#!/usr/bin/env perl
use 5.018;
use JSON::XS qw( encode_json );

my @lines = <DATA>;

my $current_line = q{};
my $idx          = 0;
while ( $idx <= $#lines ) {
    my $line = $lines[$idx];
    chomp($line);

    if ( $line =~ m{^ \s+ \w+ }x ) {
        $current_line .= $line;
    } else {
        if ($current_line) {
            _process_line($current_line);
        }
        $current_line = $line;
    }
    $idx++;
}
if ($current_line) {
    _process_line($current_line);
}

sub _process_line {
    my ($line) = shift;
    my ( $kwd, @vals ) = split( /\s+/, $line );

    say qq{keyword '$kwd' has }, scalar @vals, qq{ values: },
        encode_json( \@vals );
}

exit 0;

__END__
keyword1 data1 data2 data3
keyword2 data1 data2 data3
    data4 data5
    data6
keyword1 data1 data2 data3 data4
keyword3 data1