Changelog • livelink

livelink 0.1.0

Initial CRAN release. livelink packs R code into a shareable URL that runs in the browser, with no server and nothing to upload. Two destinations are supported: webR, a full R REPL, and Shinylive, which runs R and Python Shiny apps.

Features

webR REPL links

webr_repl_link(): create a shareable link for a single R script.
webr_repl_project(): create a link for a multi-file R project.
webr_repl_exercise(): create paired exercise and solution links, for teaching.
webr_repl_directory(): turn a directory into one link per script, or into a single bundled link with single_link = TRUE.

Shinylive links

shinylive_r_link() and shinylive_py_link(): create a link for an R or Python Shiny app.
shinylive_project(): create a link for a multi-file Shiny app.
shinylive_directory(): create a link for every Shiny app in a directory.

Decoding and preview

decode_webr_link() and decode_shinylive_link(): extract the embedded files to a directory. They default to the session temporary directory, so a stray call cannot litter your project.
preview_webr_link() and preview_shinylive_link(): inspect a link in memory without writing anything, which is the safe way to open a link from someone else.
Decoded results expose the same fields whether a link came from webR or Shinylive, so one piece of code can handle both.

Input flexibility

Code can be an R expression (no quotes or escaping), a character string, a file path, or whatever is on the clipboard.
Multi-file input via named lists or file path vectors. The primary argument is input across every link-creating function, whatever form the code takes.

Configuration

Choose which webR panels appear (plot, files, terminal, editor) with panels, and Shinylive’s editor-or-app view with mode.
autorun runs the code the moment a link opens.
set_webr_base_url(): point webR links at a custom or self-hosted deployment.

Working with the results

Every returned object answers to repl_urls() and as.character() for the bare URL(s), and to format() for its summary as a character vector.
knit_print() renders a link object as a clickable link when it is the value of a ‘knitr’ or ‘Quarto’ chunk.
as.data.frame() turns a directory or a decoded batch into a tidy data frame.

Documents

use_livelink_engine(): registers a livelink chunk engine for ‘knitr’ and ‘Quarto’, so a code chunk in a document becomes a runnable link.
```
```{livelink}
#| autorun: true
# Load the data
data(mtcars)
plot(mtcars$mpg, mtcars$wt)
```
```
Use this rather than expression input inside a knitted document. ‘knitr’ runs chunks through evaluate::evaluate(), which discards source references, so comments inside a { } expression are silently dropped when a document is rendered, and no keep.source setting recovers them. The engine receives the chunk’s verbatim source, so comments survive. Chunk options cover autorun, panels, mode, filename, link.text, link.only, and engine.target ("webr", "shinylive-r", or "shinylive-py").
use_livelink_hook(): a ‘knitr’ chunk hook, so an ordinary r chunk can carry its own link. The chunk still runs, its output and plots appear in the rendered page, and a link is added underneath:
```
```{r}
#| livelink: true
#| autorun: true
data(mtcars)
plot(mtcars$mpg, mtcars$wt)   # a comment that survives
```
```

The engine (```{livelink}) replaces execution, so it produces a link but no R output. The hook is what you want when the reader should see the result and also be able to open it; the engine is for code the session cannot or should not run, such as a Shiny app or anything needing a package you have not installed.

Both are registered on load, and both receive the chunk’s verbatim source, so comments reach the link either way.

Projects as code

webr_repl_project(), shinylive_project(), and shinylive_r_link() accept a file’s contents as a braced expression, so a multi-file project can be written as R rather than as strings full of escaped newlines:
```
webr_repl_project(list(
  "main.R"    = { source("utils.R"); summarise(mtcars) },
  "utils.R"   = { summarise <- function(d) summary(d) },
  "README.md" = "# Analysis"
))
```
The blocks are captured, never evaluated. They are source to ship, not code to run, so an assignment inside one leaves nothing behind in the session. Strings and expressions mix freely, which is what a project holding both code and a README.md needs.

This only works when the list is written inside the call. list() is an ordinary function, so assigning it to a variable first evaluates its arguments and the block runs there and then. livelink detects that case and errors, rather than encoding whatever the block returned.