Enhance pgn_to_plain.py

in case a score can be parsed from the comment field in the pgn, add it to the output.
This form works for the fishtest pgns, and is quite common (cutechess-cli among others).

script/pgn_to_plain.py

@@ -1,11 +1,15 @@
 import chess.pgn
 import argparse
 import glob
+import re
 from typing import List
 
 # todo close in c++ tools using pgn-extract
 # https://www.cs.kent.ac.uk/people/staff/djb/pgn-extract/help.html#-w
 
+commentRe = re.compile("([+-]*M*[0-9.]*)/([0-9]*)")
+mateRe = re.compile("([+-])M([0-9]*)")
+
 def parse_result(result_str:str, board:chess.Board) -> int:
     if result_str == "1/2-1/2":
         return 0
@@ -20,7 +24,7 @@ def parse_result(result_str:str, board:chess.Board) -> int:
         else:
             return -1
     else:
-        print("illeagal result", result_str)
+        print("illegal result", result_str)
         raise ValueError
 
 def game_sanity_check(game: chess.pgn.Game) -> bool:
@@ -29,20 +33,51 @@ def game_sanity_check(game: chess.pgn.Game) -> bool:
         return False
     return True
 
+def parse_comment_for_score(comment_str: str, board: chess.Board) -> int:
+    global commentRe
+    global mateRe
+
+    try:
+      m = commentRe.search(comment_str)
+      if m:
+         score = m.group(1)
+         # depth = int(m.group(2))
+         m = mateRe.search(score)
+         if m:
+            if m.group(1) == "+":
+               score =  32000 - int(m.group(2))
+            else:
+               score = -32000 + int(m.group(2))
+         else:
+            score = int(float(score) * 208) # pawn to SF PawnValueEg
+
+         if board.turn == chess.BLACK:
+            score = -score
+      else:
+         score = 0
+    except:
+      score = 0
+
+    return score
+    
 def parse_game(game: chess.pgn.Game, writer, start_play: int=1)->None:
     board: chess.Board = game.board()
     if not game_sanity_check(game):
         return
+
     result: str = game.headers["Result"]
-    for ply, move in enumerate(game.mainline_moves()):
+    ply = 0
+    for node in game.mainline():
+        move = node.move
         if ply >= start_play:
+            comment: str = node.comment
             writer.write("fen " + board.fen() + "\n")
             writer.write("move " + str(move) + "\n")
-            writer.write("score 0\n")
+            writer.write("score " + str(parse_comment_for_score(comment, board)) + "\n")
             writer.write("ply " + str(ply)+"\n")
             writer.write("result " + str(parse_result(result, board)) +"\n")
             writer.write("e\n")
-
+        ply += 1
         board.push(move)
 
 def main():
@@ -53,6 +88,7 @@ def main():
     args = parser.parse_args()
 
     pgn_files: List[str] = glob.glob(args.pgn)
+    pgn_files = sorted(pgn_files, key=lambda x:float(re.findall("-(\d+).pgn",x)[0] if re.findall("-(\d+).pgn",x) else 0.0))
     f = open(args.output, 'w')
     for pgn_file in pgn_files:
         print("parse", pgn_file)