# HG changeset patch
# User Bram Moolenaar <bram@vim.org>
# Date 1422380656 -3600
# Node ID c1ed973fb58faa650dcd4d25a98c669edb8ca0d4
# Parent  35e6873f13a02792908f8ed381840d4444410b2c
updated for version 7.4.605
Problem:    The # register is not writable, it cannot be restored after
	    jumping around.
Solution:   Make the # register writable. (Marcin Szamotulski)

diff --git a/runtime/doc/change.txt b/runtime/doc/change.txt
--- a/runtime/doc/change.txt
+++ b/runtime/doc/change.txt
@@ -1,4 +1,4 @@
-*change.txt*    For Vim version 7.4.  Last change: 2014 Jun 26
+*change.txt*    For Vim version 7.4.  Last change: 2015 Jan 27
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -1103,11 +1103,12 @@ 1. The unnamed register ""
 2. 10 numbered registers "0 to "9
 3. The small delete register "-
 4. 26 named registers "a to "z or "A to "Z
-5. four read-only registers ":, "., "% and "#
-6. the expression register "=
-7. The selection and drop registers "*, "+ and "~ 
-8. The black hole register "_
-9. Last search pattern register "/
+5. three read-only registers ":, "., "%
+7. alternate buffer register "#
+7. the expression register "=
+8. The selection and drop registers "*, "+ and "~ 
+9. The black hole register "_
+10. Last search pattern register "/
 
 1. Unnamed register ""				*quote_quote* *quotequote*
 Vim fills this register with text deleted with the "d", "c", "s", "x" commands
@@ -1153,7 +1154,7 @@ letters to replace their previous conten
 to their previous contents.  When the '>' flag is present in 'cpoptions' then
 a line break is inserted before the appended text.
 
-5. Read-only registers ":, "., "% and "#
+5. Read-only registers ":, ". and "%
 These are '%', '#', ':' and '.'.  You can use them only with the "p", "P",
 and ":put" commands and with CTRL-R.  {not in Vi}
 						*quote_.* *quote.* *E29*
@@ -1164,8 +1165,6 @@ and ":put" commands and with CTRL-R.  {n
 		('textwidth' and other options affect what is inserted).
 							*quote_%* *quote%*
 	"%	Contains the name of the current file.
-							*quote_#* *quote#*
-	"#	Contains the name of the alternate file.
 						*quote_:* *quote:* *E30*
 	":	Contains the most recent executed command-line.  Example: Use
 		"@:" to repeat the previous command-line command.
@@ -1174,8 +1173,23 @@ and ":put" commands and with CTRL-R.  {n
 		the command was completely from a mapping.
 		{not available when compiled without the |+cmdline_hist|
 		feature}
+							*quote_#* *quote#*
+6. Alternate file register "#
+Contains the name of the alternate file for the current window.  It will
+change how the |CTRL-^| command works.
+This register is writable, mainly to allow for restoring it after a plugin has
+changed it.  It accepts buffer number: >
+    let altbuf = bufnr(@#)
+    ...
+    let @# = altbuf
+It will give error |E86| if you pass buffer number and this buffer does not
+exist.
+It can also accept a match with an existing buffer name: >
+    let @# = 'buffer_name'
+Error |E93| if there is more than one buffer matching the given name or |E94|
+if none of buffers matches the given name.
 
-6. Expression register "=			*quote_=* *quote=* *@=*
+7. Expression register "=			*quote_=* *quote=* *@=*
 This is not really a register that stores text, but is a way to use an
 expression in commands which use a register.  The expression register is
 read-only; you cannot put text into it.  After the '=', the cursor moves to
@@ -1196,7 +1210,7 @@ If the "= register is used for the "p" c
 characters.  If the String ends in a <NL>, it is regarded as a linewise
 register.  {not in Vi}
 
-7. Selection and drop registers "*, "+ and "~ 
+8. Selection and drop registers "*, "+ and "~ 
 Use these registers for storing and retrieving the selected text for the GUI.
 See |quotestar| and |quoteplus|.  When the clipboard is not available or not
 working, the unnamed register is used instead.  For Unix systems the clipboard
@@ -1218,12 +1232,12 @@ GTK GUI}
 Note: The "~ register is only used when dropping plain text onto Vim.
 Drag'n'drop of URI lists is handled internally.
 
-8. Black hole register "_				*quote_*
+9. Black hole register "_				*quote_*
 When writing to this register, nothing happens.  This can be used to delete
 text without affecting the normal registers.  When reading from this register,
 nothing is returned.  {not in Vi}
 
-9. Last search pattern register	"/			*quote_/* *quote/*
+10. Last search pattern register	"/			*quote_/* *quote/*
 Contains the most recent search-pattern.  This is used for "n" and 'hlsearch'.
 It is writable with `:let`, you can change it to have 'hlsearch' highlight
 other matches without actually searching.  You can't yank or delete into this
diff --git a/src/buffer.c b/src/buffer.c
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1150,7 +1150,7 @@ do_buffer(action, start, dir, count, for
 	{
 	    /* don't warn when deleting */
 	    if (!unload)
-		EMSGN(_("E86: Buffer %ld does not exist"), count);
+		EMSGN(_(e_nobufnr), count);
 	}
 	else if (dir == FORWARD)
 	    EMSG(_("E87: Cannot go beyond last buffer"));
diff --git a/src/globals.h b/src/globals.h
--- a/src/globals.h
+++ b/src/globals.h
@@ -1571,6 +1571,7 @@ EXTERN char_u e_nbreadonly[]	INIT(= N_("
 EXTERN char_u e_intern2[]	INIT(= N_("E685: Internal error: %s"));
 EXTERN char_u e_maxmempat[]	INIT(= N_("E363: pattern uses more memory than 'maxmempattern'"));
 EXTERN char_u e_emptybuf[]	INIT(= N_("E749: empty buffer"));
+EXTERN char_u e_nobufnr[]	INIT(= N_("E86: Buffer %ld does not exist"));
 
 #ifdef FEAT_EX_EXTRA
 EXTERN char_u e_invalpat[]	INIT(= N_("E682: Invalid search pattern or delimiter"));
diff --git a/src/ops.c b/src/ops.c
--- a/src/ops.c
+++ b/src/ops.c
@@ -856,11 +856,12 @@ valid_yank_reg(regname, writing)
     if (       (regname > 0 && ASCII_ISALNUM(regname))
 	    || (!writing && vim_strchr((char_u *)
 #ifdef FEAT_EVAL
-				    "/.%#:="
+				    "/.%:="
 #else
-				    "/.%#:"
+				    "/.%:"
 #endif
 					, regname) != NULL)
+	    || regname == '#'
 	    || regname == '"'
 	    || regname == '-'
 	    || regname == '_'
@@ -6514,6 +6515,27 @@ write_reg_contents_ex(name, str, maxlen,
 	return;
     }
 
+    if (name == '#')
+    {
+	buf_T	*buf;
+
+	if (VIM_ISDIGIT(*str))
+	{
+	    int	num = atoi((char *)str);
+
+	    buf = buflist_findnr(num);
+	    if (buf == NULL)
+		EMSGN(_(e_nobufnr), (long)num);
+	}
+	else
+	    buf = buflist_findnr(buflist_findpat(str, str + STRLEN(str),
+							 TRUE, FALSE, FALSE));
+	if (buf == NULL)
+	    return;
+	curwin->w_alt_fnum = buf->b_fnum;
+	return;
+    }
+
 #ifdef FEAT_EVAL
     if (name == '=')
     {
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    605,
+/**/
     604,
 /**/
     603,