Add length() for progressor objects [#188]

Author: HenrikBengtsson

DESCRIPTION

@@ -1,5 +1,5 @@
 Package: progressr
-Version: 0.17.0-9002
+Version: 0.17.0-9003
 Title: An Inclusive, Unifying API for Progress Updates
 Description: A minimal, unifying API for scripts and packages to report progress updates from anywhere including when using parallel processing.  The package is designed such that the developer can to focus on what progress should be reported on without having to worry about how to present it.  The end user has full control of how, where, and when to render these progress updates, e.g. in the terminal using utils::txtProgressBar(), cli::cli_progress_bar(), in a graphical user interface using utils::winProgressBar(), tcltk::tkProgressBar() or shiny::withProgress(), via the speakers using beepr::beep(), or on a file system via the size of a file. Anyone can add additional, customized, progression handlers. The 'progressr' package uses R's condition framework for signaling progress updated. Because of this, progress can be reported from almost anywhere in R, e.g. from classical for and while loops, from map-reduce API:s like the lapply() family of functions, 'purrr', 'plyr', and 'foreach'. It will also work with parallel processing via the 'future' framework, e.g. future.apply::future_lapply(), furrr::future_map(), and 'foreach' with 'doFuture'. The package is compatible with Shiny applications.
 Authors@R: c(person("Henrik", "Bengtsson",

NAMESPACE

@@ -1,6 +1,7 @@
 # Generated by roxygen2: do not edit by hand
 
 S3method(conditionMessage,progression)
+S3method(length,progressor)
 S3method(print,progression)
 S3method(print,progression_handler)
 S3method(print,progressor)

NEWS.md

@@ -1,11 +1,17 @@
 # Version (development version)
 
+## New Features
+
+ * Add `length()` for `progressor` objects, which enables using
+   `seq_along()` and `seq()` on progressors.
+
 ## Bug Fixes
 
  * It was not possible to create more than one progressor in a
    `with_progress()` call, resulting in additional progressors being
-   ignored and warnings on "with_progress() received a progression
-   'initiate' request" being produced.
+   ignored. Also, warnings on "with_progress() received a progression
+   'initiate' request" were produced with **progressr** 0.17.0
+   (2025-10-15).
 
 
 # Version 0.17.0 [2025-10-15]

R/progressor.R

@@ -211,6 +211,12 @@ print.progressor <- function(x, ...) {
 }
 
 
+#' @export
+length.progressor <- function(x) {
+  environment(x)[["steps"]]
+}
+
+
 progressr_in_globalenv <- local({
   state <- FALSE