diff --git a/R/check.r b/R/check.r
new file mode 100644
index 0000000..64f6071
--- /dev/null
+++ b/R/check.r
@@ -0,0 +1,20 @@
+#' @name check model
+#' @title Check model and produce messages/warnings if any problems
+#'
+#' @description
+#' This function currently only checks for balanced braces.
+#' @param x a \code{\link{stanedit}} object
+#' @importFrom checkmate assert_class
+#' @return invisible \code{x} (called for it's side effects)
+#' @seealso \code{\link{stanedit}}
+#' @keywords internal
+check_model <- function(x) {
+  x <- assert_class(x, "stanedit")
+  ## check
+  opening_curls <- length(grep("\\{", x))
+  closing_curls <- length(grep("\\}", x))
+  if (opening_curls != closing_curls) {
+    warning("Model contains unbalanced braces.")
+  }
+  return(invisible(x))
+}
diff --git a/R/clean.r b/R/clean.r
index abadbe0..7ad9fca 100644
--- a/R/clean.r
+++ b/R/clean.r
@@ -42,9 +42,8 @@ clean_model <- function(x) {
         x[i] <- sub("/\\*.*$", "", x[i])
         comment <- TRUE
       }
-      if (!grepl("[{};][[:space:]]*$", x[i]) &&
-          !(grepl("#", x[i])) &&
-          i < length(x)) {
+      if (!grepl("[{};][[:space:]]*$", x[i]) && !(grepl("#", x[i])) &&
+            i < length(x)) {
         ## line not finished -- merge lines
         x[i] <- paste(x[i], x[i + 1])
         x <- x[-(i + 1)]
@@ -71,13 +70,7 @@ clean_model <- function(x) {
   ## remove empty lines
   x <- x[x != ""]
 
-  ## check
-  opening_curls <- length(grep("\\{", x))
-  closing_curls <- length(grep("\\}", x))
-  if (opening_curls != closing_curls) {
-    warning("Model contains unbalanced braces.")
-  }
   model <- structure(x, class = "stanedit")
 
-  return(model)
+  return(check_model(model))
 }
diff --git a/man/check-model.Rd b/man/check-model.Rd
new file mode 100644
index 0000000..c287b51
--- /dev/null
+++ b/man/check-model.Rd
@@ -0,0 +1,22 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/check.r
+\name{check model}
+\alias{check model}
+\alias{check_model}
+\title{Check model and produce messages/warnings if any problems}
+\usage{
+check_model(x)
+}
+\arguments{
+\item{x}{a \code{\link{stanedit}} object}
+}
+\value{
+invisible \code{x} (called for it's side effects)
+}
+\description{
+This function currently only checks for balanced braces.
+}
+\seealso{
+\code{\link{stanedit}}
+}
+\keyword{internal}