use strict;
use warnings;
use Switch;

for ('abc', 'def', 'ghi')
{
    switch ()
    {
        case /bc/ { print "$_: matches 'bc'\n"; }
        case /de/ { print "$_: matches 'de'\n"; }
        case ''   { print "EMPTY STRING\n"; }
        else      { print "$_: no match found\n"; }
    }
}

##</code><code>##

 1:51 >perl 1675_SoPW.pl
EMPTY STRING
EMPTY STRING
EMPTY STRING

 1:51 >

##</code><code>##

MAIN_LOOP: while (<READ_NETLIST>) {
    chomp;
    s/^\s+//;       # Remove leading blanks (if any) in the line
    # ignore line if it contains comments or initializing words for spectre
    switch ($_) {
        case /^[*\/]/i           { next MAIN_LOOP; }
        case /simulator\s+lang/i { next MAIN_LOOP; }
        case /^include/i         { next MAIN_LOOP; }
    }
    ...
}