From: NeilBrown <neil@brown.name>
Date: Fri, 5 Mar 2021 10:17:51 +0000 (+1100)
Subject: parergen: fix bug in deriving itemsets
X-Git-Url: https://ocean-lang.org/code/?p=ocean;a=commitdiff_plain;h=61c1380f14481ee8883f9e38d711b7ea8fe3661e

parergen: fix bug in deriving itemsets

The code to check if an item had already been added, was wrong.

Signed-off-by: NeilBrown <neil@brown.name>
---

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index fc95688..a6486df 100644
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -1488,18 +1488,21 @@ itemsets (or merged with a pre-existing itemset).
 				continue;
 			if (pr->body[bp] != sym)
 				continue;
+
+			bp += 1;
 			if (type >= LALR)
 				la = is->items.data[j];
-			pos = symset_find(&newitemset, pr->head->num);
-			if (bp + 1 == pr->body_size &&
+			if (bp == pr->body_size &&
 			    pr->precedence > 0 &&
 			    pr->precedence > precedence) {
 				// new itemset is reducible and has a precedence.
 				precedence = pr->precedence;
 				assoc = pr->assoc;
 			}
+			pos = symset_find(&newitemset, item_num(p, bp));
+
 			if (pos < 0)
-				symset_add(&newitemset, item_num(p, bp+1), la);
+				symset_add(&newitemset, item_num(p, bp), la);
 			else if (type >= LALR) {
 				// Need to merge la set.
 				int la2 = newitemset.data[pos];