Re^3: Match full utf-8 characters

[Allasso]

...Although, I find this works when I collect user input with the construct:

my $user_input = <STDIN>;

but does not work when I collect it with:

my $stdin = new IO::Handle;
   $stdin->fdopen( fileno( STDIN ), "r" ) || die "Cannot open STDIN";
while ( my $char = $stdin->getc() ) {
}

and I need to use hippo's suggestion below. In each iteration, $char is a byte. Is there a way to coerce $char to be utf8?

[Anonymous Monk]

That's a very convoluted way of achieving something that's already done for you:

$ perl -E'say STDIN->can("getc")'
$ perl -MIO::Handle -E'say STDIN->can("getc")'
CODE(0x55dddd02b150)

I.e. if IO::Handle is loaded, STDIN is already an object resembling IO::Handle and you can call getc method on it.

But for the sake of the exercise, you should be able to pass "<:utf8" instead of "r" to fdopen and have getc return Unicode characterscode points again. (untested)

[Allasso]

You're probably way above my head here, but when using STDIN->can("getc") it does not wait for user input, which is what I am doing with my construct.

Also, attempting to use "<:utf8" instead of "r" gives IO::Handle: bad open mode... error.

I also tried moving binmode(STDIN, ':utf8') call to after opening the filehandle as recommended here: https://perldoc.perl.org/perlfunc.html#binmode-FILEHANDLE%2c-LAYER -- but that did not help.

[Anonymous Monk]

STDIN->can("getc") being defined means that you can call the method: STDIN->getc().

Sorry about giving you misleading information on the "mode" parameter of IO::Handle::fdopen. From my understanding of the documentation (For the documentation of the "open" method, see IO::File. ... If "IO::File::open" is given a mode that includes the ":" character, it passes all the three arguments to the three-argument "open" operator.), it should have worked.

I also tried moving binmode(STDIN, ':utf8') ... but that did not help.

That is because you don't use the STDIN file handle, but create another one with the UTF-8 decoding layer stripped. Try setting ":utf8" binmode on STDIN, then using calling STDIN->getc (or just getc, since STDIN is chosen by default) in a loop.