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Code-generation server

Source: R/app_module_code.R
ie_code_server.Rd

A central module that assembles "idealized example code" for an isoexplorer app and shows it in a viewer. It is instantiated once at the top level; every other module that can contribute code returns a get_code() generator, and the top-level wiring registers each one here with register() under an id, a heading, and (optionally) the id it depends_on.

Usage

ie_code_server(id, get_active_group = reactive(NULL))

ie_code_ui(id)

Arguments

id

the module id (namespace); pair with ie_code_ui() on the same id

get_active_group

a reactive returning the active group id; only registrations in this group (plus group-less ones) are shown. The default reactive(NULL) shows everything.

Value

the code handle: a list with register(code_id, heading, get_code, depends_on = NULL, group = NULL) (each depends_on is a single id – the tree is single-parent) and build_document(quarto = FALSE) (assemble + return list(script, headings); exposed mainly for testing).

Details

The registrations form a dependency tree. When the user clicks the navbar Show code button (ie_code_ui()), the registered generators are walked depth-first and assembled into one document: the tree depth sets the heading level (# for a root such as a read step, ## for a step depending on a root, ### for one depending on that, ...), and each step's output variable is threaded in as the input_var of the steps that depend on it. The document is shown in a read-only shinyAce::aceEditor() with a clickable headings tree (jump-to-section), a toggle between plain code and a Quarto view, and a .qmd download.

Each registration may carry a group; when get_active_group() returns a non-empty value only registrations in that group (plus group-less ones) are shown – the full multi-tab app uses this to show just the active measurement type's code.

Functions

  • ie_code_ui(): the navbar Show code button (place in the navbar, e.g. bslib::nav_item(ie_code_ui("code"))) plus the one-time JS used to jump the editor to a heading. Pair with ie_code_server() on the same id.

The get_code() contract

a registered generator is function(input_var = NULL) returning list(code = <string>, output = <string or NULL>). It is called during assembly inside a reactive context, so it reflects the module's current state; input_var is the output variable of the module it depends on (NULL for a root), and output is the variable this snippet binds (or NULL for a terminal node such as a plot).

Examples

if (interactive()) {
  library(shiny)
  # ie_run_app() instantiates the code server for you; here it is wired
  # directly. Register each module's get_code generator into the dependency
  # tree; the "Show code" button (ie_code_ui()) assembles and displays it.
  ui <- bslib::page_fillable(ie_code_ui("code"))
  server <- function(input, output, session) {
    code <- ie_code_server("code")
    code$register("read", "Read data files", get_code = function(input_var = NULL) {
      list(
        code = 'iso <- ir_find_scans("data") |> ir_read_isofiles()',
        output = "iso"
      )
    })
    code$register("agg", "Aggregate data files", depends_on = "read",
      get_code = function(input_var = NULL) {
        list(
          code = sprintf("scans <- %s |> ir_aggregate_isofiles()", input_var),
          output = "scans"
        )
      })
  }
  shinyApp(ui, server)
}