Re: Convert the hexadecimal character code to the corresponding Unicode value.

[Emanuel Berg via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

Hongyi Zhao wrote:

> I noticed some comments on the escape syntax used by Emacs
> from here [1-2]. By default, the `describe-char' command
> will give the code point representation of the character in
> hexadecimal and octal formats, say, #o240, #xa0. So, I want
> to if there is a convenient way to do the conversion between
> the hexadecimal character code representation and the
> corresponding Unicode value.

Leads us to the greatest of all human aspirations:

  https://www.youtube.com/watch?v=xA6DtpRuvSQ

Convert between bases:

#! /bin/zsh
#
# this file:
#   http://user.it.uu.se/~embe8573/conf/.zsh/math
#   https://dataswamp.org/~incal/conf/.zsh/math
#
# [...]

change-base () {
    local from=$1
    local to=$2

    local value=$3

    echo "obase=$to; ibase=$from; $value" | bc
}

# _16 ->
hex2dec () { change-base 16 10 $1 }
hex2oct () { change-base 16  8 $1 }
hex2bin () { change-base 16  2 $1 }

# _10 ->
dec2hex () {
    local dec=$1
    local res
    res=$(change-base    10 16 $dec)
    echo $res:l
}
dec2oct () { change-base 10  8 $1 }
dec2bin () { change-base 10  2 $1 }

# _8 ->
oct2hex () {
    local oct=$1
    local res
    res=$(change-base     8 16 $oct)
    echo $res:l
}
oct2dec () { change-base  8 10 $1 }
oct2bin () { change-base  8  2 $1 }

# _2 ->
bin2hex () {
    local bin=$1
    local res
    res=$(change-base     2 16 $bin)
    echo $res:l
}
bin2dec () { change-base  2 10 $1 }
bin2oct () { change-base  2  8 $1 }

-- 
underground experts united
https://dataswamp.org/~incal