transliteration in plpgsql

transliterate.sql

CREATE OR REPLACE FUNCTION transliterate(my_text VARCHAR) RETURNS varchar AS $$
DECLARE 
text_out VARCHAR DEFAULT '';
BEGIN
text_out := my_text;
text_out := translate(text_out, 'áàâäåáăąãāçċćčĉéèėëêēĕîïìíīñôöøõōùúüûūýÿỳ', 'aaaaaaaaaaccccceeeeeeeiiiiinooooouuuuuyyy');
text_out := translate(text_out, 'ÁÀÂÄÅÁĂĄÃĀÇĊĆČĈÉÈĖËÊĒĔÎÏÌÍĪÑÔÖØÕŌÙÚÜÛŪÝŸỲ', 'AAAAAAAAAACCCCCEEEEEEEIIIIINOOOOOUUUUUYYY');
text_out := replace(text_out, 'æ', 'ae');
text_out := replace(text_out, 'Œ', 'OE');
text_out := replace(text_out, 'Æ', 'AE');
text_out := replace(text_out, 'ß', 'ss');
text_out := replace(text_out, 'œ', 'oe');

RETURN text_out;
END;
$$ LANGUAGE plpgsql IMMUTABLE;