From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Wed, 17 Feb 2016 19:55:36 +0000 (+0100)
Subject: Allow promotion choice in engine-defined variants
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=a2f3d790becbea6cd93ec51add89f2251a90bba4;p=xboard.git

Allow promotion choice in engine-defined variants

When variant shatranj, courier or makruk, which normally do not have
promotion choice, are used as parent for an engine-defined variant,
we now invoke the piece-selection routine. This to make these variants
also suitable as parent for variants that do have choice (e.g. to give
them the baring rule, which is unique for Shatranj).
---

diff --git a/backend.c b/backend.c
index bc6ec28..b49ba15 100644
--- a/backend.c
+++ b/backend.c
@@ -6742,7 +6742,7 @@ HasPromotionChoice (int fromX, int fromY, int toX, int toY, char *promoChoice, i
 	    *promoChoice = PieceToChar(p++);
 	    if(*promoChoice != '.') break;
 	}
-	return FALSE;
+	if(!*engineVariant) return FALSE; // if used as parent variant there might be promotion choice
     }
     // no sense asking what we must promote to if it is going to explode...
     if(gameInfo.variant == VariantAtomic && boards[currentMove][toY][toX] != EmptySquare) {
@@ -7449,8 +7449,8 @@ CanPromote (ChessSquare piece, int y)
 	// some variants have fixed promotion piece, no promotion at all, or another selection mechanism
 	if(IS_SHOGI(gameInfo.variant)          || gameInfo.variant == VariantXiangqi ||
 	   gameInfo.variant == VariantSuper    || gameInfo.variant == VariantGreat   ||
-	   gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
-         gameInfo.variant == VariantMakruk) return FALSE;
+	  (gameInfo.variant == VariantShatranj || gameInfo.variant == VariantCourier ||
+           gameInfo.variant == VariantMakruk) && !*engineVariant) return FALSE;
 	return (piece == BlackPawn && y <= zone ||
 		piece == WhitePawn && y >= BOARD_HEIGHT-1-zone ||
 		piece == BlackLance && y <= zone ||