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

[Hongyi Zhao <hongyi.zhao@gmail.com>]

On Fri, Oct 1, 2021 at 6:42 PM Emanuel Berg via Users list for the GNU
Emacs text editor <help-gnu-emacs@gnu.org> wrote:
>
> 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 }

See this project which can do base conversion up to 36 easily in Emacs:

https://github.com/AdamNiederer/0xc

But sorry for my inaccurate description. I mean the  "\uxxxx"  or
"\U00xxxxxx" counterpart of the code point represented by
decimal/hexadecimal/octal formats. So the shell script you posted
above is not exactly what I asked.

BTW, why do you use `incar' as your website's main name [1]?

[1] https://dataswamp.org/~incal

HZ