in reply to Re^2: Match full utf-8 characters
in thread Match full utf-8 characters

...Although, I find this works when I collect user input with the construct: 
my $user_input = <STDIN>;

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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() ) {
}

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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?

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Re^4: Match full utf-8 characters
by Anonymous Monk on Apr 29, 2019 at 13:55 UTC

    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)

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    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)

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      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.

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        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.

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