[ You asked me to comment on your update. It was a while ago, so I hope this is still useful to you. ]

This sounds like the perfect situation for a dispatch table.

# Setup

my %validators = (
   is_int             => \&is_int,
   is_string          => \&is_string,
   is_yyyy_mm_dd_date => \&is_yyyy_mm_dd_date,
);


# Load configuration

my @validators;
while (<$config_fh>) {                              # Or whatever
   my ($col, $validator_name) = /^col(\d+)=(\w+)$/  #
      or die;

   exists( $validators{$validator_name} )
      or die;
   
   $validators[$col] = $validators{$validator_name};
}


# Process data.

my $csv = Text::CSV->new(sep_char => ';');

while (<$data_fh>) {
   $csv->parse($_)
      or die;

   my @fields = $csv->fields();

   for my $i ( 0..$#validators ) {
      my $validator = $validators[$i];
      next if !defined( $validator );

      $validator->($fields[$i])
         or die;
   }
}
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