1 files changed, 52 insertions, 0 deletions
diff --git a/vere/pkg/noun/jets/d/by_urn.c b/vere/pkg/noun/jets/d/by_urn.c
new file mode 100644
index 0000000..5c82876
--- /dev/null
+++ b/vere/pkg/noun/jets/d/by_urn.c
@@ -0,0 +1,52 @@
+/// @file
+
+#include "jets/q.h"
+#include "jets/w.h"
+
+#include "noun.h"
+
+static u3_noun
+_by_urn(u3_noun a, u3j_site* sit_u)
+{
+  if ( u3_nul == a ) {
+    return u3_nul;
+  }
+  else {
+    u3_noun n_a, l_a, r_a, p_n_a;
+    u3x_trel(a, &n_a, &l_a, &r_a);
+    p_n_a = u3h(n_a);
+
+    u3k(p_n_a);
+    u3k(n_a);
+    u3k(l_a);
+    u3k(r_a);
+
+    u3_noun pro = u3nt(u3nc(p_n_a, u3j_gate_slam(sit_u, n_a)),
+      _by_urn(l_a, sit_u),
+      _by_urn(r_a, sit_u));
+    
+    u3z(a);
+    return pro;
+  }
+}
+
+u3_noun
+u3qdb_urn(u3_noun a, u3_noun b)
+{
+  u3_noun    pro;
+  u3j_site sit_u;
+
+  u3j_gate_prep(&sit_u, u3k(b));
+  pro = _by_urn(u3k(a), &sit_u);
+  u3j_gate_lose(&sit_u);
+
+  return pro;
+}
+
+u3_noun
+u3wdb_urn(u3_noun cor)
+{
+  u3_noun a, b;
+  u3x_mean(cor, u3x_sam, &b, u3x_con_sam, &a, 0);
+  return u3qdb_urn(a, b);
+}