[Freeciv-Dev] Re: [PATCH] Map cleanups (PR#1208)

[Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxx>]

On Tue, Jan 08, 2002 at 12:26:00AM -0500, Ross W. Wetmore wrote:
> 
> I actually like something like this better than nearest_real_pos(). I am
> assuming when it is expressed correctly it effectively returns the original
> unstepped coordinates. More importantly, it should clearly document that 
> this is what it does as part of the interface.
> 
> The case where one steps in a loop until move points are exhausted, and
> hits an unreal tile along the way (causing a serious slowdown in game
> response :-) is at least indirectly covered by this warning/documentation
> then.
> 
> At 05:23 AM 02/01/07 -0500, Jason Short wrote:
> >jdorje@xxxxxxxxxxxxxxxxxxxxx wrote:
> >
> >
> >> I do think SAFE_MAPSTEP is wrongly implemented.  It needn't use 
> >> nearest_real_pos but should instead do
> >>   #define SAFE_MAPSTEP(x, y)
> >>   {
> >>     int _x = x, _y = y;
> >>     if (!normalize_map_pos(&x, &y)) {
> >>       x = _x;
> >>       y = _y;
> >>     }
> >>   }
> >
> >Oops - I forgot I snuck this in in the most recent tilespec fix.  So 
> >scratch that idea :-).
> >
> >jason
> 
> But if you look closely ...
> 
> In fact what you have done here is one of the many local variants of
> normalize_map_pos() that are going to spring up because you didn't 
> make the condition we all say is desired, i.e. the one used here, part
> of the interface, and thus force people to implement this privately all 
> over the codebase.
> 
> It is better to just do it. Think of it as a code reduction measure, 
> i.e. of all the duplicate code you are saving by moving it into the
> implementation from just outside :-).
> 
> If someone really wants arbitrary values returned, and the void_tile
> sentiments revive to carry the day to give this a new lease on life, 
> then it is possible to expose the underlying internal interface in 
> normalize_map_pos(), i.e. below the is_real check and let them 
> experience the Chinese curse of "may you live in interesting times".
> 
> This way at least code that uses the primary interface won't suffer.
> And you will have to go slightly out of your way to do the stupid
> thing. It is always wise to make the defaults safe, and not the 
> "special" case :-).

Ross I completely agree with you. 

*trumpets* A historical date. *trumpets*

        Raimar

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