From 635daf56748af66bf3185d85fb83b12280ef6c83 Mon Sep 17 00:00:00 2001
From: H.G.Muller <hgm@hgm-xboard.(none)>
Date: Tue, 22 Mar 2016 14:56:10 +0100
Subject: [PATCH] Add -fen option

A volatile string option -fen can now be used to set the initial position
of the initial variant through the command line, removing the need to
prepare a position file for this. Otherwise the effect should be the same
as when using -lpf: New games will be started from the specifoed  positon
until the New Variant dialog is used. The position is 'auto-sizing', i.e.
the FEN is used to set the board geometry as well.
---
 args.h    |    1 +
 backend.c |    5 +++++
 common.h  |    1 +
 3 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/args.h b/args.h
index 866a6a9..a2f3b46 100644
--- a/args.h
+++ b/args.h
@@ -714,6 +714,7 @@ ArgDescriptor argDescriptors[] = {
   { "memoHeaders", ArgBoolean, (void *) &appData.headers, TRUE, (ArgIniType) FALSE },
   { "startupMessage", ArgString, (void *) &appData.message, FALSE, (ArgIniType) "" },
   { "messageSuppress", ArgString, (void *) &appData.suppress, XBOARD, (ArgIniType) "" },
+  { "fen", ArgString, (void *) &appData.fen, FALSE, (ArgIniType) "" },
 
 #if ZIPPY
   { "zippyTalk", ArgBoolean, (void *) &appData.zippyTalk, FALSE, (ArgIniType) ZIPPY_TALK },
diff --git a/backend.c b/backend.c
index e7cf5b2..c5be312 100644
--- a/backend.c
+++ b/backend.c
@@ -1743,6 +1743,11 @@ InitBackEnd3 P((void))
                 CopyBoard(filePosition, boards[0]);
                 CopyBoard(initialPosition, boards[0]);
             }
+	} else if(*appData.fen != NULLCHAR) {
+	    if(ParseFEN(filePosition, &blackPlaysFirst, appData.fen, TRUE) && !blackPlaysFirst) {
+                startedFromPositionFile = TRUE;
+		Reset(TRUE, TRUE);
+	    }
 	}
 	if (initialMode == AnalyzeMode) {
 	  if (appData.noChessProgram) {
diff --git a/common.h b/common.h
index c98ba91..6c2a60f 100644
--- a/common.h
+++ b/common.h
@@ -800,6 +800,7 @@ typedef struct {
     char *recentEngineList;
     char *message;
     char *suppress;
+    char *fen;
     char *tourneyFile;
     char *defName;
     char *processes;
-- 
1.7.0.4