diff --git a/R/from_knitr.R b/R/from_knitr.R
new file mode 100644
index 0000000..f782a19
--- /dev/null
+++ b/R/from_knitr.R
@@ -0,0 +1,25 @@
+# These functions are imported from knitr/highr as `:::` is not recommended by
+# CRAN
+
+#' escape special LaTeX characters
+#' @author Yihui Xie
+escape_latex <- function(x, newlines = FALSE, spaces = FALSE) {
+  x = gsub('\\\\', '\\\\textbackslash', x)
+  x = gsub('([#$%&_{}])', '\\\\\\1', x)
+  x = gsub('\\\\textbackslash', '\\\\textbackslash{}', x)
+  x = gsub('~', '\\\\textasciitilde{}', x)
+  x = gsub('\\^', '\\\\textasciicircum{}', x)
+  if (newlines) x = gsub('(?<!\n)\n(?!\n)', '\\\\\\\\', x, perl = TRUE)
+  if (spaces) x = gsub('  ', '\\\\ \\\\ ', x)
+  x
+}
+
+#' escape special HTML characters
+#' @author Yihui Xie
+escape_html <- function(x) {
+  x = gsub('&', '&amp;', x)
+  x = gsub('<', '&lt;', x)
+  x = gsub('>', '&gt;', x)
+  x = gsub('"', '&quot;', x)
+  x
+}