Rework how attributes and properties are accessed.

Made the fact that properties belong to an attribute shine through to
scheme. This by setting the SCM field in the strbuf:ers in my
vcomponents to a pair of their old SCM value, and a hash table
representing the properties.

This also meant that the primitive set-attribute! could be replaced by a
set-car! on the pair returned by the primitive get-attribute. And that
both set- and get-property now simple works on the hash table returned
by get-attribute.

The major problem with this release was that I for a while missed that
DEEP_COPY(strbuf) now also needed to deep copy the SCM values. Without
that attributes in a copied vcomponent would be shared with the
original. This mainly lead to repeating events all being the same.

1 files changed, 7 insertions, 2 deletions

diff --git a/src/strbuf.c b/src/strbuf.c
index c7e3f2b5..66fe2989 100644
--- a/src/strbuf.c
+++ b/src/strbuf.c
@@ -70,8 +70,13 @@ int DEEP_COPY(strbuf)(strbuf* dest, strbuf* src) {
 	}
 
 	if (src->scm != NULL) {
-		/* The magic SCM type is copied when reassigned. */
-		dest->scm = src->scm;
+		/*
+		 * Upon Vcomponent binding into scheme I place all
+		 * strings inside cons cells. This leads to a deep
+		 * copy being required. copy-tree however returns
+		 * the same object for atoms and scheme strings.
+		 */
+		dest->scm = scm_copy_tree(src->scm);
 		/* NOTE This is a bit of a leaky abstraction.  */
 		scm_gc_protect_object(dest->scm);
 	}