hex(3trf)                                                                                                                                hex(3trf)

NAME

       hex - Encoding "hex"

SYNOPSIS

       package require Tcl  ?8.2?

       package require Trf  ?2.1.3?

       hex ?options...? ?data?

DESCRIPTION

       The command hex is one of several data encodings provided by the package trf. See trf-intro for an overview of the whole package.

       This  encoding  transforms  every  byte in the input into a sequence of 2 characters containing the hexadecimal representation of the byte.
       For example

            % hex -mode encode Z
            5A

       hex ?options...? ?data?

              -mode encode|decode
                     This option has to be present and is always understood by the encoding.

                     For immediate mode the argument value specifies the operation to use.  For an attached encoding it specifies the operation to
                     use  for  writing.  Reading will automatically use the reverse operation.  See section IMMEDIATE versus ATTACHED for explana-
                     tions of these two terms.

                     Beyond the argument values listed above all unique abbreviations are recognized too.

                     Encode converts from arbitrary (most likely binary) data into the described representation, decode does the reverse .

              -attach channel
                     The presence/absence of this option determines the main operation mode of the transformation.

                     If present the transformation will be stacked onto the channel whose handle was given to the option and run in attached mode.
                     More about this in section IMMEDIATE versus ATTACHED.

                     If  the option is absent the transformation is used in immediate mode and the options listed below are recognized. More about
                     this in section IMMEDIATE versus ATTACHED.

              -in channel
                     This options is legal if and only if the transformation is used in immediate mode. It provides the handle of the channel  the
                     data to transform has to be read from.

                     If  the  transformation is in immediate mode and this option is absent the data to transform is expected as the last argument
                     to the transformation.

              -out channel
                     This options is legal if and only if the transformation is used in immediate mode. It provides the handle of the channel  the
                     generated transformation result is written to.

                     If the transformation is in immediate mode and this option is absent the generated data is returned as the result of the com-
                     mand itself.

IMMEDIATE VERSUS ATTACHED

       The transformation distinguishes between two main ways of using it. These are the immediate and attached operation modes.

       For the attached mode the option -attach is used to associate the transformation with an existing channel. During the execution of the com-
       mand  no  transformation  is performed, instead the channel is changed in such a way, that from then on all data written to or read from it
       passes through the transformation and is modified by it according to the definition above.  This attachment can be revoked by executing the
       command unstack for the chosen channel. This is the only way to do this at the Tcl level.

       In  the second mode, which can be detected by the absence of option -attach, the transformation immediately takes data from either its com-
       mandline or a channel, transforms it, and returns the result either as result of the command, or writes it into a  channel.   The  mode  is
       named after the immediate nature of its execution.

       Where  the  data  is taken from, and delivered to, is governed by the presence and absence of the options -in and -out.  It should be noted
       that this ability to immediately read from and/or write to a channel is an historic artifact which was introduced at the beginning of Trf's
       life  when  Tcl  version 7.6 was current as this and earlier versions have trouble to deal with  characters embedded into either input or
       output.

SEE ALSO

       ascii85, base64, bin, hex, oct, otp_words, quoted-printable, trf-intro, uuencode

KEYWORDS

       bin, encoding, hex, oct

COPYRIGHT

       Copyright (c) 1996-2003, Andreas Kupries <andreas_kupries@users.sourceforge.net>

Trf transformer commands                                               2.1.3                                                             hex(3trf)