fix bug in primitiveJoin()

1 files changed, 13 insertions, 10 deletions

diff --git a/liblali.c b/liblali.c
index efbcd3f..7394ca3 100644
--- a/liblali.c
+++ b/liblali.c
@@ -1040,27 +1040,30 @@ Object *primitiveJoin(Object **args, GC_PARAM) {
   else if ((*args)->car->type != TYPE_CONS)
     exceptionWithObject((*args)->car, "is not a list");
 
-  unsigned long i = 1;
   Object *tmpCons = (*args)->car;
+  unsigned long i = strlen(tmpCons->car->string);
   for (; tmpCons->cdr != nil; tmpCons = tmpCons->cdr)
-    i += strlen(tmpCons->car->string);
+    i += strlen(tmpCons->cdr->car->string);
 
-  char symbolResult[i];
+  char symbolResult[i+1];
   tmpCons = (*args)->car;
   unsigned long wordLength = strlen(tmpCons->car->string);
+  unsigned long j = 0;
 
   // first list element
-  for (int j = 0; j < wordLength; j++)
+  for (; j < wordLength; j++)
       symbolResult[j] = tmpCons->car->string[j];
 
   // rest of list elements
-  for (i = wordLength; tmpCons->cdr != nil; tmpCons = tmpCons->cdr) {
-    wordLength = strlen(tmpCons->cdr->car->string);
-    for (int j = 0; j < wordLength; j++)
-      symbolResult[i+j] = tmpCons->cdr->car->string[j];
-    i += wordLength;
+  if (tmpCons->cdr->car != nil) {
+    for (i = wordLength; tmpCons->cdr != nil; tmpCons = tmpCons->cdr) {
+      wordLength = strlen(tmpCons->cdr->car->string);
+      for (j = 0; j < wordLength; j++)
+        symbolResult[i+j] = tmpCons->cdr->car->string[j];
+      i += j;
+    }
   }
-
+  symbolResult[i] = '\0';
   return newSymbol(symbolResult, GC_ROOTS);
 }