     *        *       *        **       **          3
    4      *        *       *        **       **         4
    5       *        *       *        **       **        5
    6        *        *       *        **       **       6
    7         *        *       *        **       **      7
    8          *        *       *        **       **     8
    9           *        *       *        *        *     9

        tuvwxyz []  ".  NL  CR  HT  C/  V-
   12            *   *   *           *      12
   11                        *           *  11
    0   *******  *               *   *   *   0
    1                    *   *   *   *       1
    2   *                *   *   *           2
    3   **           *   *   *   *   *       3
    4    **      *       *   *   *           4
    5     **             *   *   *       *   5
    6      **            *   *   *           6
    7       **   *   *   *   *   *           7
    8        **      *   *   *   *           8
    9         *          *   *   *           9

PLEASE NOTE that versions of CLC-INTERCAL before 1.-94.-2 had a bug which caused a rabbit to be represented as 12-3-2-8 instead of 12-3-7-8. Cards punched with such older versions, and containing rabbits, will need to be copied with one of the rabbit holes moved from row 2 to row 7.

COPYRIGHT
This module is part of CLC-INTERCAL.

Copyright (C) 2000, 2002, 2006, 2007 Claudio Calvelli, all rights reserved

See the files README and COPYING in the distribution for information.

SEE ALSO
A qualified psychiatrist.