From d72b758c597e2ecf85632804e0322cb0196af6a4 Mon Sep 17 00:00:00 2001
From: vaclavt <vt@stocksriddle.com>
Date: Sat, 22 Jan 2022 23:03:13 +0100
Subject: [PATCH] handling nil fix

---
 ml.cpp        | 4 ++--
 ml_string.cpp | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/ml.cpp b/ml.cpp
index e87a4fb..343e326 100644
--- a/ml.cpp
+++ b/ml.cpp
@@ -197,7 +197,7 @@ bool MlValue::is_list() const {
 }
 
 bool MlValue::as_bool() const {
-	return type != NIL;
+	return !(type == NIL || (type == LIST && list.empty()));
 }
 
 long MlValue::as_int() const {
@@ -949,7 +949,7 @@ MlValue if_then_else(std::vector<MlValue> args, MlEnvironment &env) {
 	else if (args.size() == 3)
 		return args[2].eval(env);
 
-	return MlValue(0l);
+	return MlValue::nil();
 }
 
 // cond (SPECIAL FORM), in lisp it's macro, but we don't have support for macros yet
diff --git a/ml_string.cpp b/ml_string.cpp
index f8abab3..d4add77 100644
--- a/ml_string.cpp
+++ b/ml_string.cpp
@@ -30,7 +30,6 @@ bool regexp_search(const std::string &where, const std::string &regex_str) {
 		// for (size_t i = 0; i < match.size(); ++i)
 		// 	std::cout << i << ": " << match[i] << '\n';
 		// std::cout << "Suffix: '" << match.suffix() << "\'\n\n";
-
 		return true;
 	}
 	return false;