hstore_pllua

pig repo add pgsql -u   # add both repo and update cache

pig install pllua;		# install via package name, for the active PG version
pig install hstore_pllua;		# install by extension name, for the current active PG version

pig install hstore_pllua -v 18;   # install for PG 18
pig install hstore_pllua -v 17;   # install for PG 17
pig install hstore_pllua -v 16;   # install for PG 16
pig install hstore_pllua -v 15;   # install for PG 15
pig install hstore_pllua -v 14;   # install for PG 14

CREATE EXTENSION hstore_pllua CASCADE; -- requires hstore, pllua

CREATE EXTENSION hstore;
CREATE EXTENSION pllua;
CREATE EXTENSION hstore_pllua;

CREATE FUNCTION process_hstore(h hstore) RETURNS hstore LANGUAGE pllua AS $$
  -- h is a Lua table with string keys and string values
  h["new_key"] = "new_value"
  h["modified"] = "true"
  return h
$$;

SELECT process_hstore('name => "Alice", age => "30"'::hstore);

CREATE FUNCTION hstore_keys(h hstore) RETURNS SETOF text LANGUAGE pllua AS $$
  for k, v in pairs(h) do
    coroutine.yield(k)
  end
$$;