#stop condition is the first empty line.

use strict;
use warnings;

sub mapInEval {
  my $content = shift;
  my @lines;

  my $result;
  eval {
     # leaves eval loop, not sub
     @lines = map { /^$/ ? return : $_ } split /\n/, $content;
     return 1;
  };
  print "non empty lines: <@lines>\n";
}

sub mapNotInEval {
  my $content = shift;
  my @lines;

  my $result;
  # leaves the sub !!!!
  @lines = map { /^$/ ? return : $_ } split /\n/, $content;

  print "non empty lines: <@lines>\n";
}

my $spacey = <<__EOF__;
Do

Re
Mi
__EOF__

my $notSpacey = <<__EOF__;
A
B
C
__EOF__

print "WITH eval { ... } around map\n";
print "testing spacy: ";
mapInEval($spacey);
print "\ntesting not spacy:";
mapInEval($notSpacey);

print "------------------------------\n";
print "WITHOUT eval { ... } around map\n";
print "testing spacy: ";
mapNotInEval($spacey);
print "\ntesting not spacy:";
mapNotInEval($notSpacey);