refactor: ♻️ add internal check_parquet_path (#179)

# Description

For a cleaner flow in `read_register()`.

Needs no review. 

## Checklist

- [X] Ran `just run-all`

Author: signekb

R/read.R

@@ -26,32 +26,47 @@ read_register <- function(
     checkmate::check_file_exists(path),
     checkmate::check_directory_exists(path)
   )
+  check_parquet_path(path)
+
+  # If input path is a directory, read as partitioned Parquet register,
+  # else read as Parquet file.
+  if (fs::is_dir(path)) {
+    read_register_partition(path)
+  } else {
+    read_register_file(path)
+  }
+}
+
+
+#' Check whether path is to a Parquet file or directory with Parquet files.
+#'
+#' @inheritParams read_register
+#'
+#' @returns `path` invisibly.
+#'
+#' @keywords internal
+#' @noRd
+check_parquet_path <- function(path) {
   if (
     fs::is_dir(path) &&
       length(fs::dir_ls(path, regexp = "\\.(parquet|parq)$", recurse = TRUE)) ==
         0
   ) {
-    cli::cli_abort("The path {path} does not contain any Parquet files.")
+    cli::cli_abort(
+      "The path {.path {path}} does not contain any Parquet files."
+    )
   } else if (
     fs::is_file(path) &&
       fs::path_ext(path) != "parquet" &&
       fs::path_ext(path) != "parq"
   ) {
     cli::cli_abort(
-      "The path {path} must have a `.parquet` or `.parq` extension."
+      "The path {.path {path}} must have a {.val .parquet} or {.val .parq} extension."
     )
   }
-
-  # If input path is a directory, read as partitioned Parquet register,
-  # else read as Parquet file.
-  if (fs::is_dir(path)) {
-    read_register_partition(path)
-  } else {
-    read_register_file(path)
-  }
+  invisible(path)
 }
 
-
 #' Read a partitioned Parquet register as DuckDB table
 #'
 #' @param path A character scalar with the path to the Parquet register