How can I save a coordinate in Cetz?

Questions
4

I see 2 way to solve this:

#import "@preview/cetz:0.3.4"
#cetz.canvas({
  import cetz.draw: *
  let my-coord = (0, 0)
  circle(my-coord)
  line(my-coord, (rel: (1, 2)), mark: (end: ">"))

  circle((5, 5), name: "c")
  line("c", (rel: (1, 2)), mark: (end: ">"))
})

Not sure what you mean by “save a coordinate to a string”.