Bind mbox_df class

R/globals.R

@@ -0,0 +1 @@
+utils::globalVariables(c("num_discussants", "subject"))

R/merge_mbox_all.R

@@ -61,6 +61,7 @@ merge_mbox_all <-
         }
       }
 
+class(multi_mbox) <- c("mbox_df", class(multi_mbox))
       return(multi_mbox)
     } else {
       stop("No mbox file is found in the current directory.")

R/preprocessing.R

@@ -2,8 +2,12 @@
 #' @export
 
 # Remove carriage return and trim white spaces in subject line
-trim_subject <- function(df) {
-df %>%
+trim_subject <- function(mbox_df) {
+if(!inherits(mbox_df, "mbox_df")) {
+stop("You need an mbox_df object for this function: Convert your mbox file through `read_mbox()` first.")
+}
+
+mbox_df %>%
 dplyr::mutate(subject = stringr::str_replace_all(string = subject, pattern = "[[:cntrl:]]+", replacement = " ")) %>%
 dplyr::mutate(subject = stringr::str_replace_all(string = subject, pattern = "[[:space:]]+", replacement = " "))
 }

R/read_mbox.R

@@ -86,5 +86,6 @@ read_mbox <-
         warning("Something is wrong with your output file name. Currently only 'RDS' format is supported.")
       }
     }
+    class(df) <- c("mbox_df", class(df))
     return(df)
   } # Function ends.

R/thread.R

@@ -30,6 +30,10 @@
 #' @author Soyoung Choi, \email{[email protected]}
 
 num_thread <- function(mbox_df) {
+if(!inherits(mbox_df, "mbox_df")) {
+stop("You need an mbox_df object for this function: Convert your mbox file through `read_mbox()` first.")
+}
+
   mbox_df %>%
 is_thread() %>%
 sum(., na.rm = TRUE)
@@ -40,6 +44,9 @@ sum(., na.rm = TRUE)
 #' @export
 
 is_thread <- function(mbox_df) {
-  #  checkMbox_df(mbox_df)["num_discussants"] > 1
+if(!inherits(mbox_df, "mbox_df")) {
+stop("You need an mbox_df object for this function: Convert your mbox file through `read_mbox()` first.")
+}
+
   mbox_df$num_discussants > 1
 }