tex-parser

tex-parser-footnote.R

parse2 <- function(x) {
  # x <- "ab{c{f}}d{e}f{g}h{ij{{k}}}lm"
  x_split <- unlist(strsplit(x, "", fixed = TRUE))
  tex_group <- cumsum(x_split == "{") - cumsum(x_split == "}")
  max_tex_group <- max(tex_group)
  out <- setDT(list(char = x_split, tex_group = tex_group))
  
  out[, I := .I]
  
  
  for (j in seq_len(max_tex_group)) {
    tgj <- paste0("tg", j)
    out[tex_group >= j, (tgj) := cumsum(char == "{" & tex_group == j)]
  }
  out
}

footnote_opens <- function(DT) {
  c("\\", "f", "o", "o", "t", "n", "o", "t", "e", "{")
  for (k in 0:9) {
    DT[, (paste0("v", k)) := shift(char, k + 1)]
  }
  
  
  DT %>%
    .[char == "{"] %>%
    .[v0 == "e"] %>%
    .[v1 == "t"] %>%
    .[v2 == "o"] %>%
    .[v3 == "n"] %>%
    .[v4 == "t"] %>%
    .[v5 == "o"] %>%
    .[v6 == "o"] %>%
    .[v7 == "f"] %>%
    .[v8 == "\\"]
}