diff --git a/SLS_C/include/sls/interpreter.h b/SLS_C/include/sls/interpreter.h
index 75ec261..9b3c1d2 100644
--- a/SLS_C/include/sls/interpreter.h
+++ b/SLS_C/include/sls/interpreter.h
@@ -57,7 +57,7 @@ typedef struct {
     HashTable *functions;
 } InterpreterState;
 
-void execute(InterpreterState *interpreter_state, LexerTokenResult *token);
+Boolean execute(InterpreterState *interpreter_state, LexerTokenResult *token);
 InterpreterState *interpreter_create();
 void interpreter_delete(InterpreterState *interpreter_state);
 
diff --git a/SLS_C/src/interpreter.c b/SLS_C/src/interpreter.c
index 3393c6d..a589c78 100644
--- a/SLS_C/src/interpreter.c
+++ b/SLS_C/src/interpreter.c
@@ -3,6 +3,8 @@
 // Interpreter
 // November 2025
 
+#include <stdlib.h>
+
 #include "sls/string.h"
 #include "sls/interpreter.h"
 #include "sls/lexer.h"
@@ -37,8 +39,19 @@ static TokenString *hash_table_get_funcs(const HashTable *ht, SlsStr key, TokenS
     return (TokenString*)hash_table_get(ht, key, (void *)default_item);
 }
 
-void execute(InterpreterState *interpreter_state, LexerTokenResult *token) {
-    
+static Boolean push_token(InterpreterState *interpreter_state, Token token) {
+
+}
+
+static Boolean execute_func(InterpreterState *interpreter_state, SlsStr key) {
+
+}
+
+Boolean execute(InterpreterState *interpreter_state, LexerTokenResult *token) {
+    if (token->result.type == TOKEN_IDENTIFIER && !token->result.identifier.is_literal)
+        return execute_func(interpreter_state, token->result.identifier.name);
+    else
+        return push_token(interpreter_state, token->result);
 }
 
 InterpreterState *interpreter_create() {
diff --git a/SLS_C/src/repl.c b/SLS_C/src/repl.c
index 1245109..fc31b21 100644
--- a/SLS_C/src/repl.c
+++ b/SLS_C/src/repl.c
@@ -49,7 +49,10 @@ int repl(int argc, char *argv[]) {
                     printf("%s\n", head->error.message.str);
                     break;
                 } else
-                    execute(interpreter_state, head);
+                    if (!execute(interpreter_state, head)) {
+                        printf("A runtime error occurred!");
+                        break;
+                    }
                 head = head->next;
             }
             clean_token_result(result.result);