From c97dbc46af721eaa7648aa63c3f4c537f9d0932f Mon Sep 17 00:00:00 2001
From: Akim Demaille <akim.demaille@gmail.com>
Date: Sun, 13 Dec 2020 08:28:09 +0100
Subject: [PATCH] glr.c: comment changes

* data/skeletons/glr.c (yycompressStack): Reduce scope, and import some
nice comments from glr2.cc.
---
 data/skeletons/glr.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index 8bbb784b..e3550d3a 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -1967,18 +1967,24 @@ yyresolveStack (yyGLRStack* yystackp]b4_user_formals[)
   return yyok;
 }
 
+/** Called when returning to deterministic operation to clean up the extra
+ * stacks. */
 static void
 yycompressStack (yyGLRStack* yystackp)
 {
-  yyGLRState* yyp, *yyq, *yyr;
+  /* yyr is the state after the split point.  */
+  yyGLRState *yyr;
 
   if (yystackp->yytops.yysize != 1 || yystackp->yysplitPoint == YY_NULLPTR)
     return;
 
-  for (yyp = yystackp->yytops.yystates[0], yyq = yyp->yypred, yyr = YY_NULLPTR;
-       yyp != yystackp->yysplitPoint;
-       yyr = yyp, yyp = yyq, yyq = yyp->yypred)
-    yyp->yypred = yyr;
+  {
+    yyGLRState *yyp, *yyq;
+    for (yyp = yystackp->yytops.yystates[0], yyq = yyp->yypred, yyr = YY_NULLPTR;
+         yyp != yystackp->yysplitPoint;
+         yyr = yyp, yyp = yyq, yyq = yyp->yypred)
+      yyp->yypred = yyr;
+  }
 
   yystackp->yyspaceLeft += yystackp->yynextFree - yystackp->yyitems;
   yystackp->yynextFree = YY_REINTERPRET_CAST (yyGLRStackItem*, yystackp->yysplitPoint) + 1;