clean up

inst/tutorials/introduction-to-python/tutorial.Rmd

@@ -17,28 +17,19 @@ description: Tutorial for introducing students to the Python language.
 <!-- Do the test cases need to have all the Python commands? Or does the tutorial magically know that import polars . . . has already been run? -->
 
 <!-- Learn about reticulate. -->
+```{r setup, include=FALSE}
+# -------------------------------------------------------------------
+# Global setup: R packages + Python virtualenv for the tutorial
+# -------------------------------------------------------------------
 
-
-```{r early-env, include=FALSE}
-# Don't let reticulate autoconfigure arbitrary Pythons
+# Don't let reticulate auto-pick some random Python
 Sys.setenv(RETICULATE_AUTOCONFIGURE = "FALSE")
 
-is_windows <- identical(.Platform$OS.type, "windows")
-
-# Point to venv Python only if it exists; use OS-appropriate path
-py_guess <- if (is_windows) ".venv/Scripts/python.exe" else ".venv/bin/python"
-if (file.exists(py_guess)) {
-  Sys.setenv(RETICULATE_PYTHON = normalizePath(py_guess, winslash = "/", mustWork = FALSE))
-}
-
-```
-
-```{r setup, include=FALSE}
 # ---- Safe CRAN mirror + interactive-only installs ----
 if (is.null(getOption("repos")["CRAN"]) || !nzchar(getOption("repos")["CRAN"])) {
   options(repos = c(CRAN = "https://cloud.r-project.org"))
 }
-needed <- c("learnr","tutorial.helpers","knitr","reticulate")
+needed <- c("learnr", "tutorial.helpers", "knitr", "reticulate")
 to_install <- setdiff(needed, rownames(installed.packages()))
 if (interactive() && length(to_install)) {
   install.packages(to_install, quiet = TRUE)
@@ -57,59 +48,42 @@ learnr::tutorial_options(
 
 # ---- Environment flags ----
 is_windows <- identical(.Platform$OS.type, "windows")
-in_ci <- !interactive() || identical(tolower(Sys.getenv("CI")), "true")
-
-# ---- Python/reticulate behavior ----
-if (in_ci) {
-  # Don’t execute Python in CI (render code only)
-  knitr::knit_engines$set(
-    python = function(options) {
-      knitr::engine_output(options, code = options$code,
-                           out = "\n<!-- python execution skipped in CI -->\n")
-    }
-  )
-} else {
-  # Use local venv if present; do not install anything here
-  venv <- ".venv"
-  py_bin <- if (is_windows) file.path(venv, "Scripts", "python.exe") else file.path(venv, "bin", "python")
-  if (file.exists(py_bin)) {
-    Sys.setenv(RETICULATE_PYTHON = normalizePath(py_bin, winslash = "/", mustWork = FALSE))
-    reticulate::use_virtualenv(venv, required = FALSE)
-  }
-  # Enable Python engine (reticulate)
-  knitr::knit_engines$set(python = reticulate::eng_python)
-}
-
-
-```
-
-```{r bootstrap-python-venv, include=FALSE}
-# --- Robust, cross-platform venv bootstrap (works locally, safe on CI) ---
-
-is_windows <- identical(.Platform$OS.type, "windows")
-venv <- ".venv"
-py_bin <- if (is_windows) file.path(venv, "Scripts", "python.exe") else file.path(venv, "bin", "python")
-
-# Detect CI / R CMD check: don't try to build a venv or run Python then.
 in_ci <- identical(tolower(Sys.getenv("CI")), "true") ||
          identical(tolower(Sys.getenv("R_CMD_CHECK")), "true") ||
          !interactive()
 
+venv <- ".venv"
+py_bin <- if (is_windows) file.path(venv, "Scripts", "python.exe") else file.path(venv, "bin", "python")
+
 if (in_ci) {
-  # Render-only: don't execute Python, don't create venv
+  # -----------------------------------------------------------------
+  # CI / R CMD check: render-only, no Python execution or venv setup
+  # -----------------------------------------------------------------
   knitr::knit_engines$set(
     python = function(options) {
-      knitr::engine_output(options, code = options$code,
-                           out = "\n<!-- python execution skipped in CI / R CMD check -->\n")
+      knitr::engine_output(
+        options,
+        code = options$code,
+        out  = "\n<!-- python execution skipped in CI / R CMD check -->\n"
+      )
     }
   )
+
 } else {
-  # 1) Pick a system Python
+  # -----------------------------------------------------------------
+  # Local use: create/activate .venv in this tutorial directory
+  # -----------------------------------------------------------------
+
+  # 1) Find a system Python
   python_exe <- Sys.which(if (is_windows) "python" else "python3")
-  if (!nzchar(python_exe)) python_exe <- reticulate::py_discover_config()$python
-  if (!nzchar(python_exe)) stop("No usable system Python found to create .venv.")
+  if (!nzchar(python_exe)) {
+    python_exe <- reticulate::py_discover_config()$python
+  }
+  if (!nzchar(python_exe)) {
+    stop("No usable system Python found to create .venv.")
+  }
 
-  # 2) Create .venv if missing
+  # 2) Create .venv if missing (do NOT delete if it already exists)
   if (!dir.exists(venv)) {
     message("Creating .venv with: ", python_exe)
     reticulate::virtualenv_create(envname = venv, python = python_exe)
@@ -119,20 +93,23 @@ if (in_ci) {
   Sys.setenv(RETICULATE_PYTHON = normalizePath(py_bin, winslash = "/", mustWork = FALSE))
   reticulate::use_virtualenv(venv, required = TRUE)
 
-  # 4) Upgrade pip tooling (use python -m pip to avoid OS-specific pip paths)
-  system2(py_bin, c("-m", "pip", "install", "--upgrade", "pip", "setuptools", "wheel"),
-         stdout = TRUE, stderr = TRUE)
+  # 4) Upgrade pip tooling via `python -m pip` (portable, no pip.exe assumption)
+  system2(
+    py_bin,
+    c("-m", "pip", "install", "--upgrade", "pip", "setuptools", "wheel"),
+    stdout = TRUE,
+    stderr = TRUE
+  )
 
-  # 5) Install required packages (again via python -m pip)
+  # 5) Install required Python packages into this .venv
   req <- c("polars", "pandas", "numpy", "plotnine", "matplotlib", "seaborn")
   system2(py_bin, c("-m", "pip", "install", req), stdout = TRUE, stderr = TRUE)
 
-  # 6) Ensure knitr uses reticulate's Python engine
+  # 6) Tell knitr to use reticulate's Python engine
   knitr::knit_engines$set(python = reticulate::eng_python)
 }
 ```
 
-
 ```{r copy-code-chunk, child = system.file("child_documents/copy_button.Rmd", package = "tutorial.helpers")}
 ```