Re-filing this as an individual request from SERVER-2362, focusing only on $unshift.

I would like to see $unshift implemented simply as an alias to $push with $position: 0, but without requiring $each, because it doesn't read super intuitively:

Before:

$push: {
    scores: {
        $each: [ 50, 60, 70 ],
        $position: 0
    }
}

After:

$unshift: {
    scores: [ 50, 60, 70 ]
}

Much cleaner.

Use cases

There are at least four questions on StackOverflow asking how to insert elements at the beginning of an array:

1. http://stackoverflow.com/questions/7936019/how-do-i-add-a-value-to-the-top-of-an-array-in-mongodb
2. http://stackoverflow.com/questions/13649010/add-values-to-the-beginning-of-an-array-with-mongodb
3. http://stackoverflow.com/questions/10094573/use-mongodb-array-as-stack
4. http://stackoverflow.com/questions/10131957/can-you-have-mongo-push-prepend-instead-of-append