added docs for xtable
diff --git a/R/column_spec.R b/R/column_spec.R
index 71a4b22..693bc80 100644
--- a/R/column_spec.R
+++ b/R/column_spec.R
@@ -216,7 +216,8 @@
     message("Usually it is recommended to use column_spec before collapse_rows,",
             " especially in LaTeX, to get a desired result. ")
   }
-  align_collapse <- ifelse(table_info$booktabs, "", "\\|")
+  align_collapse <- ifelse(table_info$booktabs | !is.null(table_info$xtable),
+                           "", "\\|")
   kable_align_old <- paste(table_info$align_vector, collapse = align_collapse)
 
   table_info$align_vector[column] <- unlist(lapply(
diff --git a/R/xtable2kable.R b/R/xtable2kable.R
index 862d7a1..3c13658 100644
--- a/R/xtable2kable.R
+++ b/R/xtable2kable.R
@@ -51,6 +51,7 @@
   if ("tabular.environment" %in% names(xtable_print_options)) {
     out_meta$tabular <- xtable_print_options$tabular.environment
   }
+  out_meta$xtable <- TRUE
   attr(out, "kable_meta") <- out_meta
   return(out)
 }