Comment by velcrovan

HTML (and XMLish syntax in general) is LISP syntax (not semantics) in disguise. A tag can be viewed as function application, with the attributes as named arguments and the elements as variadic arguments.

The example from the link's main page is equivalent to:

    (button "Say something")
    (on_click
      (selection-insert-after
        (div "Hello, World ")))

[apparently HN strips all emoji but you get the idea]