You can even be cleaner: $car is $.car (though this doesn't work for $.$.car). But I don't think this is really a specific case of partial application (though I see where you're coming from). While partial application would be ((map car) '((1 2) (3 4) (5 6))) and this would be ($car '((1 2) (3 4) (5 6))), the biggest win (for me) is not the partial application aspect, but the conciseness of having just one character, as opposed to (currently) ([map car _] '((1 2) (3 4) (5 6))) or ([apply map car __] '((1 2) (3 4) (5 6))), or even the partial application version. And even so, this strikes me as more similar to a request for explicit partial application, which is already implementable, than implicit partial application.
Yes, it was the conciseness I was after. The syntax was inspired by K, where you can do this by putting a ' before a function name.
Of course, K often looks like line noise, but then K takes this technique to its logical conclusion and uses special syntax for everything. There's no need to go that far.
