From: Stephen North <north@pome.client.research.att.com>
Date: Thu, 22 Aug 2013 18:33:12 +0000 (-0400)
Subject: Another try at fixing the bug involving the parser and edges involving subgraphs.
X-Git-Tag: LAST_LIBGRAPH~32^2~62
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=eb2ac0456819ada78e83b5bdbb719ab4cba8704d;p=graphviz

Another try at fixing the bug involving the parser and edges involving subgraphs.
For example consider
digraph G { a -> b -> {c d} }
digraph G { {rank=same; X Y}  a -> X -> Y}
digraph G { a -> b -> {rank=same; X -> Y [color=red]} [color=blue]; }
In the last example the parser has to keep the anonymous subgraph around
as part of the edgelist being constructed, but when [color=blue] is parsed
it is no longer the "current subgraph".  There are Details. One idea is
that if this continues to be a source of errors, we could overhaul the
parser a bit more aggressively to make better use of the parser's own
stack and employ appropriate types for nodelist, subgraph, edgelist, attrlist
etc. rather than rely on the explicit stack gstack_t *S. Something to consider.
---

diff --git a/lib/cgraph/grammar.y b/lib/cgraph/grammar.y
index d8cb343c6..b7d95dfc3 100644
--- a/lib/cgraph/grammar.y
+++ b/lib/cgraph/grammar.y
@@ -126,7 +126,7 @@ compound 	:	simple rcompound optattr
 
 simple		:	nodelist | subgraph ;
 
-rcompound	:	T_edgeop {getedgeitems(1);} simple rcompound {getedgeitems(2); $$ = 1;}
+rcompound	:	T_edgeop {getedgeitems(1);} simple {getedgeitems(2);} rcompound {$$ = 1;}
 			|	/* empty */ {$$ = 0;}
 			;
 
@@ -376,6 +376,10 @@ static void appendnode(char *name, char *port, char *sport)
 }
 
 /* apply current optional attrs to nodelist and clean up lists */
+/* what's bad is that this could also be endsubg.  also, you can't
+clean up S->subg in closesubg() because S->subg might be needed
+to construct edges.  these are the sort of notes you write to yourself
+in the future. */
 static void endnode()
 {
 	item	*ptr;
@@ -385,6 +389,8 @@ static void endnode()
 		applyattrs(ptr->u.n);
 	deletelist(&(S->nodelist));
 	deletelist(&(S->attrlist));
+	deletelist(&(S->edgelist));
+	S->subg = 0;  /* notice a pattern here? :-( */
 }
 
 /* edges - store up node/subg lists until optional edge key can be seen */