diff --git a/inkcpp/functional.cpp b/inkcpp/functional.cpp
index 81289436..5a20067a 100644
--- a/inkcpp/functional.cpp
+++ b/inkcpp/functional.cpp
@@ -9,6 +9,7 @@
 #include "value.h"
 #include "stack.h"
 #include "string_table.h"
+#include "operations.h"
 
 #ifdef INK_ENABLE_UNREAL
 #	include "InkVar.h"
@@ -28,8 +29,28 @@ template<>
 int32_t function_base::pop<int32_t>(basic_eval_stack* stack, list_table& lists)
 {
 	value val = stack->pop();
-	inkAssert(val.type() == value_type::int32, "Type mismatch!");
-	return val.get<value_type::int32>();
+	return casting::numeric_cast<value_type::int32>(val);
+}
+
+template<>
+uint32_t function_base::pop<uint32_t>(basic_eval_stack* stack, list_table& lists)
+{
+	value val = stack->pop();
+	return casting::numeric_cast<value_type::uint32>(val);
+}
+
+template<>
+bool function_base::pop<bool>(basic_eval_stack* stack, list_table& lists)
+{
+	value val = stack->pop();
+	return casting::numeric_cast<value_type::int32>(val) != 0;
+}
+
+template<>
+float function_base::pop<float>(basic_eval_stack* stack, list_table& lists)
+{
+	value val = stack->pop();
+	return casting::numeric_cast<value_type::float32>(val);
 }
 
 template<>
@@ -46,6 +67,24 @@ void function_base::push<int32_t>(basic_eval_stack* stack, const int32_t& v)
 	stack->push(value{}.set<value_type::int32>(v));
 }
 
+template<>
+void function_base::push<uint32_t>(basic_eval_stack* stack, const uint32_t& v)
+{
+	stack->push(value{}.set<value_type::uint32>(v));
+}
+
+template<>
+void function_base::push<float>(basic_eval_stack* stack, const float& v)
+{
+	stack->push(value{}.set<value_type::float32>(v));
+}
+
+template<>
+void function_base::push<bool>(basic_eval_stack* stack, const bool& v)
+{
+	stack->push(value{}.set<value_type::boolean>(v));
+}
+
 void function_base::push_void(basic_eval_stack* stack) { stack->push(values::null); }
 
 void function_base::push_string(basic_eval_stack* stack, const char* dynamic_string)
diff --git a/inkcpp/numeric_operations.h b/inkcpp/numeric_operations.h
index d2593139..0914f401 100644
--- a/inkcpp/numeric_operations.h
+++ b/inkcpp/numeric_operations.h
@@ -88,6 +88,7 @@ namespace casting
 	    numeric_cast<value_type::uint32>(const value& v)
 	{
 		switch (v.type()) {
+			case value_type::int32: return v.get<value_type::int32>();
 			case value_type::uint32: return v.get<value_type::uint32>();
 			/// bool value can cast to uint32
 			case value_type::boolean: return static_cast<uint32_t>(v.get<value_type::boolean>());
diff --git a/inkcpp/output.cpp b/inkcpp/output.cpp
index 6162db2c..06614125 100644
--- a/inkcpp/output.cpp
+++ b/inkcpp/output.cpp
@@ -362,6 +362,7 @@ char* basic_stream::get_alloc(string_table& strings, list_table& lists)
 			case value_type::int32:
 			case value_type::float32:
 			case value_type::uint32:
+			case value_type::boolean:
 				// Convert to string and advance
 				toStr(ptr, end - ptr, _data[i]);
 				while (*ptr != 0)
diff --git a/inkcpp/string_utils.h b/inkcpp/string_utils.h
index 5924af95..c4eeba21 100644
--- a/inkcpp/string_utils.h
+++ b/inkcpp/string_utils.h
@@ -85,18 +85,18 @@ inline int toStr(char* buffer, size_t size, float value)
 	return ec;
 }
 
-inline int toStr(char* buffer, size_t size, const char* c)
+inline int toStr(char* buffer, size_t size, const char* str)
 {
 	char*  ptr = buffer;
 	size_t i   = 0;
-	while (*c && i < size) {
-		*ptr++ = *c;
+	while (i < size && str[i]) {
+		ptr[i] = str[i];
 		++i;
 	}
 	if (i >= size) {
 		return EINVAL;
 	}
-	*ptr = 0;
+	ptr[i] = 0;
 	return 0;
 }
 
@@ -113,7 +113,7 @@ inline int toStr(char* buffer, size_t size, const value& v)
 		case value_type::float32: return toStr(buffer, size, v.get<value_type::float32>());
 		case value_type::boolean: return toStr(buffer, size, v.get<value_type::boolean>());
 		case value_type::newline: return toStr(buffer, size, "\n");
-		default: inkFail("only support toStr for numeric types"); return -1;
+		default: inkFail("No toStr implementation for this type"); return -1;
 	}
 }
 
@@ -148,6 +148,8 @@ inline constexpr size_t value_length(const value& v)
 		case value_type::uint32: return decimal_digits(v.get<value_type::uint32>());
 		case value_type::float32: return decimal_digits(v.get<value_type::float32>());
 		case value_type::string: return c_str_len(v.get<value_type::string>());
+		case value_type::boolean:
+			return v.get<value_type::boolean>() ? c_str_len("true") : c_str_len("false");
 		case value_type::newline: return 1;
 		default: inkFail("Can't determine length of this value type"); return -1;
 	}
diff --git a/inkcpp_test/CMakeLists.txt b/inkcpp_test/CMakeLists.txt
index 2f292f46..1a628535 100644
--- a/inkcpp_test/CMakeLists.txt
+++ b/inkcpp_test/CMakeLists.txt
@@ -17,6 +17,7 @@ add_executable(inkcpp_test catch.hpp Main.cpp
   ThirdTierChoiceAfterBrackets.cpp
   NoEarlyTags.cpp
   ExternalFunctionsExecuteProperly.cpp
+  ExternalFunctionTypes.cpp
   LookaheadSafe.cpp
   EmptyStringForDivert.cpp
   MoveTo.cpp
diff --git a/inkcpp_test/ExternalFunctionTypes.cpp b/inkcpp_test/ExternalFunctionTypes.cpp
new file mode 100644
index 00000000..4c693f5f
--- /dev/null
+++ b/inkcpp_test/ExternalFunctionTypes.cpp
@@ -0,0 +1,48 @@
+#include "catch.hpp"
+
+#include <../runner_impl.h>
+#include <story.h>
+#include <globals.h>
+#include <runner.h>
+#include <compiler.h>
+
+using namespace ink::runtime;
+
+SCENARIO("a story with external functions support types", "[story]")
+{
+	GIVEN("a story with external functions")
+	{
+		auto ink    = story::from_file(INK_TEST_RESOURCE_DIR "ExternalFunctionTypes.bin");
+		auto thread = ink->new_runner().cast<internal::runner_impl>();
+
+		std::stringstream debug;
+		thread->set_debug_enabled(&debug);
+
+		bool         b = false;
+		int          i = 0;
+		unsigned int u = 0;
+		float        f = 0;
+		std::string  s;
+
+		thread->bind("SET_BOOL", [&b](bool o) { b = o; });
+		thread->bind("SET_INT", [&i](int o) { i = o; });
+		thread->bind("SET_UINT", [&u](unsigned int o) { u = o; });
+		thread->bind("SET_FLOAT", [&f](float o) { f = o; });
+		thread->bind("SET_STRING", [&s](std::string o) { s = o; });
+
+		thread->bind("GET_BOOL", [&b]() { return b; });
+		thread->bind("GET_INT", [&i]() { return i; });
+		thread->bind("GET_UINT", [&u]() { return u; });
+		thread->bind("GET_FLOAT", [&f]() { return f; });
+		thread->bind("GET_STRING", [&s]() { return s; });
+
+		WHEN("run thread")
+		{
+			THEN("output shows values from ink")
+			{
+				auto line = thread->getline();
+				REQUIRE(line == "true 1.5 -5 17 foo\n");
+			}
+		}
+	}
+}
diff --git a/inkcpp_test/ink/ExternalFunctionTypes.ink b/inkcpp_test/ink/ExternalFunctionTypes.ink
new file mode 100644
index 00000000..004a13df
--- /dev/null
+++ b/inkcpp_test/ink/ExternalFunctionTypes.ink
@@ -0,0 +1,20 @@
+EXTERNAL GET_BOOL()
+EXTERNAL GET_FLOAT()
+EXTERNAL GET_INT()
+EXTERNAL GET_UINT()
+EXTERNAL GET_STRING()
+EXTERNAL SET_BOOL(b)
+EXTERNAL SET_FLOAT(f)
+EXTERNAL SET_INT(i)
+EXTERNAL SET_UINT(i)
+EXTERNAL SET_STRING(s)
+
+~ SET_BOOL(true)
+~ SET_FLOAT(1.5)
+~ SET_INT(-5)
+~ SET_UINT(17)
+~ SET_STRING("foo")
+
+{GET_BOOL()} {GET_FLOAT()} {GET_INT()} {GET_UINT()} {GET_STRING()}
+
+-> DONE