From 482ac3023ea0fcdd66162f1b2c5eb55cd6105403 Mon Sep 17 00:00:00 2001
From: Simon Forman <sforman@hushmail.com>
Date: Sun, 21 Jul 2019 11:50:27 -0700
Subject: [PATCH] Messing with TLA+ in Prolog.

---
 thun/TLA.pl | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 thun/TLA.pl

diff --git a/thun/TLA.pl b/thun/TLA.pl
new file mode 100644
index 0000000..7402259
--- /dev/null
+++ b/thun/TLA.pl
@@ -0,0 +1,102 @@
+
+:- use_module(library(clpfd)).
+
+
+% relly(PC, I, PCnext, Inext).
+
+initial_state :- relly(start, 0, _, _).
+
+relly(start, _I, middle, Inext) :- Inext in 0..1000.
+relly(middle, I,   done, Inext) :- Inext #= I + 1.
+
+
+% next(PC, I) :- 
+next(done, _).
+next(PC, I) :- PC \= done, relly(PC, I, PCnext, Inext), next(PCnext, Inext).
+
+
+% ?- relly(start, 17, middle, 534).
+% true.
+
+% ?- relly(middle, 534, 77, done).
+% false.
+
+% ?- initial_state.
+% true.
+
+% ?- relly(start, 0, PC, I).
+% PC = middle,
+% I in 0..1000.
+
+% ?- relly(start, 0, PC, I), relly(PC, I, PCnext, Inext).
+% PC = middle,
+% PCnext = done,
+% I in 0..1000,
+% I+1#=Inext,
+% Inext in 1..1001.
+
+
+
+type_ok(Small, Big) :- Small in 0..3, Big in 0..5.
+
+initi :- die_hard(0, 0, _, _).
+
+next_dh(Small, Big, S, B) :-
+    B #\= 4,
+    type_ok(Small, Big),
+    die_hard(Small, Big, Si, Bi),
+    write(Small), write(" "), write(Big), write(" -> "), write(Si), write(" "), writeln(Bi),
+    (Bi = 4 -> true ; next_dh(Si, Bi, S, B)).
+next_dh(_, _, _, 4).
+
+
+
+% die_hard(Small, Big, S, B).
+die_hard(Small, Big, 3, Big) :- Small #\= 3, writeln("fill small").  % Fill small.
+die_hard(Small, Big, Small, 5) :- Big #\= 5, writeln("fill big").  % Fill big.
+
+die_hard(Small, Big, 0, Big) :- Small #> 0, writeln("empty small").  % empty small.
+die_hard(Small, Big, Small, 0) :- Big #> 0, writeln("empty big").  % empty big.
+
+die_hard(Small, Big, 0, B) :-  % small to big.
+    Big #< 5, Small #> 0,
+    Small + Big #=< 5,
+    B is Small + Big, writeln("small to big").    
+die_hard(Small, Big, S, 5) :-  % small to big.
+    Big #< 5, Small #> 0,
+    Small + Big #> 5,
+    N is 5 - Big,
+    (N #< Small -> S is Small - N ; S=0), writeln("small to big").    
+
+die_hard(Small, Big, S, 0) :-  % big to small.
+    Small #< 3, Big #> 0,
+    Small + Big #=< 3,
+    S is Small + Big, writeln("big to small").    
+
+die_hard(Small, Big, 3, B) :-  % big to small.
+    Small #< 3, Big #> 0,
+    Small + Big #> 3,
+    N is 3 - Small,
+    (N #< Big -> B is Big - N ; B=0), writeln("big to small").    
+
+/*
+
+call_with_depth_limit(next_dh(0, 0, S, B), 12, REsult).
+
+find...
+
+fill big
+0 0 -> 0 5
+big to small
+0 5 -> 3 2
+empty small
+3 2 -> 0 2
+big to small
+0 2 -> 2 0
+fill big
+2 0 -> 2 5
+big to small
+2 5 -> 3 4
+
+
+*/
\ No newline at end of file
-- 
2.11.0