diff --git a/src/cli/REPL.cpp b/src/cli/REPL.cpp
index 4d8d805..2048853 100644
--- a/src/cli/REPL.cpp
+++ b/src/cli/REPL.cpp
@@ -27,7 +27,7 @@ void REPL::readInput() {
   char* input;
   string accumulatedInput;
 
-  rl_pre_input_hook = prefillIndentation;
+  rl_pre_input_hook = preInputHook;
 
   while ((input = readline(getPrompt().c_str())) != nullptr) {
     accumulatedInput += string(input);
@@ -77,14 +77,12 @@ void REPL::execute(string source) {
   Compiler::getInstance().clearExceptions();
 }
 
-int REPL::prefillIndentation(const char *text, int count) {
+void REPL::prefillIndentation() {
   string indents(delimeterStack.size() * 2, ' ');
 
   rl_insert_text(indents.c_str());
   rl_point = rl_end;
   rl_redisplay();
- 
-  return 0;
 }
 
 string REPL::getPrompt() { 
diff --git a/src/cli/REPL.hpp b/src/cli/REPL.hpp
index 97352b3..c76442d 100644
--- a/src/cli/REPL.hpp
+++ b/src/cli/REPL.hpp
@@ -13,7 +13,19 @@ namespace Theta {
 
     void readInput();
     
-    static int prefillIndentation(const char *text, int count);
+    #ifdef __APPLE__
+    static int preInputHook(const char *text, int count) {
+      prefillIndentation();
+      return 0;
+    }
+    #else
+    static int preInputHook() {
+      prefillIndentation();
+      return 0;
+    }
+    #endif
+
+    static void prefillIndentation();
 
   private:
     static stack<char> delimeterStack;