Smart substring in plpgsql

cut_nicely.sql

CREATE OR REPLACE FUNCTION cut_nicely(my_string VARCHAR, my_length INTEGER) RETURNS varchar AS $$
DECLARE
  my_pointer INTEGER;
BEGIN
  my_pointer := my_length;
  WHILE my_pointer < length(my_string) AND transliterate(substr(my_string, my_pointer, 1)) ~* '[a-z]' LOOP
    my_pointer := my_pointer + 1;
  END LOOP;

  RETURN substr(my_string, 1, my_pointer);
END;
$$ LANGUAGE plpgsql
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