Follow-up: I did a little legwork and found some Julia folks who were also inspired to implement tidyverse as faithfully as possible: https://github.com/TidierOrg

Here's how dplyr-style chains look in their system:

  using TidierData
  using RDatasets

  movies = dataset("ggplot2", "movies");

  @chain movies begin
      @mutate(Budget = Budget / 1_000_000)
      @filter(Budget >= mean(skipmissing(Budget)))
      @select(Title, Budget)
      @slice(1:5)
  end

Not a character-for-character match to dplyr, but gets much closer than most other attempts!