Update callback.R with keyword arguments (#3430)

see #3390. Also added isTRUE for some of the logical checks, please advise if this is okay

R-package/R/callback.R

@@ -80,7 +80,7 @@ cb.reset.parameters <- function(new_params) {
 
     # Check if rounds is null
     if (is.null(nrounds)) {
-      init(env)
+      init(env = env)
     }
 
     # Store iteration
@@ -95,7 +95,7 @@ cb.reset.parameters <- function(new_params) {
     })
 
     if (!is.null(env$model)) {
-      env$model$reset_parameter(pars)
+      env$model$reset_parameter(params = pars)
     }
 
   }
@@ -141,12 +141,12 @@ merge.eval.string <- function(env) {
 
     # Store evaluation error
     eval_err <- NULL
-    if (is_eval_err) {
+    if (isTRUE(is_eval_err)) {
       eval_err <- env$eval_err_list[[j]]
     }
 
     # Set error message
-    msg <- c(msg, format.eval.string(env$eval_list[[j]], eval_err))
+    msg <- c(msg, format.eval.string(eval_res = env$eval_list[[j]], eval_err = eval_err))
 
   }
 
@@ -169,11 +169,11 @@ cb.print.evaluation <- function(period = 1L) {
       if ((i - 1L) %% period == 0L || is.element(i, c(env$begin_iteration, env$end_iteration))) {
 
         # Merge evaluation string
-        msg <- merge.eval.string(env)
+        msg <- merge.eval.string(env = env)
 
         # Check if message is existing
         if (nchar(msg) > 0L) {
-          cat(merge.eval.string(env), "\n")
+          cat(merge.eval.string(env = env), "\n")
         }
 
       }
@@ -233,7 +233,7 @@ cb.record.evaluation <- function() {
       # Get evaluation data
       eval_res <- env$eval_list[[j]]
       eval_err <- NULL
-      if (is_eval_err) {
+      if (isTRUE(is_eval_err)) {
         eval_err <- env$eval_err_list[[j]]
       }
 
@@ -342,7 +342,7 @@ cb.early.stop <- function(stopping_rounds, first_metric_only = FALSE, verbose =
 
           # Prepare to print if verbose
           if (verbose) {
-            best_msg[[i]] <<- as.character(merge.eval.string(env))
+            best_msg[[i]] <<- as.character(merge.eval.string(env = env))
           }
 
         } else {
@@ -409,7 +409,7 @@ add.cb <- function(cb_list, cb) {
   cb_list <- c(cb_list, cb)
 
   # Set names of elements
-  names(cb_list) <- callback.names(cb_list)
+  names(cb_list) <- callback.names(cb_list = cb_list)
 
   # Check for existence
   if ("cb.early.stop" %in% names(cb_list)) {