Further: approaching the question of "what is the difference between list and scalar context, and when are they applied?" via an experiential/experimental approach with wantarray is eminently practical. To wit, here's a simple test script I wrote when I wanted to clarify the matter for myself. This most definitely constitutes Another Way To Do It:
#!/usr/bin/perl -w
sub polymorphic {
my $context=wantarray();
if ($context) {
print "list context\n";
return @_;
} elsif (defined($context)) {
print "scalar context\n";
return join ":", @_;
} else {
warn "value of polymorphic() used in void context. Values were (\n
+";
# so no point in returning anything, but do print
print join ",", @_;
print ")\n";
}
}
sub show_args {
print "got ", scalar(@_), " args:\n";
map {print " $_\n" } @_;
}
show_args("a", polymorphic("b","c","d"));
my $string=polymorphic(1,2,3);
my @array=polymorphic(4,5,6);
show_args($string,@array);
# make warning 1
polymorphic("unused");
# following is tricky because we don't know context until tricky is
# actually called.
sub tricky {
polymorphic(@_);
}
my $string2=tricky(qw(a b c d));
my @array2=tricky(qw(s t u v));
show_args($string2,@array2);
# make warning 2
tricky(qw(fee fi fo fum));
# what happens if we use return keyword explicitly?
sub tricky_2 {
return polymorphic(@_);
}
my $string3=tricky_2(qw(a e i o u));
my @array3=tricky_2(qw(w x y z));
show_args($string3,@array3);
# (turns out we can use return or not; same result--no warning)
# (but this should generate one)
tricky_2(5,6,7,8);
sub tricky_3 {
my $first=shift;
my $second=shift;
my @remaining=@_;
print "$first, $second, (";
print join ",", @remaining;
print ")\n";
};
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