Unify the types of built-in and custom word lists.

Fixes #15

src/main.rs

@@ -95,23 +95,16 @@ fn main() -> Result<(), String> {
         return Err(error_msg.to_string());
     }
 
-    // We need two different variables here, one for a user-inputted list and another for
-    // the built-in list (whether chosen or the default). This is because we use different
-    // variable types for each case.
-    let (custom_list, built_in_list) = match opt.custom_list_file_path {
-        Some(custom_list_file_path) => (Some(read_in_custom_list(&custom_list_file_path)?), None),
-        None => (None, Some(fetch_list(opt.list_choice))),
+    match &opt.custom_list_file_path {
+        Some(custom_list_file_path) => generate_passphrases(&opt, &read_in_custom_list(custom_list_file_path)?),
+        None => generate_passphrases(&opt, fetch_list(opt.list_choice)),
     };
 
-    // If a "custom_list" was given by the user, we're going to use that list.
-    // Otherwise we use the built-in list (a default list if the user didn't choose one).
+    Ok(())
+}
 
-    // To get the length of the list we're going to use, we need to check if a
-    // custom_list was given.
-    let list_length = match custom_list {
-        Some(ref custom_list) => custom_list.len(),
-        None => built_in_list.unwrap().len(), // pretty sure we're safe to unwrap here...
-    };
+fn generate_passphrases<T: AsRef<str> + std::fmt::Display>(opt: &Args, word_list: &[T]) {
+    let list_length = word_list.len();
 
     // Since user can define a minimum entropy, we might have to do a little math to
     // figure out how many words we need to include in this passphrase.
@@ -135,26 +128,14 @@ fn main() -> Result<(), String> {
 
     // Now we can (finally) generate and print some number of passphrases
     for _ in 0..opt.n_passphrases {
-        // Again, we have more code than we should because of this pesky list type situation...
-        let passphrase = match (&custom_list, built_in_list) {
-            (Some(ref custom_list), _) => generate_passphrase(
-                number_of_words_to_put_in_passphrase,
-                &opt.separator,
-                opt.title_case,
-                custom_list,
-            ),
-            (None, Some(built_in_list)) => generate_passphrase(
-                number_of_words_to_put_in_passphrase,
-                &opt.separator,
-                opt.title_case,
-                built_in_list,
-            ),
-            (None, None) => return Err("List selection error!".to_string()),
-        };
+        let passphrase = generate_passphrase(
+            number_of_words_to_put_in_passphrase,
+            &opt.separator,
+            opt.title_case,
+            word_list,
+        );
         println!("{}", passphrase);
-    }
-
-    Ok(())
+    };
 }
 
 /// Print the calculated (estimated) entropy of a passphrase, based on three variables