Exciting things I learned at rstudio::conf(2022)

Quarto

```{r}
!4 %in% c(4, 5, 1)
```

[1] FALSE

```{julia}
4 ∉ [4, 5, 1]
```

false

```{python}
4 not in [4, 5, 1]
```

False

Unification

• Languages

  quarto preview notebook.ipynb --to pdf
  quarto convert notebook.ipynb # to .qmd

• Platforms

Simplification

• Flexible engines: Knitr, Jupyter, and Observable
• Easy transition: .Rmd → .qmd
• RStudio IDE Visual Editor
  • Easy editing/formatting of Markdown tables
  • Copy/paste from Google docs
  • Citation (Allaire 2022)
  • Insert anything: ⌘/

The Posit future

• Carlos Rios will need to change all of his RSConnect, Workbench, Package Manager slides 😈
• More features for Python, Julia, etc.
  • Shiny for Python
  • The language-agnostic Quarto engine
  • WASM: code on a browser with WebR
• Terrible puns: positive, deposit 🤦🏽

New ways to build Shiny apps

• gridlayout: layout complex dashboards, built on CSS grid
• shinyuieditor: a drag-and-drop visual editor for your Shiny app’s ui
• Dashboard-Builder: generate even server’s code

shinytest2: game changer!

• record_test()

test_that("{shinytest2} recording: simple-app", {
  app <- AppDriver$new(name = "simple-app", height = 407, width = 348)
  app$set_inputs(name = "Barret")
  app$click("greet")
  app$expect_values()
})

• app$view()

• shiny::exportTestValue()

Other neat talks

• WASM WebR, Emscripten
• geoarrow
• tidysynthesis
• Kelly O’Briant’s Off-Host Content Execution for Posit Connect
• diffify
• Alice Walsh’s Becoming Creative

Package development masterclass

• Tests: test code != regular code
  • everything inside a testthat() chunk
• Documentation: useful != exactly correct
  • @param x,y
  • @keywords internal

Write better error messages

• Consistent
• Transparent: type, value
• Relevant: which function failed, for which argument
• Exhaustive: contextual information, external resources
• Concise: avoid paragraphs of text
• expect_snapshot()

Error bullets

cli::cli_abort(c(
  "My error message.",
  "*" = "Bullet",
  "i" = "Info bullet",
  "x" = "Cross bullet",
  "v" = "Check bullet"
))

Error:
! My error message.
• Bullet
ℹ Info bullet
✖ Cross bullet
✔ Check bullet

Function design

• rlang::arg_match(): more about argument than match, autocomplete, etc.

• cli_inform()

Other workshops

• Shiny in production
• What they forgot to teach you about R
• Art from Code
• nbdev + Quarto

References

Allaire, JJ. 2022. “Quarto: R Interface to ’Quarto’ Markdown Publishing System.” https://CRAN.R-project.org/package=quarto.

Thank you!