Pl/pgsql function to count number of same words in two strings

hello forum! could please anyone help me to write a pl/pgsql function to count number of same words in two given strings?
I've given up here:

CREATE OR REPLACE FUNCTION word_match (
1ststr text, 2ndstr text
) RETURNS integer AS $$
BEGIN
a=string_2_array(1ststr, ' ')
b=2ndstr
n=1
FOR n<array_upper(a) LOOP
a[n] ilike '%||b||%'

Than my friend told me that probably it is better to do it through regex like this:
select count(*) from regexp_split_to_table( 'string one', ' ') a where a in (select regexp_split_to_table( 'string two', ' '));

but just for the matter of interest could anyone tell how to do it through pl/pgsql?

thanks a lot! :)))

Your friend's solution seems perfectly valid and simple. Just throw it into a plpgsql function...

yeah thanks! in the end i've just wrote pl/pgsql function based on his suggestion...just wondered probably there is some another way, that doesn't use regex functions....
st_bringer