add Chadwick helper functions

[beanumber]

Getting Chadwick to work on Linux (and probably Mac) requires setting the LD_LIBRARY_PATH environment variable. This process is not well-documented to begin with, and then the use of system() to call cwevent depends on the environment variable being set correctly, which it's not by default. Without this variable set, retrosheet_data() doesn't work.

I wrote these functions to help me debug my own installation, and I think they would be helpful for others. Adding a call to chadwick_ld_library_path() inside retrosheet_data() would hopefully make this work seamlessly for more people.

I'd be happy to work this up into a formal pull request if you'll consider it.

chadwick_installed <- function() {
  out <- fs::path_dir(system2("which", "cwevent", stdout = TRUE))
  if (!fs::dir_exists(out)) {
    stop("Chadwick could not be find.")
  } else {
    return(fs::path(out))
  }
}
chadwick_installed()

chadwick_find_lib <- function() {
  system2(
    "find", 
    '/usr/local -name "libchadwick*"', stdout = TRUE
  ) |>
    dirname() |>
    unique()
}
chadwick_find_lib()

chadwick_set_ld_library_path <- function() {
  new_ld_library_path <- paste(
    chadwick_find_lib(), 
    Sys.getenv("LD_LIBRARY_PATH"), 
    sep = ":"
  )
  Sys.setenv(LD_LIBRARY_PATH = new_ld_library_path)
}

chadwick_ld_library_path <- function() {
  ld_library_paths <- Sys.getenv("LD_LIBRARY_PATH") |>
    stringr::str_split_1(pattern = ":")
  if (!chadwick_find_lib() %in% ld_library_paths) {
    chadwick_set_ld_library_path()
  }
  chadwick_find_lib() %in% ld_library_paths
}
chadwick_ld_library_path()

# 2016 Retrosheet play-by-play data

chadwick_ld_library_path()
retro_data <- baseballr::retrosheet_data(
  here::here("data_large/retrosheet"),
  c(1998, 2016)
)

[saiemgilani]

Yes, please. It was incredibly confusing trying to get this to work