1 files changed, 78 insertions, 0 deletions
diff --git a/vere/pkg/noun/jets/d/by_apt.c b/vere/pkg/noun/jets/d/by_apt.c
new file mode 100644
index 0000000..66a6414
--- /dev/null
+++ b/vere/pkg/noun/jets/d/by_apt.c
@@ -0,0 +1,78 @@
+/// @file
+
+#include "jets/q.h"
+#include "jets/w.h"
+
+#include "noun.h"
+
+static c3_o
+_by_apt(u3_noun a, u3_weak l, u3_weak r)
+{
+  if ( u3_nul == a ) {
+    return c3y;
+  }
+  else {
+    u3_noun p_n_a, l_a, r_a;
+    {
+      u3_noun n_a;
+      u3x_trel(a, &n_a, &l_a, &r_a);
+      p_n_a = u3h(n_a);
+    }
+
+    if ( u3_none != l ) {
+      if (  (c3n == u3qc_gor(p_n_a, l))
+         || (c3y == u3r_sing(p_n_a, l)) )
+      {
+        return c3n;
+      }
+    }
+
+    if ( u3_none != r ) {
+      if (  (c3n == u3qc_gor(r, p_n_a))
+         || (c3y == u3r_sing(r, p_n_a)) )
+      {
+        return c3n;
+      }
+    }
+
+    if ( u3_nul != l_a ) {
+      u3_noun p_n_l_a = u3h(u3h(l_a));
+
+      if (  (c3n == u3qc_mor(p_n_a, p_n_l_a))
+         || (c3y == u3r_sing(p_n_a, p_n_l_a)) )
+      {
+        return c3n;
+      }
+
+      if ( c3n == _by_apt(l_a, p_n_a, r) ) {
+        return c3n;
+      }
+    }
+
+    if ( u3_nul != r_a ) {
+      u3_noun p_n_r_a = u3h(u3h(r_a));
+
+      if (  (c3n == u3qc_mor(p_n_a, p_n_r_a))
+         || (c3y == u3r_sing(p_n_a, p_n_r_a)) )
+      {
+        return c3n;
+      }
+
+      return _by_apt(r_a, l, p_n_a);
+    }
+
+    return c3y;
+  }
+}
+
+u3_noun
+u3qdb_apt(u3_noun a)
+{
+  return _by_apt(a, u3_none, u3_none);
+}
+
+u3_noun
+u3wdb_apt(u3_noun cor)
+{
+  return u3qdb_apt(u3x_at(u3x_con_sam, cor));
+}