From 567c3d8dc28e99278b5db0edf53e93783e835fe9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Janouch?= <p.janouch@gmail.com>
Date: Sun, 21 May 2017 08:27:47 +0200
Subject: [PATCH] Fix missing argument values

---
 ell.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/ell.c b/ell.c
index d925523..6becbe9 100755
--- a/ell.c
+++ b/ell.c
@@ -756,11 +756,12 @@ execute_args (struct context *ctx, struct item *args, struct item **res) {
 		struct item *evaluated = NULL;
 		if (!execute_statement (ctx, args, &evaluated))
 			return false;
-		if (evaluated) {
-			item_free_list (evaluated->next);
-			evaluated->next = NULL;
-			res = &(*res = evaluated)->next;
-		}
+		// Arguments should not evaporate, default to a nil value
+		if (!evaluated && !check (ctx, (evaluated = new_list (NULL))))
+			return false;
+		item_free_list (evaluated->next);
+		evaluated->next = NULL;
+		res = &(*res = evaluated)->next;
 	}
 	return true;
 }
@@ -806,8 +807,8 @@ execute_statement
 	if (statement->type == ITEM_STRING)
 		return check (ctx, (*result = new_clone (statement)));
 
-	// XXX: should this ever happen and what are the consequences?
-	//   Shouldn't we rather clone the empty list?
+	// Executing a nil value results in no value.  It's not very different from
+	// calling a block that returns no value--it's for our callers to resolve.
 	struct item *body;
 	if (!(body = statement->head))
 		return true;