025 quantity div dims

// std/quantity: 10 m / 4 s = 2.5 m/s — dims subtract.
import std/io
import std/quantity

std/quantity:lit { 10 m }
| exact a |> std/quantity:lit { 4 s }
    | exact b |> std/quantity:div(a, b, prec: 20)
        | exact r |> std/quantity:render(n: r): t |> std/io:print.ln("{{ t:s }}")
        | div-zero |> std/io:print.ln("divzero")
        | mixed-cov |> std/io:print.ln("mixed-cov")
        | bad x |> std/io:print.ln("{{ x:s }}")
        | sym-unc |> std/io:print.ln("sym-unc")
    | bad x |> std/io:print.ln("bad")
| bad y |> std/io:print.ln("bad")