docs + spelling

Author: paleolimbot

r/R/vctr.R

@@ -17,6 +17,30 @@
 
 #' Experimental Arrow encoded arrays as R vectors
 #'
+#' This experimental vctr class allows zero or more Arrow arrays to
+#' present as an R vector without converting them. This is useful for arrays
+#' with types that do not have a non-lossy R equivalent, and helps provide an
+#' intermediary object type where the default conversion is prohibitively
+#' expensive (e.g., a nested list of data frames). These objects will not
+#' survive many vctr transformations; however, they can be sliced without
+#' copying the underlying arrays.
+#'
+#' The nanoarrow_vctr is currently implemented similarly to `factor()`: its
+#' storage type is an `integer()` that is a sequence along the total length
+#' of the vctr and there are attributes that are required to resolve these
+#' indices to an array + offset. Sequences typically have a very compact
+#' representation in recent version of R such that this has a cheap storage
+#' footprint even for large arrays. The attributes are currently:
+#'
+#' - `schema`: The [nanoarrow_schema][as_nanoarrow_schema] shared by each chunk.
+#' - `chunks`: A `list()` of `nanoarrow_array`.
+#' - `offsets`: An `integer()` vector beginning with `0` and followed by the
+#'   cumulative length of each chunk. This allows the chunk index + offset
+#'   to be resolved from a logical index with `log(n)` complexity.
+#'
+#' This implementation is preliminary and may change; however, the result of
+#' `as_nanoarrow_array_stream(some_vctr[begin:end])` should remain stable.
+#'
 #' @param x An object that works with [as_nanoarrow_array_stream()].
 #' @param subclass An optional subclass of nanoarrow_vctr to prepend to the
 #'   final class name.

r/man/as_nanoarrow_vctr.Rd

@@ -311,7 +311,7 @@ SEXP nanoarrow_materialize_finalize_result(SEXP converter_xptr, SEXP result) {
     SEXP chunks_tail_sym = PROTECT(Rf_install("chunks_tail"));
     Rf_setAttrib(result, chunks_tail_sym, R_NilValue);
 
-    // We also want to pass on the class of the ptype we recieved
+    // We also want to pass on the class of the ptype we received
     SEXP subclass_sexp = Rf_getAttrib(result, R_ClassSymbol);
 
     // We no longer need the first element of the pairlist, which was