select n.nspname as function_schema,
p.proname as function_name,
l.lanname as function_language,
case when l.lanname = 'internal' then p.prosrc
else pg_get_functiondef(p.oid)
end as definition,
pg_get_function_arguments(p.oid) as function_arguments,
t.typname as return_type
from pg_proc p
left join pg_namespace n on p.pronamespace = n.oid
left join pg_language l on p.prolang = l.oid
left join pg_type t on t.oid = p.prorettype
where n.nspname not in ('pg_catalog', 'information_schema')
order by function_schema,
function_name;