Do Programmers have a sense of humour?

Why yes they do! Is it too arcane for anyone else to be able to determine? Maybe. Here are some funny puzzles from a great post and a long list of comments. Can you guess what the idiom, song or movie is?

// idiom 3

injury += insult;

// idiom 6

a = getThickness('blood');
b = getThickness('water');
assert(a > b);

// idiom 9

prey = 'worm';
time = getCurrentTime();
if (time >= 4 && time <= 8) {
   bird.catch(prey);
}

// idiom 19
return way.my || way.high;

// idiom from comments

if (!fire) {
   smoke = null;
}

// song 1
sleep = false;
gogo();

// song 3;
var tiger[i];

// song 5
var it = now || never;

// song 10
compare(null, u);

// song 14
person.name = 'jude';
person.greet();

// song 16
var s1 = 'tutti';
var s2 = s1.replace('tu', 'fru');
print(s1 + ' ' + s2);

// song 20
var country = new Array('UK', 'Italy', 'USA', 'Spain');
giveBirth(country[2]);

// movie 1
while (i < infinity) {
   tomorrow = dies;
   i++;
}

// movie 2
int numerator = 1;
int denominator = 0;
int mission = numerator / denominator;