no.py

def node_lookup(nodes):
  tpl = "pub(crate) unsafe fn {}node_lookup<K: Key>(ptr: {}, key: &K) -> Result<Lookup, LookupError> {{"
  "\n\n".join(["".join(tidy(group(
    inline(opener),
    "let raw = ptr.as_ptr_unchecked() as *mut u8;",
    "prefetch_node(raw);",
    "let tag = ptr.tag();",
    debug("if tag != 0 { debug_assert!((&*raw.cast::<NodeHeader>()).tag == tag); }"),
    group(
      "match tag {",
      "node_tag::NULL     => Err(LookupError::Null),",
      "node_tag::ELEMENT  => Ok(Lookup::Element(ptr)),",
      "node_tag::COMPOUND => Ok(Lookup::Compound(ptr)),",
      *just_cols(
        ["node_tag::{}".format(node.tag_const()) for node in nodes],
        ["=> Ok(Lookup::Index((&*(raw as *const {})).lookup(key))),".format(node.mono()) for node in nodes],
      ),
      "_ => Err(LookupError::CorruptNodeTag(tag)),"
    )))) for opener in [
    not_storage(tpl.format("",      "NodePtr")),
    storage(    tpl.format("",      "MemPtr")),
    storage(    tpl.format("disk_", "LoadedPtr")),
  ]])