Re: Add Roman numeral conversion to to_number

On Sun, Sep 17, 2017 at 6:43 PM, David Fetter <david(at)fetter(dot)org> wrote:

> On Sat, Sep 16, 2017 at 10:42:49PM +0000, Douglas Doole wrote:
> > Oliver, I took a look at your tests and they look thorough to me.
> >
> > One recommendation, instead of having 3999 separate selects to test every
> > legal roman numeral, why not just do something like this:
> >
> > do $$
> > declare
> > i int;
> > rn text;
> > rn_val int;
> > begin
> > for i in 1..3999 loop
> > rn := trim(to_char(i, 'rn'));
> > rn_val := to_number(rn, 'rn');
> > if (i <> rn_val) then
> > raise notice 'Mismatch: i=% rn=% rn_val=%', i, rn, rn_val;
> > end if;
> > end loop;
> > raise notice 'Tested roman numerals 1..3999';
> > end;
> > $$;
> >
> > It's a lot easier to maintain than separate selects.
>
> Why not just one SELECT, as in:
>
> SELECT i, to_char(i, 'rn'), to_number(to_char(i, 'rn'), 'rn');
> FROM generate_series(1,3999) i
>

Question: What is our definition of a legal Roman numeral?

For example sometimes IXX appears in the corpus to refer to 19 even though
our standardised notation would be XIX.

>
> Best,
> David.
> --
> David Fetter <david(at)fetter(dot)org> http://fetter.org/
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