Can you make "illegal" (not dead) rows orange please?

miguel-ambrona / deadpos

A tool for analyzing chess compositions based on dead reckoning

GNU General Public License v3.0

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Can you make "illegal" (not dead) rows orange please? #33

Closed andrew-buchanan closed 10 months ago

andrew-buchanan commented 10 months ago

There are 4 kinds of row that appear after r command: red "illegal dead" red "illegal" (alive) yellow (legal) "dead" green "" (legal, alive)

Yes?

The second row, could that be orange please?

miguel-ambrona commented 10 months ago

Hi Andrew. Version 2.3 (still WIP) now introduced the notion of "zombie", so I believe the above is obsolete.

We now have three classes of positions:

illegal: same as FIDE (no game following the rules can reach the position).
zombie: legal, but all possible restractions are dead.
legal and not zombie (a reachable position following the mobility rules + DP).

Note that the "dead" keyword is an orthogonal notion (it indicates that the position is dead when this is relevant, because it is either the result of a retraction or the middle of a longer forward sequence).

andrew-buchanan commented 10 months ago

Hi thanks for this.

So, there are 5 different statuses possible. Currently each of them is identified separately, but the colours of (1)&(2) are the same.

(1) FIDE illegal + dead (red) (2) FIDE illegal + alive (red) (3) FIDE legal + zombie (blue) (4) FIDE legal + non-zombie dead (yellow) (5) FIDE legal + alive (green)

As long as (1) & (2) are separate, which they are, I would still like (2) to be orange, please, because it's kind of a retro try. Hopefully this will be very easy.

Note "dead" is not quite orthogonal to your 3 bullets, because zombie can only be dead, not living.

miguel-ambrona commented 10 months ago

I'll use magenta as orange is not available.

I still support the idea that the term "dead" is independent.

When analyzing legality, the current position is not analyzed for dead/alive. The fact that zombie implies dead is a nice subtlety derived from the fact that from dead one cannot reach alive.

Consider the following example.

>>> K7/2k5/8/8/8/8/8/8 ? >>= legal
K7/2k5/8/8/8/8/8/8 w - - ? 1                                                    
zombie K7/2k5/8/8/8/8/8/8 b - - ? 1                                             
nsols 1

Here the liveness of the given position (either WTM or BTM) has never been explicitly analyzed (because it does not come from a retraction in the stipulation). Still, it has been labeled as zombie, because it is FIDE legal, but all its FIDE legal retractions are dead.