Pig latin translator

pig_latin.R

library(stringr)
library(purrr)

vowels <- c("a", "e", "i", "o", "u")
is_vowel <- function(l) l %in% c(vowels, toupper(vowels))
is_capitalized <- . %>% substr(1, 1) %>% str_detect("[[:upper:]]")
split_at <- function(x, i) split(x, cumsum(seq_along(x) %in% i))

pigify_word <- function(word) {
  ltrs <- strsplit(word, "")[[1]]
  first_vowel <- detect_index(ltrs, is_vowel)
  split_at(ltrs, first_vowel) %>% 
    rev() %>% 
    flatten_chr() %>% 
    c("a", "y") %>% 
    paste(collapse = "")
}

word_apply <- function(text, f, ...) {
  words <- str_split(text, "\\b")[[1]]
  capitalized_words <- map_lgl(words, is_capitalized) %>% which()
  words %>% 
    map_if(~str_detect(., "\\w"), f, ...) %>% 
    map_at(capitalized_words, stringi::stri_trans_totitle) %>% 
    paste(collapse = "")
}

url("http://history.eserver.org/gettysburg-address.txt") %>% 
  readLines() %>% 
  .[4:26] %>% 
  paste(collapse = "") %>% 
  word_apply(pigify_word) %>% 
  strwrap(60) %>% 
  cat(sep = "\n")