R/CHECKING-check_inchi.R

In NIVANorge/chemspiderapi: R Wrapper for ChemSpider's API Services

.check_inchi <- function(inchi) {
  
  if (is.null(inchi)) {
    stop("No \"inchi\" string provided.", 
         call. = FALSE)
  }
  
  if (!is.character(inchi)) {
    stop("The provided \"inchi\" string is not a character vector.", 
         call. = FALSE)
  }
  
  if (length(inchi) > 1) {
    stop("This function can only handle a single \"inchi\" entry.\nFor functional programming, try using it in apply() or purrr::map().", 
         call. = FALSE)
  }
  
  if (tolower(substr(x = inchi, start = 1L, stop = 6L)) != tolower("InChI=")) {
    stop("This is not a valid \"inchi\" string because \"InChI=\" is missing in the beginning.", 
         call. = FALSE)
  }

  if (tolower(substr(x = inchi, start = 8L, stop = 8L)) != tolower("S")) {
    warning("This is not a standard \"inchi\" string; performing API query regardless.", 
            call. = FALSE)
  }
  
}