$_ = 'alpha="first" beta="second" gamma="third"';

for my $id (qw( alpha beta gamma )) {
    my ($val) = /\b$id=("[^"]*"|\w+)/
        or next;

    print("$id: $val\n");
}

##</code><code>##

alpha: "first"
beta: "second"
gamma: "third"

##</code><code>##

$_ = 'alpha="first" beta="second" gamma="third"';

while (/(\w+)=("[^"]*"|\w+)/g) {
    print("$1: $2\n");
}

##</code><code>##

alpha: "first"
beta: "second"
gamma: "third"