in reply to Re: Jargon relating to Perl strings
in thread Jargon relating to Perl strings

now $x consists of a single byte.

Yes, that's what I call a byte. So maybe it's my definition, not my term that's unclear.

which is defined in terms of substr, for which the UTF8 flag *does* matter

Ah, there's the problem. "The UTF8 flag doesn't matter" means different things to us. For a given string, substr will always return the same value regardless of the UTF8 flag, so I say the UTF8 doesn't matter to substr. 

my $flag_is_0 = "\xC9ric";  utf8::downgrade($flag_is_0);
my $flag_is_1 = "\xC9ric";  utf8::upgrade($flag_is_1);

say substr($flag_is_0, 0, 1) eq substr($flag_is_1, 0, 1) ?1:0;  # 1

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I shall endeavor to find something clearer.

just do mind that not all people share your definition

Thus this post. If I refer them to this post, they can understand what I say even if their definitions are different.

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Re^3: Jargon relating to Perl strings
by JavaFan (Canon) on Jan 18, 2012 at 09:23 UTC
    Right, we do mean something different with "the UTF-8 doesn't matter". I interpret that as the only difference between the internal representation of the strings is whether the UTF-8 flag is set or not -- but you use it to mean "it doesn't matter whether the internal encoding is UTF-8 or not". 
    use Devel::Peek;

my $x = my $y = "\xC9ric";

utf8::upgrade($x);
utf8::upgrade($y); utf8::encode($y);

Dump($x);
Dump($y);

# Now $x and $y differ only in the setting of the UTF-8 flag

say substr($x, 0, 1) eq substr($y, 0, 1) ? "equal" : "different";

__END__
SV = PV(0x8cd80cc) at 0x8cea9ec
  REFCNT = 1
  FLAGS = (PADMY,POK,pPOK,UTF8)
  PV = 0x8cef6e8 "\303\211ric"\0 [UTF8 "\x{c9}ric"]
  CUR = 5
  LEN = 9
SV = PV(0x8cd803c) at 0x8ceaa28
  REFCNT = 1
  FLAGS = (PADMY,POK,pPOK)
  PV = 0x8cf38b8 "\303\211ric"\0
  CUR = 5
  LEN = 9
different

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[d/l]
      This has already been addressed in the OP, in case you didn't notice.
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