diff --git a/pilang.cpp b/pilang.cpp
index ee6894f..7be8da1 100644
--- a/pilang.cpp
+++ b/pilang.cpp
@@ -37,7 +37,7 @@ namespace Pilang3 {
             bool newarg = false;
             bool escapenext = false;
             std::string cache;
-            for (auto characterit = expression.begin() + tspaces; characterit != expression.end(); characterit++) {
+            for (auto characterit = expression.begin() + tspaces; characterit < expression.end(); characterit++) {
                 char character = *characterit;
                 // Start new command name
                 if (in_command_name) {
@@ -160,6 +160,9 @@ namespace Pilang3 {
                             thisfunc->evalChain.push_back(evaluation);
                             // Skip over expression in iteration
                             character = *(characterit += evaluation->exprlen + 1);
+                            if (characterit == expression.end()) {
+                                throw exceptions::UnexpectedEndOfExpression();
+                            }
                         }
                         character = *(++characterit);
                         thisarg.data = thisfunc;