In nacnudus/lexl: Tokenise 'Excel' Formulas

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

lexl separates Excel formulas into tokens of different types, and gives their depth within a nested formula. Its name is a bad pun on 'Excel' and 'lexer'. Try the online demo or run demo_lexl() locally.

Example

library(lexl)
x <- lex_xl("MIN(3,MAX(2,A1))")
x

plot(x) # Requires the ggraph package

Parse tree

Not all parse trees are the same. The one given by lex_xl() is intended for analysis, rather than for computation. Examples of the kind of analysis that it might support are:

Detecting constants that have been embedded inside formulas, rather than in cells referred to by formulas.
Revealing which functions and combinations of functions are most common.
Untangling the dependencies between cells in a spreadsheet.