From 009218c6f954ca10f87ad2703f9afe86a23cabaf Mon Sep 17 00:00:00 2001
From: Stepan Usatiuk <stepus53@gmail.com>
Date: Wed, 3 Jan 2024 21:59:40 +0100
Subject: [PATCH] error on unknown function

---
 src/vm/src/Compiler.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/vm/src/Compiler.cpp b/src/vm/src/Compiler.cpp
index 12cb2d5..9bf2db1 100644
--- a/src/vm/src/Compiler.cpp
+++ b/src/vm/src/Compiler.cpp
@@ -7,6 +7,7 @@
 
 #include <functional>
 #include <stack>
+#include <stdexcept>
 #include <string>
 
 #include "Command.h"
@@ -131,6 +132,7 @@ Handle Compiler::compile(const Handle &src, Handle fake_env, const Handle &suffi
 
                 out.append(make_cmd(LD));
                 Handle idx = findIndex(car, fake_env);
+                if (idx.null()) throw std::invalid_argument("Could not find function to apply: " + std::string(car.strval()));
                 out.append(idx);
                 out.append(make_cmd(AP));
             }