Escapes LaTeX reserved characters as suggested by https://en.wikibooks.org/wiki/LaTeX/Basics#Reserved_Characters.
# S3 method for character
reserve(
  x,
  target = c("#", "$", "%", "^", "&", "_", "{", "}", "~", "\\"),
  replacement = c("\\#", "\\$", "\\%", "\\^{}", "\\&", "\\_", "\\{",
    "\\}", "\\~{}", "\\textbackslash{}"),
  ...
)character
sequence to find (regular expression unless fixed is false)
sequence to use
passed arguments
Other reserve: 
reserve.data.frame(),
reserve.default(),
reserve.factor(),
reserve.list(),
reserve()