Running examples in 'khroma-Ex.R' failed
The error most likely occurred in:

> ### Name: scale_colour_stratigraphy
> ### Title: Geologic Timescale Colour Scheme for ggplot2
> ### Aliases: scale_colour_stratigraphy scale_color_stratigraphy
> ###   scale_fill_stratigraphy
> 
> ### ** Examples
> 
> library(ggplot2)
> 
> strati <- data.frame(
+   name = c("Phanerozoic", "Paleozoic", "Cambrian", "Ordovician", "Silurian",
+            "Devonian", "Carboniferous", "Mesozoic", "Triassic", "Cretaceous",
+            "Jurassic", "Cenozoic", "Paleogene", "Neogene", "Quaternary"),
+   type = c("Eon", "Era", "Period", "Period", "Period", "Period", "Period",
+            "Era", "Period", "Period", "Period", "Era", "Period", "Period",
+            "Period"),
+   start = c(541, 541, 541, 485, 444, 419, 359,
+             252, 252, 201, 145, 66, 66, 23, 2.6),
+   end = c(0, 252, 485, 444, 419, 359, 252,
+           66, 201, 145, 66, 2.6, 23, 2.6, 0)
+ )
> 
> ggplot(strati, aes(fill = name)) +
+   geom_rect(aes(xmin = rep(0, 15), xmax = rep(1, 15),
+                 ymin = start, ymax = end)) +
+   scale_y_reverse() + facet_grid(.~type) +
+   scale_fill_stratigraphy(name = "Stratigraphy")
Error in namespaceExport(ns, exports) : 
  undefined exports: %s!=%, %s!==%, %s+%, %s<%, %s<=%, %s==%, %s===%, %s>%, %s>=%, %stri!=%, %stri!==%, %stri+%, %stri<%, %stri<=%, %stri==%, %stri===%, %stri>%, %stri>=%, stri_datetime_add<-, stri_sub<-, stri_subset<-, stri_subset_charclass<-, stri_subset_coll<-, stri_subset_fixed<-, stri_subset_regex<-, stri_c, stri_c_list, stri_cmp, stri_cmp_eq, stri_cmp_equiv, stri_cmp_ge, stri_cmp_gt, stri_cmp_le, stri_cmp_lt, stri_cmp_neq, stri_cmp_nequiv, stri_compare, stri_conv, stri_count, stri_count_boundaries, stri_count_charclass, stri_count_coll, stri_count_fixed, stri_count_regex, stri_count_words, stri_datetime_add, stri_datetime_create, stri_datetime_fields, stri_datetime_format, stri_datetime_fstr, stri_datetime_now, stri_datetime_parse, stri_datetime_symbols, stri_detect, stri_detect_charclass, stri_detect_coll, stri_detect_fixed, stri_detect_regex, stri_dup, stri_duplicated, stri_duplicated_any, stri_enc_detect, stri_enc_detect2, stri_enc_fromutf32, stri_enc_get, stri_enc_inf
Calls: <Anonymous> ... tryCatch -> tryCatchList -> tryCatchOne -> <Anonymous>
Execution halted