Enums to strings

[Daniel Morissette]

Oopps... I included the wrong version of the lookup function in my 
previous email. It should be:


static char *msGetUnitsStrings(int code)
{
     static char *values[] = MS_UNITS_STRINGS;
     if (code >= 0 && code < _MS_UNITS_COUNT)
         return values[code];
     else
         return "unknown";
}



Daniel Morissette wrote:
> I like the idea of keeping the strings as close as possible to the enum 
> in the .h file to help maintenance. How'bout the following approach that 
> uses a #define to keep the strings close to the enum in the header file?
> 
> In map.h:
> 
> enum MS_UNITS {MS_INCHES, MS_FEET, MS_MILES, MS_METERS, MS_KILOMETERS, 
> MS_DD, MS_PIXELS, _MS_UNITS_COUNT};
> #define MS_UNITS_STRINGS {"inches", "feet", "miles", "meters", 
> "kilometers", "dd", "pixels"}
> 
> 
> Then the lookup function would be implemented as:
> 
> static char **msGetUnitsStrings(int code)
> {
>     static char **values = MS_UNITS_STRINGS;
>     if (code >= 0 && code < _MS_UNITS_COUNT)
>         return values[code];
>     else
>         return "unknown";
> }
> 
> Daniel
> 
> 
> Steve Lime wrote:
> 
>> Option number 2 it is then (with unknown)...
>>
>>
>>>>> Frank Koormann <frank.koormann at INTEVATION.DE> 09/17/05 8:40 AM >>>
>>
>>
>> Dear all,
>>
>> * Frank Warmerdam <warmerdam at POBOX.COM> [050917 05:53]:
>>
>>> On 9/16/05, Steve Lime <steve.lime at dnr.state.mn.us> wrote:
>>>
>>>> I was thinking of just parking the array of strings right next to 
>>>> the enum in map.h, but the function sounds fine too. Were you 
>>>> thinking of something like:
>>>>
>>>> static char **msGetUnitsStrings()
>>>> {
>>>>  static char **values = ...;
>>>>  return values;
>>>> }
>>>>
>>>> or something like:
>>>>
>>>> static char *msGetUnitsString(int code)
>>>> {
>>>>  switch (code) {
>>>>    case 0: return "meters";
>>>>    case 1: return "feet";
>>>>      ...
>>>>   }
>>>>
>>>>   return NULL;
>>>> }
>>>>
>>>> The last element being the count is a good idea. We're doing that 
>>>> with the error codes in maperror.h but no where else I believe.
>>>
>>>
>>> Steve,
>>>
>>> Either way works, but the (very small) advantage of the second is that
>>> it is easier to convert a enum code into a string into the middle of
>>> an expression, such as the arguments to a debug or error message.
>>
>>
>>
>> just a thought since the original need for this function has been 
>> template processing: The second option also would allow to add i18n in 
>> the furture.
>>
>> Regards,
>>
>>         Frank Koormann
> 
>