From b74f3448b2253997efbdbd5c1a169bc3ce1bb75f Mon Sep 17 00:00:00 2001
From: Riyyi <riyyi3@gmail.com>
Date: Sun, 5 Nov 2023 14:30:24 +0100
Subject: [PATCH] Eval: Allow multiple s-expr in fn*

---
 lisp/init.bl              |  4 ++--
 src/eval-special-form.cpp | 22 ++++++++++++++++------
 src/eval.cpp              |  2 +-
 3 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/lisp/init.bl b/lisp/init.bl
index 993c140..3067c64 100644
--- a/lisp/init.bl
+++ b/lisp/init.bl
@@ -1,10 +1,10 @@
 
 (defmacro! defmacro
   (fn* [name args & body]
-    `(defmacro! ~name (fn* ~args (do ~@body)))))
+    `(defmacro! ~name (fn* ~args ~@body))))
 
 (defmacro defn [name args & body]
-  `(def! ~name (fn* ~args (do ~@body))))
+  `(def! ~name (fn* ~args ~@body)))
 
 (defmacro def [name & body]
   `(def! ~name ~@body))
diff --git a/src/eval-special-form.cpp b/src/eval-special-form.cpp
index 60ee18e..98a1728 100644
--- a/src/eval-special-form.cpp
+++ b/src/eval-special-form.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include <iterator> // std::next, std::prev
+#include <iterator> // std::distance, std::next, std::prev
 #include <list>
 #include <memory>
 #include <span>
@@ -70,7 +70,7 @@ ValuePtr Eval::evalDefMacro(const ValueVector& nodes, EnvironmentPtr env)
 // (fn* (x) x)
 ValuePtr Eval::evalFn(const ValueVector& nodes, EnvironmentPtr env)
 {
-	CHECK_ARG_COUNT_IS("fn*", nodes.size(), 2);
+	CHECK_ARG_COUNT_AT_LEAST("fn*", nodes.size(), 2);
 
 	// First element needs to be a List or Vector
 	VALUE_CAST(collection, Collection, nodes.front());
@@ -84,8 +84,18 @@ ValuePtr Eval::evalFn(const ValueVector& nodes, EnvironmentPtr env)
 		bindings.push_back(symbol->symbol());
 	}
 
-	// TODO: Remove limitation of 3 arguments
-	// Wrap all other nodes in list and add that as lambda body
+	// If more than one s-exp in lambda body, wrap in list
+	if (nodes.size() > 2) {
+		auto first = std::next(nodes.begin());
+		auto last = std::prev(nodes.end());
+		auto body_nodes = ValueVector(std::distance(first, last) + 2);
+		body_nodes.at(0) = makePtr<Symbol>("do");
+		std::copy(first, nodes.end(), body_nodes.begin() + 1);
+		auto body = makePtr<List>(body_nodes);
+
+		return makePtr<Lambda>(bindings, body, env);
+	}
+
 	return makePtr<Lambda>(bindings, *std::next(nodes.begin()), env);
 }
 
@@ -355,9 +365,9 @@ static bool isSymbol(ValuePtr value, const std::string& symbol)
 		return false;
 	}
 
-	auto valueSymbol = std::static_pointer_cast<Symbol>(value)->symbol();
+	auto value_symbol = std::static_pointer_cast<Symbol>(value)->symbol();
 
-	if (valueSymbol != symbol) {
+	if (value_symbol != symbol) {
 		return false;
 	}
 
diff --git a/src/eval.cpp b/src/eval.cpp
index de014a0..40f99aa 100644
--- a/src/eval.cpp
+++ b/src/eval.cpp
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: MIT
  */
 
-#include <iterator> // sd::advance, std::next, std::prev
+#include <iterator> // std::advance, std::next, std::prev
 #include <list>
 #include <memory> // std::static_pointer_cast
 #include <span>   // std::span