Something interesting is partial application. Say you have a function that takes two arguments:

    add = a b -> a + b

This is really equivalent to:

    add = a -> b -> a + b

Which in turn is equivalent to:

    add = a -> {
        b -> { a + b }
    }

(for good measure). This means that the first call to add, when you pass a value `x`, returns a function (the `b -> { a + b }) that closes over x:

    add_5 = add 5
    add_5 7  -- is 12
    add_5 -1 -- is 4

This also has a unique property: most function calls are just chains of identifiers and values:

    foo bar "Hello" baz

Which means, if we consider them as chains, we can match against those chains and apply transformations to them:

   syntax 'foo 'bar name 'baz { print name }

Which is the basis of Passerine's macro system! (And don't worry, if the form matches multiple macros of if you use an identifier defined in a macro, it'll let you know).

Hope this helps!