diff --git a/vignettes/support.R b/vignettes/support.R
new file mode 100644
index 00000000..54d08c4f
--- /dev/null
+++ b/vignettes/support.R
@@ -0,0 +1,13 @@
+knitr::opts_chunk$set(
+  error = FALSE,
+  collapse = TRUE,
+  comment = "#>",
+  fig.width = 7,
+  fig.height = 5)
+
+lang_output <- function(x, lang) {
+  cat(c(sprintf("```%s", lang), x, "```"), sep = "\n")
+}
+cc_output <- function(x) lang_output(x, "cc")
+r_output <- function(x) lang_output(x, "r")
+plain_output <- function(x) lang_output(x, "plain")