[Tcsh] "Readable" Unicode in setenv
H.Merijn Brand
tcsh at tux.freedom.nl
Fri Nov 12 15:46:20 UTC 2021
On Fri, 12 Nov 2021 16:32:42 +0100, "H.Merijn Brand" <tcsh at tux.freedom.nl> wrote:
> If I have an environment variable that is to contain something Unicodish,
> I currently have to to something similar to
>
> % setenv EURO_CH `perl -CO -e'print "\N{EURO SIGN}"'`
> or
> % setenv EURO_CH `perl -CO -e'print "\x{20ac}"'`
>
> so this works
> % echo $EURO_CH
> €
>
> I browsed the tcsh manual, but could not find anything that would hint
> to doing this natively. Is there a (hidden) feature to set Unicode
> characters from the command line by their name or hex value (in the
> current encoding)? Something similar to
>
> % setenv EURO_CH "\x{20ac}"
> % setenv EURO_CH "\u20AC"
>
> In my digging, I found that
>
> % setenv TAB_CH "\t"
>
> just sets the environment variable TAB_CH to a literal '\' followed by
> a 't'. Which was kinda surprising to me, as I expected a TAB to be in
> there as a literal TAB. That was done in echo in sh.func.c, so
>
> % echo $TAB_CH
>
> translated \t to TAB. To do the same for \x{20ac}, \xbf, and \u0020ac
> I changed sh.func.c like below, but I eventually want those escapes
> to end up literally in the environment. Thoughts welcome
>
> --8<---
> diff --git a/sh.func.c b/sh.func.c
> index cdfb6d8d..cbc4ff41 100644
> --- a/sh.func.c
> +++ b/sh.func.c
> @@ -1196,6 +1196,22 @@ doglob(Char **v, struct command *c)
> flush();
> }
>
> +static Char
> +parse_hex_range(Char **cp, int l)
> +{
> + int ui = 0;
> + char ub[9];
> +
> + if (l > 8) return 0; /* Unsupported length */
> +
> + while (**cp && ui < l && isxdigit(**cp)) {
> + ub[ui++] = (char)**cp;
> + (*cp)++;
> + }
> + ub[ui] = (char)0;
> + return strtol (ub, NULL, 16);
> +}
> +
> static void
> xecho(int sep, Char **v)
> {
> @@ -1289,6 +1305,28 @@ xecho(int sep, Char **v)
> if (*cp >= '0' && *cp < '8')
> c = c * 8 + *cp++ - '0';
> break;
> + case 'x':
> + if (*cp == '{' && isxdigit(*(cp + 1))) { /* \x{20ac} */
> + cp++;
> + c = parse_hex_range (&cp, 8);
> + if (*cp != '}')
> + stderror(ERR_NAME | ERR_VARBEGIN);
This needs a proper new error message of course
> + cp++;
> + }
> + else if (isxdigit(*cp)) { /* \x9f */
> + c = parse_hex_range (&cp, 2);
> + }
> + else /* backward compat */
> + xputchar('\\' | QUOTE);
> + break;
> + case 'u':
> + if (isxdigit(*cp)) { /* \u0020ac */
> + c = parse_hex_range (&cp, 6);
> + }
> + else /* backward compat */
> + xputchar('\\' | QUOTE);
> + break;
> +
> case '\0':
> c = '\\';
> cp--;
> -->8---
And a demo of course
% unsetenv EURO
% echo $EURO
EURO: Undefined variable.
% setenv EURO "\u20ac"
% env | grep EURO
EURO=\u20ac
% echo $EURO
€
% setenv EURO `echo "\u20ac"`
% env | grep EURO
EURO=€
% echo $EURO
€
--
H.Merijn Brand https://tux.nl Perl Monger http://amsterdam.pm.org/
using perl5.00307 .. 5.33 porting perl5 on HP-UX, AIX, and Linux
https://tux.nl/email.html http://qa.perl.org https://www.test-smoke.org
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