Generate series for various mixes of numbers and letteres - postgresql

Question

I am using this syntax:
generate_series(1, COALESCE((string_to_array(table.id_number, '-')) [2] :: INT, 1)) AS n (numbers)
To generate IDs in elements that have got ID like 32.22.1-4 to get 4 rows with IDs 32.22.1, 32.22.2, 32.22.3 and 32.22.4. How to change it to accept also letters?
So for 32.22.a-c there would be:
32.22.a, 32.22.b, 32.22.c
And for 32.22.d1-d4 there would be
32.22.d1, 32.22.d2, 32.22.d3, 32.22.d4
EDIT:
The whole code looks like:
INSERT INTO ...
(
SELECT
...
FROM table
CROSS JOIN LATERAL
generate_series(1, COALESCE((string_to_array(table.id_number, '-')) [2] :: INT, 1)) AS n (numbers)
WHERE table.id_number LIKE ...
);

Answer 1

WITH t(id_number) AS ( VALUES
('32.33.a1-a5'::TEXT),
('32.34.a-c'::TEXT),
('32.35.b-e'::TEXT)
), stats AS (
SELECT
chars,
chars[1] pattern, -- pattern use
CASE
WHEN (ascii(chars[3]) - ascii(chars[2])) = 0
THEN FALSE
ELSE TRUE
END char_pattern, -- check if series of chars
CASE
WHEN (ascii(chars[3]) - ascii(chars [2])) = 0
THEN right(chars[3],1)::INTEGER
ELSE (ascii(chars[3]) + 1 - ascii(chars[2]))::INTEGER
END i -- number of series
FROM t,
regexp_matches(t.id_number, '(.*\.)(\w*)-(\w*)$') chars
)
SELECT
CASE WHEN char_pattern
THEN pattern || chr(ascii(chars[2]) - 1 + s)
ELSE pattern || left(chars[2],1) || s::TEXT
END output
FROM stats,generate_series(1,stats.i) s;
Result:
output
---------
32.33.a1
32.33.a2
32.33.a3
32.33.a4
32.33.a5
32.34.a
32.34.b
32.34.c
32.35.b
32.35.c
32.35.d
32.35.e
(12 rows)