dollar_strings.txt

CREATE OR REPLACE FUNCTION hello_world(param_your_name text)
RETURNS text AS
$$
SELECT 'Hello world. My name is ' || param_your_name || '.';
$$
language sql STRICT;

SELECT sql_expression($sql$SELECT hello_world($phrase$Regina's elephant's dog$phrase$)
    || $phrase$ I made a cat's meow today.$phrase$ $sql$);