I prefer the best of both worlds. I've been making a YAML like widget syntax in code using an immediate mode GUI written in Nim. It let's me write things like:

    Horizontal:
      box 10.WPerc, 100, 8.Em, 2.Em

      Button:
        text: fmt"Clicked4: {self.count:4d}"
        setup: size 8.Em, 2.Em
        onClick: self.count.inc()

https://github.com/elcritch/fidget/blob/devel/tests/basicwid...