Question

I am trying to Convert hex representations of Unicode characters to the characters they represent. The following example works fine:

#!/usr/bin/perl

use Encode qw( encode decode );
binmode(STDOUT, ':encoding(utf-8)');

my $encoded = encode('utf8', "\x{e382}\x{af}");
eval { $encoded = decode('utf8', $encoded, Encode::FB_CROAK); 1 }
or print("coaked\n");

print "$encoded\n";

However the hex digits are stored in 3 variables.

So if i replace the encode line with this:

my $encoded = encode('utf8', "\x{${byte1}${byte2}}\x{${byte3}}");

where

my $byte1 = "e3"; my $byte2 = "82"; my $byte3 = "af";

It fails as it tries to evaluate the \x immediately and sees the $ sign and { as characters.

Does anyone know how to get around this.

Answer 1

Instead of

my $encoded = encode('utf8', "\x{${byte1}${byte2}}\x{${byte3}}");

You can use

my $encoded = encode('utf8', chr(hex($byte1 . $byte2)) . chr(hex($byte3)));

hex() converts from hexadecimal, and chr() returns the unicode character for a given code point.

[Edit:]

Not related to your question, but I noticed you mix utf-8 and utf8 in your program. I don’t know if this is a typo, but you should be a ware that these are not the same things in Perl:
utf-8 (with hyphen, case insensitive) is what the UTF-8 standard says, whereas utf8 (no hyphen, also case insensitive) is Perls internal encoding, which is more loosely defined (it allows codepoints that are not valid unicode codepoints). In general, you should stick to utf-8 (perlunifaq has the details).