The function takes some expression as the argument and executes it, returning output in the varchar string
CREATE OR REPLACE FUNCTION eval (expr VARCHAR2) RETURN VARCHAR2
AS
ret VARCHAR2(4000);
BEGIN
EXECUTE IMMEDIATE 'begin :result := ' || expr || '; end;' USING OUT ret;
RETURN ret;
END;
/
AS
ret VARCHAR2(4000);
BEGIN
EXECUTE IMMEDIATE 'begin :result := ' || expr || '; end;' USING OUT ret;
RETURN ret;
END;
/
The discussion and examples could be found there
