From 1f84be6944ee48b72a33cf064661fa1a2129b885 Mon Sep 17 00:00:00 2001
From: H.G. Muller <h.g.muller@hccnet.nl>
Date: Fri, 22 Oct 2010 20:30:06 +0200
Subject: [PATCH] Make starting new variation dependent on shift key

The shift key is read during mouse events, and posted in a global
variable, which can then be used by the back-end. The decision to start
a new variation (pushing the game tail rather than clipping it off) when
entring a move in Edit Game or Analyze mode is made dependent on this.
The move-typein also records the shift-key state.
---
 backend.c           |    3 ++-
 frontend.h          |    1 +
 winboard/winboard.c |    5 ++++-
 xboard.c            |    6 ++++--
 4 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/backend.c b/backend.c
index 8a63a43..ea13ca8 100644
--- a/backend.c
+++ b/backend.c
@@ -449,6 +449,7 @@ int adjudicateLossPlies = 6;
 char white_holding[64], black_holding[64];
 TimeMark lastNodeCountTime;
 long lastNodeCount=0;
+int shiftKey; // [HGM] set by mouse handler
 
 int have_sent_ICS_logon = 0;
 int sending_ICS_login    = 0;
@@ -6160,7 +6161,7 @@ FinishMove(moveType, fromX, fromY, toX, toY, promoChar)
      the previous line in Analysis Mode */
   if ((gameMode == AnalyzeMode || gameMode == EditGame)
 				&& currentMove < forwardMostMove) {
-    if(appData.variations) PushTail(currentMove, forwardMostMove); // [HGM] vari: save tail of game
+    if(appData.variations && shiftKey) PushTail(currentMove, forwardMostMove); // [HGM] vari: save tail of game
     else forwardMostMove = currentMove;
   }
 
diff --git a/frontend.h b/frontend.h
index 15a955c..14fa176 100644
--- a/frontend.h
+++ b/frontend.h
@@ -160,6 +160,7 @@ void CmailSigHandlerCallBack P((InputSourceRef isr, VOIDSTAR closure,
 				char *buf, int count, int error));
 
 extern ProcRef cmailPR;
+extern int shiftKey;
 
 /* in xgamelist.c or winboard.c */
 void GLT_ClearList();
diff --git a/winboard/winboard.c b/winboard/winboard.c
index 50102ca..afef6ae 100644
--- a/winboard/winboard.c
+++ b/winboard/winboard.c
@@ -4073,6 +4073,8 @@ MouseEvent(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
     x = BOARD_WIDTH - 1 - x;
   }
 
+  shiftKey = GetKeyState(VK_SHIFT) < 0; // [HGM] remember last shift status
+
   switch (message) {
   case WM_LBUTTONDOWN:
       if (PtInRect((LPRECT) &whiteRect, pt)) {
@@ -6365,7 +6367,8 @@ TypeInMoveDialog(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
 
   case WM_COMMAND:
     switch (LOWORD(wParam)) {
-    case IDOK:
+    case IDOK:
+      shiftKey = GetKeyState(VK_SHIFT) < 0; // [HGM] remember last shift status
       GetDlgItemText(hDlg, OPT_Move, move, sizeof(move));
       { int n; Board board;
 	// [HGM] FENedit
diff --git a/xboard.c b/xboard.c
index d9f382a..80e622e 100644
--- a/xboard.c
+++ b/xboard.c
@@ -1079,8 +1079,9 @@ char globalTranslations[] =
                                 \"Send to second chess program:\",,2) \n";
 
 char boardTranslations[] =
-   "<Btn1Down>: HandleUserMove() \n \
-   <Btn1Up>: HandleUserMove() \n \
+   "<Btn1Down>: HandleUserMove(0) \n \
+   Shift<Btn1Up>: HandleUserMove(1) \n \
+   <Btn1Up>: HandleUserMove(0) \n \
    <Btn1Motion>: AnimateUserMove() \n \
    <Btn3Motion>: HandlePV() \n \
    <Btn3Up>: PieceMenuPopup(menuB) \n \
@@ -4651,6 +4652,7 @@ void HandleUserMove(w, event, prms, nprms)
      Cardinal *nprms;
 {
     if (w != boardWidget || errorExitStatus != -1) return;
+    if(nprms) shiftKey = !strcmp(prms[0], "1");
 
     if (promotionUp) {
 	if (event->type == ButtonPress) {
-- 
1.7.0.4