Let's decode it using perl 

perl -MO=Deparse perl_is_simple.pl

print chr hex length ' bless localtime ref ' if length
'aller ve' and print 'P' and print 'e' and print 'r' 
and print 'l' and print ' ' and print 'i' and print 
's' and print ' ' and print 's' and print 'i' and print
'm' and print 'p' and print 'l' and print 'e';

• Compared to the original ...

length q caller vec and print chr oct ord q qx eq and print
chr ord q ref or and print chr ord q or no and print chr ord 
q else and print chr ord qq q q and print chr ord q tie gt 
and print chr ord qw q sin q and print chr ord q q eq and 
print chr ord qw q sin q and print chr ord q sin s and print 
chr ord q cmp lc and print chr ord q split s and print chr 
ord qw q lc q and print chr ord q ne sin and print chr hex 
length q q bless localtime ref q