[Freeciv-Dev] Re: (PR#4594) topology fix for goto route packet

["rwetmore@xxxxxxxxxxxx" <rwetmore@xxxxxxxxxxxx>]

Jason Short wrote:
> rwetmore@xxxxxxxxxxxx wrote:
>>Jason Short wrote:
>>>If the 
>>>client actually does send any real-but-not-normal coordinates then you 
>>>are guaranteed to have a bug (since (-1,-1) is also 
>>>real-but-not-normal), 
>>
>>No, Jason, it is "special", not "real-but-not-normal". Your definition is
>>not the useful one since in fact (-1,-1) is already special and imbedded
>>in the codebase in many places as being special.
> 
> It is real (under certain topologies), 

No, it is always special == unreal. This is the only useful definition,
which *is* the current code definition and should be the topology patch
definition.

> and it is not normal (otherwise 
> everything will break). 

No, the definition of normal is always arbitrary, so this can never be
a hard default or absolute requirement.

> I don't see how this can be up for debate...

Good - stop debating, the current definition is (-1,-1) is special == unreal.
Now just insure the topology patch respects this.

> It is embedded in the current code as being special.  This is fine in 
> the current code, since it is never a real position.  But it leads to 
> problems when it can be a real position because then its definitions as 
> "real-but-not-normal" and "special" conflict.

Only if you create a definition that has such conflicts. So don't keep
trying to do this ... stick with the current definition.

> jason

Note, there is only one topology that requires you to deal with (-1,-1)
as a real coordinate. That is an infinite plane, i.e. one in which all
coordinate values are unique and defined. In this case, removing one or
more of the coordinate locations for special purposes means those
locations are not available within the space. This is the standard
tradeoff against having to define a non-coordinate test. The debate
here currently stands that it is more convenient to define special
values within the coordinate space and lose such locations.

In all other topologies, there is *never* a requirement to use (-1,-1)
as a real coordinate. It is *always* possible to represent the location
as another coordinate value.

Freeciv is unlikely to ever handle the infinite plane case, as there are
too many bounds limitations to be resolved first :-). So there is and will
never be a need in Freeciv to deal with (-1,-1) as a real coordinate. Thus
any further considerations of such a definition or requirement should be
dropped as completely counterproductive.

Cheers,
RossW
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