#!/usr/bin/perl -w
use strict;

my $NB_ROWS= 5;
my @FIELDS= qw( name email);

sub process_params
  { my @data;    # stores all the data retrieved as an array of hashes
    foreach my $nb (1..$NB_ROWS)
      { my $row; # stores the data for a single row: field_name => value
        # load the data
        foreach my $type ( @FIELDS) 
          { $row->{$type}= param( "recip$type$nb"); }
        # error check, here just check that all fields are filled or empty
        row_ok( $nb, $row) or return;
        # this is the important part: store row only if values are filled
        push @data, $row if( nb_filled_fields( $row));
      }
    return @data; 
  }

sub row_ok
  { my( $nb, $row)= @_;
    my $nb_fields= nb_filled_fields( $row);
    if( !$nb_fields or $nb_fields == @FIELDS)
      { return 1; }
    else
      { warn "bad data in row $nb";
        return 0;
      }
  }

# count the number of fields that have true values
# you would need to use defined $_ in the grep
# if 0 is a valid value for one of the parameters
sub nb_filled_fields
  { my( $row)= @_;
    my @filled_fields= grep { $_ } values %$row;
    my $nb_filled_fields= @filled_fields;
    return $nb_filled_fields;
  }
        
# main test and smoke and mirror subs

my $test_nb=1;
while( read_params())
  { print "test $test_nb:\n";
    my @data=process_params(); 
    display_data( @data);
    $test_nb++;
  }

sub display_data
  { my @data= @_;
    foreach my $i (0..$#data)
      { print "data[$i]: ";
        foreach my $field (@FIELDS)
          { print " $field => $data[$i]->{$field}"; }
        print "\n";
      }
    print "\n";
  }

{ my $params;

    # just a hack to simulate CGI's param method
    sub read_params
      { $params={}; # reset params

        local $/="\n\n";
        my $data=<DATA>;
        return undef unless $data;
    
        $data=~ s{[ \t]*\#.*\n}{}g; # remove comments
    
        my @rows= split /\n/, $data;
        foreach my $row (@rows)
          { my( $nb, $name, $email)= split /\s*:\s*/, $row;
            $params->{$nb}= { name => $name, email => $email };
          }
        return 1;
      }    

    sub param
      { my( $param_name)= @_; 
        if( $param_name=~ m{^recip(name|email)(\d+)$})
          { my( $type, $nb)= ($1, $2);
            return $params->{$nb}->{$type};
          }
        else
          { die "wrong param called: $param_name"; }
      }
}

__DATA__
# test 1
1 : Andrew : andrew@andrew.com
2 : Joseph : joseph@joseph.com
3
4
5

# test 2 - line 4 should appear as line 2
1 : Andrew :andrew@andrew.com
2
3
4 : Joseph : joseph@joseph.com
5

# test 3 - line 4 should appear as line 1
1
2
3
4 : Joseph : joseph@joseph.com
5

# test 4 - should output warning
1
2
3 :        : dummy@dummy.com
4 : Joseph :	
5