feat: improve error message for functions needs feature flags

R/error_conversion.R

@@ -132,3 +132,37 @@ raw_result = function(expr) {
     }
   )
 }
+
+
+#' Check Rust feature flag
+#'
+#' Raise error if the feature is not enabled
+#' @noRd
+#' @param feature_name name of feature to check
+#' @inheritParams unwrap
+#' @return TRUE invisibly if the feature is enabled
+#' @keywords internal
+#' @examples
+#' tryCatch(
+#'   check_feature("simd", "in example"),
+#'   error = \(e) cat(as.character(e))
+#' )
+#' tryCatch(
+#'   check_feature("rpolars_debug_print", "in example"),
+#'   error = \(e) cat(as.character(e))
+#' )
+check_feature = function(feature_name, context = NULL, call = sys.call(1L)) {
+  if (!pl$polars_info()$features[[feature_name]]) {
+    paste0(
+      "\nFeature '", feature_name, "' is not enabled.\n",
+      "Please check the documentation about installation\n",
+      "and re-install with the the feature enabled.\n"
+    ) |>
+      where_in(context) |>
+      when_calling(call) |>
+      to_condition() |>
+      stop()
+  }
+
+  invisible(TRUE)
+}

R/expr__string.R

@@ -188,6 +188,8 @@ ExprStr_to_lowercase = function() {
 #'   tryCatch(f(), error = as.character)
 #' }
 ExprStr_to_titlecase = function() {
+  check_feature("full_features", "in $to_titlecase():")
+
   .pr$Expr$str_to_titlecase(self) |>
     unwrap("in $to_titlecase():")
 }

R/sql.R

@@ -36,6 +36,8 @@ RPolarsSQLContext
 #' ctx = pl$SQLContext(mtcars = mtcars)
 #' ctx
 pl$SQLContext = function(...) {
+  check_feature("sql", "in $SQLContext()")
+
   self = .pr$RPolarsSQLContext$new()
   lazyframes = list(...)