Checking pairs of vector inputs to an R function to see if the longer of each pair is a multiple of the shorter, emit a dynamic warning if so

check-vector-pairs-multiples.R

pair_inputs <- function(...) {
  
  args <- rlang::dots_list(..., .named = TRUE)
  args_lengths <- lapply(args, length)
  
  pairs <- combn(args_lengths, 2, simplify = FALSE)
  
  failed <- lapply(pairs, function(x) max(unlist(x)) %% min(unlist(x)) != 0)
  
  if (any(unlist(failed))) {
    
    failed_i <- which(unlist(failed))
    failed_pairs <- lapply(pairs[failed_i], unlist)
    
    failed_pasted <- lapply(
      failed_pairs, 
      function(x) {
        x <- sort(x, decreasing = TRUE)
        paste0(
          "{.var ", names(x[1]), "} had length ", x[1],
          " but ", 
          "{.var ", names(x[2]), "} had length ", x[2]
        )
      }
    )
    
    names(failed_pasted) <- rep("*", length(failed_pasted))
    
    cli::cli_warn(
      c(
        i = "Longer object length is not a multiple of shorter object length.",
        i = "Vectors were recycled with some values left over.",
        i = "This occurred because:", 
        unlist(failed_pasted)
      )
    )
    
  }
  
}

pair_inputs(x = 1:2, y = 7:1, z = 1:5, a = 1)