From aa0e3e3c9fd6bf174493e4ab1e3c292fc924a4f0 Mon Sep 17 00:00:00 2001
From: ThorstenB <brehmt@gmail.com>
Date: Sat, 29 Oct 2011 21:20:46 +0200
Subject: [PATCH] #453: Using = as Nasal function argument crashes FG Keep
 Nasal parser from crashing when "=" function misses a left-hand element, i.e.
 when parsing "sin(=)". (Or do people writing such terrible syntax deserve a
 crash? ;-) ).

---
 simgear/nasal/codegen.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/simgear/nasal/codegen.c b/simgear/nasal/codegen.c
index d1c05ef6..059c1144 100644
--- a/simgear/nasal/codegen.c
+++ b/simgear/nasal/codegen.c
@@ -536,6 +536,9 @@ static void genAssign(struct Parser* p, struct Token* t)
 {
     struct Token *lv = LEFT(t), *rv = RIGHT(t);
     int len, dummy, var=0;
+    if (!lv)
+        naParseError(p, "bad assignment, missing variable", t->line);
+    else
     if(parListLen(lv) || (lv->type == TOK_VAR && parListLen(RIGHT(lv)))) {
         if(lv->type == TOK_VAR) { lv = RIGHT(lv); var = 1; }
         len = parListLen(lv);