[fpc-pascal] Re: StrUtils.RomanToInt oddities

[Bart]

On 9/23/13, Lukasz Sokol <el.es.cr at gmail.com> wrote:

> function TryRomanToInt(AInput:String; out AResult: integer):boolean;
> var i, Len, N, Np1 : integer;
[snip]
>
>
>         if N >= Np1 then AResult := AResult + N
>         else AResult := AResult - N;
>
>       end;
>     else // i = Len-1 = last char we just add (consider : MCM : add 1000,

Compiler doesn't like the else here. I removed the ; after the end 1 line above.

> sub 100, add 1000 = 1900)
>      begin
>        AResult := AResult + N;
>      end;
>   end; // for
>   // if the above, after all characters are through, has resulted in 0 or
> less,
>   // we invalidate everything at the end (consider : CMLM, IIIM )
>
>   Result := AResult > 0;
>   if not Result then AResult := 0;
> end;
>
> (only mind-compiled ;) tests welcome ;) )
>

It produces "odd" output though:

C:\Users\Bart\LazarusProjecten\ConsoleProjecten>test
Enter Roman numeral: LL  //should be illegal
TryRomanToInt('LL') -> 50
StrUtils.RomanToInt('LL') = 100

Enter Roman numeral: MM
TryRomanToInt('MM') -> 1050  //obviously should be 2000
StrUtils.RomanToInt('MM') = 2000

Enter Roman numeral: II
TryRomanToInt('II') -> 1051  // nice one!
StrUtils.RomanToInt('II') = 2

So, it's a little bit flawed.

Anyhow, let's not focus upon what the new code should be.
The question was: is current behaviour (accepting IIMIIC etc.) a bug or not.

Bart