Merge from mainline.

762f8d96 · Paul Eggert · eb3f1cc8 · 8546720e · 762f8d96 · 762f8d96
Commit 762f8d96 authored Apr 09, 2011 by Paul Eggert
59 changed files
--- a/ChangeLog
+++ b/ChangeLog
-2011-04-08  Paul Eggert  <eggert@cs.ucla.edu>
+2011-04-09  Paul Eggert  <eggert@cs.ucla.edu>

 	* lib/allocator.c: New file, automatically generated by gnulib.

+2011-04-07  Glenn Morris  <rgm@gnu.org>
+
+	* autogen/update_autogen: Ignore comment diffs in ldefs-boot.el.
+
 2011-04-06  Eli Zaretskii  <eliz@gnu.org>

 	* lib/makefile.w32-in ($(BLD)/careadlinkat.$(O), GNULIBOBJS):

--- a/autogen/aclocal.m4
+++ b/autogen/aclocal.m4
@@ -13,8 +13,8 @@

 m4_ifndef([AC_AUTOCONF_VERSION],
  [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
-m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.68],,
-[m4_warning([this file was generated for autoconf 2.68.
+m4_if(m4_defn([AC_AUTOCONF_VERSION]), [2.65],,
+[m4_warning([this file was generated for autoconf 2.65.
 You have another version of autoconf.  It may work, but is not guaranteed to.
 If you have problems, you may need to regenerate the build system entirely.
 To do so, use the procedure documented by the package, typically `autoreconf'.])])

--- a/autogen/config.guess
+++ b/autogen/config.guess
@@ -4,7 +4,7 @@
 #   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
 #   Free Software Foundation, Inc.

-timestamp='2009-11-20'
+timestamp='2009-06-10'

 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -27,16 +27,16 @@ timestamp='2009-11-20'
 # the same distribution terms that you use for the rest of that program.


-# Originally written by Per Bothner.  Please send patches (context
-# diff format) to <config-patches@gnu.org> and include a ChangeLog
-# entry.
+# Originally written by Per Bothner <per@bothner.com>.
+# Please send patches to <config-patches@gnu.org>.  Submit a context
+# diff and a properly formatted ChangeLog entry.
 #
 # This script attempts to guess a canonical system name similar to
 # config.sub.  If it succeeds, it prints the system name on stdout, and
 # exits with 0.  Otherwise, it exits with 1.
 #
-# You can get the latest version of this script from:
-# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess;hb=HEAD
+# The plan is that this can be called by configure scripts if you
+# don't specify an explicit build system type.

 me=`echo "$0" | sed -e 's,.*/,,'`

@@ -333,9 +333,6 @@ case "${UNAME_MACHINE}:${UNAME_SYSTEM}:${UNAME_RELEASE}:${UNAME_VERSION}" in
    sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
 	echo sparc-sun-solaris2`echo ${UNAME_RELEASE}|sed -e 's/[^.]*//'`
 	exit ;;
-    i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
-	echo i386-pc-auroraux${UNAME_RELEASE}
-	exit ;;
    i86pc:SunOS:5.*:* | i86xen:SunOS:5.*:*)
 	eval $set_cc_for_build
 	SUN_ARCH="i386"
@@ -810,12 +807,12 @@ EOF
    i*:PW*:*)
 	echo ${UNAME_MACHINE}-pc-pw32
 	exit ;;
-    *:Interix*:*)
+    *:Interix*:[3456]*)
    	case ${UNAME_MACHINE} in
 	    x86)
 		echo i586-pc-interix${UNAME_RELEASE}
 		exit ;;
-	    authenticamd | genuineintel | EM64T)
+	    EM64T | authenticamd | genuineintel)
 		echo x86_64-unknown-interix${UNAME_RELEASE}
 		exit ;;
 	    IA64)
@@ -857,20 +854,6 @@ EOF
    i*86:Minix:*:*)
 	echo ${UNAME_MACHINE}-pc-minix
 	exit ;;
-    alpha:Linux:*:*)
-	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
-	  EV5)   UNAME_MACHINE=alphaev5 ;;
-	  EV56)  UNAME_MACHINE=alphaev56 ;;
-	  PCA56) UNAME_MACHINE=alphapca56 ;;
-	  PCA57) UNAME_MACHINE=alphapca56 ;;
-	  EV6)   UNAME_MACHINE=alphaev6 ;;
-	  EV67)  UNAME_MACHINE=alphaev67 ;;
-	  EV68*) UNAME_MACHINE=alphaev68 ;;
-        esac
-	objdump --private-headers /bin/sh | grep -q ld.so.1
-	if test "$?" = 0 ; then LIBC="libc1" ; else LIBC="" ; fi
-	echo ${UNAME_MACHINE}-unknown-linux-gnu${LIBC}
-	exit ;;
    arm*:Linux:*:*)
 	eval $set_cc_for_build
 	if echo __ARM_EABI__ | $CC_FOR_BUILD -E - 2>/dev/null \
@@ -893,17 +876,6 @@ EOF
    frv:Linux:*:*)
    	echo frv-unknown-linux-gnu
 	exit ;;
-    i*86:Linux:*:*)
-	LIBC=gnu
-	eval $set_cc_for_build
-	sed 's/^	//' << EOF >$dummy.c
-	#ifdef __dietlibc__
-	LIBC=dietlibc
-	#endif
-EOF
-	eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^LIBC'`
-	echo "${UNAME_MACHINE}-pc-linux-${LIBC}"
-	exit ;;
    ia64:Linux:*:*)
 	echo ${UNAME_MACHINE}-unknown-linux-gnu
 	exit ;;
@@ -929,18 +901,39 @@ EOF
 	#endif
 	#endif
 EOF
-	eval `$CC_FOR_BUILD -E $dummy.c 2>/dev/null | grep '^CPU'`
+	eval "`$CC_FOR_BUILD -E $dummy.c 2>/dev/null | sed -n '
+	    /^CPU/{
+		s: ::g
+		p
+	    }'`"
 	test x"${CPU}" != x && { echo "${CPU}-unknown-linux-gnu"; exit; }
 	;;
    or32:Linux:*:*)
 	echo or32-unknown-linux-gnu
 	exit ;;
+    ppc:Linux:*:*)
+	echo powerpc-unknown-linux-gnu
+	exit ;;
+    ppc64:Linux:*:*)
+	echo powerpc64-unknown-linux-gnu
+	exit ;;
+    alpha:Linux:*:*)
+	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
+	  EV5)   UNAME_MACHINE=alphaev5 ;;
+	  EV56)  UNAME_MACHINE=alphaev56 ;;
+	  PCA56) UNAME_MACHINE=alphapca56 ;;
+	  PCA57) UNAME_MACHINE=alphapca56 ;;
+	  EV6)   UNAME_MACHINE=alphaev6 ;;
+	  EV67)  UNAME_MACHINE=alphaev67 ;;
+	  EV68*) UNAME_MACHINE=alphaev68 ;;
+        esac
+	objdump --private-headers /bin/sh | grep -q ld.so.1
+	if test "$?" = 0 ; then LIBC="libc1" ; else LIBC="" ; fi
+	echo ${UNAME_MACHINE}-unknown-linux-gnu${LIBC}
+	exit ;;
    padre:Linux:*:*)
 	echo sparc-unknown-linux-gnu
 	exit ;;
-    parisc64:Linux:*:* | hppa64:Linux:*:*)
-	echo hppa64-unknown-linux-gnu
-	exit ;;
    parisc:Linux:*:* | hppa:Linux:*:*)
 	# Look for CPU level
 	case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
@@ -949,11 +942,8 @@ EOF
 	  *)    echo hppa-unknown-linux-gnu ;;
 	esac
 	exit ;;
-    ppc64:Linux:*:*)
-	echo powerpc64-unknown-linux-gnu
-	exit ;;
-    ppc:Linux:*:*)
-	echo powerpc-unknown-linux-gnu
+    parisc64:Linux:*:* | hppa64:Linux:*:*)
+	echo hppa64-unknown-linux-gnu
 	exit ;;
    s390:Linux:*:* | s390x:Linux:*:*)
 	echo ${UNAME_MACHINE}-ibm-linux
@@ -976,6 +966,58 @@ EOF
    xtensa*:Linux:*:*)
    	echo ${UNAME_MACHINE}-unknown-linux-gnu
 	exit ;;
+    i*86:Linux:*:*)
+	# The BFD linker knows what the default object file format is, so
+	# first see if it will tell us. cd to the root directory to prevent
+	# problems with other programs or directories called `ld' in the path.
+	# Set LC_ALL=C to ensure ld outputs messages in English.
+	ld_supported_targets=`cd /; LC_ALL=C ld --help 2>&1 \
+			 | sed -ne '/supported targets:/!d
+				    s/[ 	][ 	]*/ /g
+				    s/.*supported targets: *//
+				    s/ .*//
+				    p'`
+        case "$ld_supported_targets" in
+	  elf32-i386)
+		TENTATIVE="${UNAME_MACHINE}-pc-linux-gnu"
+		;;
+	esac
+	# Determine whether the default compiler is a.out or elf
+	eval $set_cc_for_build
+	sed 's/^	//' << EOF >$dummy.c
+	#include <features.h>
+	#ifdef __ELF__
+	# ifdef __GLIBC__
+	#  if __GLIBC__ >= 2
+	LIBC=gnu
+	#  else
+	LIBC=gnulibc1
+	#  endif
+	# else
+	LIBC=gnulibc1
+	# endif
+	#else
+	#if defined(__INTEL_COMPILER) || defined(__PGI) || defined(__SUNPRO_C) || defined(__SUNPRO_CC)
+	LIBC=gnu
+	#else
+	LIBC=gnuaout
+	#endif
+	#endif
+	#ifdef __dietlibc__
+	LIBC=dietlibc
+	#endif
+EOF
+	eval "`$CC_FOR_BUILD -E $dummy.c 2>/dev/null | sed -n '
+	    /^LIBC/{
+		s: ::g
+		p
+	    }'`"
+	test x"${LIBC}" != x && {
+		echo "${UNAME_MACHINE}-pc-linux-${LIBC}"
+		exit
+	}
+	test x"${TENTATIVE}" != x && { echo "${TENTATIVE}"; exit; }
+	;;
    i*86:DYNIX/ptx:4*:*)
 	# ptx 4.0 does uname -s correctly, with DYNIX/ptx in there.
 	# earlier versions are messed up and put the nodename in both
@@ -1205,16 +1247,6 @@ EOF
    *:Darwin:*:*)
 	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
 	case $UNAME_PROCESSOR in
-	    i386)
-		eval $set_cc_for_build
-		if [ "$CC_FOR_BUILD" != 'no_compiler_found' ]; then
-		  if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
-		      (CCOPTS= $CC_FOR_BUILD -E - 2>/dev/null) | \
-		      grep IS_64BIT_ARCH >/dev/null
-		  then
-		      UNAME_PROCESSOR="x86_64"
-		  fi
-		fi ;;
 	    unknown) UNAME_PROCESSOR=powerpc ;;
 	esac
 	echo ${UNAME_PROCESSOR}-apple-darwin${UNAME_RELEASE}

--- a/autogen/config.in
+++ b/autogen/config.in
@@ -1209,9 +1209,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 # define __restrict__
 #endif

-/* Define to `unsigned int' if <sys/types.h> does not define. */
-#undef size_t
-
 /* type to use in place of socklen_t if not defined */
 #undef socklen_t


--- a/autogen/config.sub
+++ b/autogen/config.sub
@@ -4,7 +4,7 @@
 #   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
 #   Free Software Foundation, Inc.

-timestamp='2009-11-20'
+timestamp='2009-06-11'

 # This file is (in principle) common to ALL GNU software.
 # The presence of a machine in this file suggests that SOME GNU software
@@ -32,16 +32,13 @@ timestamp='2009-11-20'


 # Please send patches to <config-patches@gnu.org>.  Submit a context
-# diff and a properly formatted GNU ChangeLog entry.
+# diff and a properly formatted ChangeLog entry.
 #
 # Configuration subroutine to validate and canonicalize a configuration type.
 # Supply the specified configuration type as an argument.
 # If it is invalid, we print an error message on stderr and exit with code 1.
 # Otherwise, we print the canonical config type on stdout and succeed.

-# You can get the latest version of this script from:
-# http://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub;hb=HEAD
-
 # This file is supposed to be the same for all GNU packages
 # and recognize all the CPU types, system types and aliases
 # that are meaningful with *any* GNU software.
@@ -152,7 +149,7 @@ case $os in
 	-convergent* | -ncr* | -news | -32* | -3600* | -3100* | -hitachi* |\
 	-c[123]* | -convex* | -sun | -crds | -omron* | -dg | -ultra | -tti* | \
 	-harris | -dolphin | -highlevel | -gould | -cbm | -ns | -masscomp | \
-	-apple | -axis | -knuth | -cray | -microblaze)
+	-apple | -axis | -knuth | -cray)
 		os=
 		basic_machine=$1
 		;;
@@ -287,7 +284,6 @@ case $basic_machine in
 	| pdp10 | pdp11 | pj | pjl \
 	| powerpc | powerpc64 | powerpc64le | powerpcle | ppcbe \
 	| pyramid \
-	| rx \
 	| score \
 	| sh | sh[1234] | sh[24]a | sh[24]aeb | sh[23]e | sh[34]eb | sheb | shbe | shle | sh[1234]le | sh3ele \
 	| sh64 | sh64le \
@@ -295,14 +291,13 @@ case $basic_machine in
 	| sparcv8 | sparcv9 | sparcv9b | sparcv9v \
 	| spu | strongarm \
 	| tahoe | thumb | tic4x | tic80 | tron \
-	| ubicom32 \
 	| v850 | v850e \
 	| we32k \
 	| x86 | xc16x | xscale | xscalee[bl] | xstormy16 | xtensa \
 	| z8k | z80)
 		basic_machine=$basic_machine-unknown
 		;;
-	m6811 | m68hc11 | m6812 | m68hc12 | picochip)
+	m6811 | m68hc11 | m6812 | m68hc12)
 		# Motorola 68HC11/12.
 		basic_machine=$basic_machine-unknown
 		os=-none
@@ -345,7 +340,7 @@ case $basic_machine in
 	| lm32-* \
 	| m32c-* | m32r-* | m32rle-* \
 	| m68000-* | m680[012346]0-* | m68360-* | m683?2-* | m68k-* \
-	| m88110-* | m88k-* | maxq-* | mcore-* | metag-* | microblaze-* \
+	| m88110-* | m88k-* | maxq-* | mcore-* | metag-* \
 	| mips-* | mipsbe-* | mipseb-* | mipsel-* | mipsle-* \
 	| mips16-* \
 	| mips64-* | mips64el-* \
@@ -373,7 +368,7 @@ case $basic_machine in
 	| pdp10-* | pdp11-* | pj-* | pjl-* | pn-* | power-* \
 	| powerpc-* | powerpc64-* | powerpc64le-* | powerpcle-* | ppcbe-* \
 	| pyramid-* \
-	| romp-* | rs6000-* | rx-* \
+	| romp-* | rs6000-* \
 	| sh-* | sh[1234]-* | sh[24]a-* | sh[24]aeb-* | sh[23]e-* | sh[34]eb-* | sheb-* | shbe-* \
 	| shle-* | sh[1234]le-* | sh3ele-* | sh64-* | sh64le-* \
 	| sparc-* | sparc64-* | sparc64b-* | sparc64v-* | sparc86x-* | sparclet-* \
@@ -382,7 +377,6 @@ case $basic_machine in
 	| tahoe-* | thumb-* \
 	| tic30-* | tic4x-* | tic54x-* | tic55x-* | tic6x-* | tic80-* | tile-* \
 	| tron-* \
-	| ubicom32-* \
 	| v850-* | v850e-* | vax-* \
 	| we32k-* \
 	| x86-* | x86_64-* | xc16x-* | xps100-* | xscale-* | xscalee[bl]-* \
@@ -732,9 +726,6 @@ case $basic_machine in
 		basic_machine=ns32k-utek
 		os=-sysv
 		;;
-        microblaze)
-		basic_machine=microblaze-xilinx
-		;;
 	mingw32)
 		basic_machine=i386-pc
 		os=-mingw32
@@ -1256,9 +1247,6 @@ case $os in
        # First match some system type aliases
        # that might get confused with valid system types.
 	# -solaris* is a basic system type, with this one exception.
-        -auroraux)
-	        os=-auroraux
-		;;
 	-solaris1 | -solaris1.*)
 		os=`echo $os | sed -e 's|solaris1|sunos4|'`
 		;;
@@ -1280,8 +1268,8 @@ case $os in
 	# -sysv* is not here because it comes later, after sysvr4.
 	-gnu* | -bsd* | -mach* | -minix* | -genix* | -ultrix* | -irix* \
 	      | -*vms* | -sco* | -esix* | -isc* | -aix* | -cnk* | -sunos | -sunos[34]*\
-	      | -hpux* | -unos* | -osf* | -luna* | -dgux* | -auroraux* | -solaris* \
-	      | -sym* | -kopensolaris* \
+	      | -hpux* | -unos* | -osf* | -luna* | -dgux* | -solaris* | -sym* \
+	      | -kopensolaris* \
 	      | -amigaos* | -amigados* | -msdos* | -newsos* | -unicos* | -aof* \
 	      | -aos* | -aros* \
 	      | -nindy* | -vxsim* | -vxworks* | -ebmon* | -hms* | -mvs* \
@@ -1302,7 +1290,7 @@ case $os in
 	      | -os2* | -vos* | -palmos* | -uclinux* | -nucleus* \
 	      | -morphos* | -superux* | -rtmk* | -rtmk-nova* | -windiss* \
 	      | -powermax* | -dnix* | -nx6 | -nx7 | -sei* | -dragonfly* \
-	      | -skyos* | -haiku* | -rdos* | -toppers* | -drops* | -es*)
+	      | -skyos* | -haiku* | -rdos* | -toppers* | -drops*)
 	# Remember, each alternative MUST END IN *, to match a version number.
 		;;
 	-qnx*)

--- a/autogen/configure
+++ b/autogen/configure
--- a/autogen/update_autogen
+++ b/autogen/update_autogen
@@ -268,7 +268,10 @@ echo "Running lisp/ make..."
 make -C lisp "$@" autoloads EMACS=../src/bootstrap-emacs || die "make src error"


-[ ! "$lboot_flag" ] || cp $ldefs_in $ldefs_out || die "cp ldefs_boot error"
+## Ignore comment differences.
+[ ! "$lboot_flag" ] || \
+    diff -q -I '^;' $ldefs_in $ldefs_out || \
+    cp $ldefs_in $ldefs_out || die "cp ldefs_boot error"


 cd lisp

--- a/doc/emacs/ChangeLog
+++ b/doc/emacs/ChangeLog
+2011-03-26  Chong Yidong  <cyd@stupidchicken.com>
+
+	* display.texi (Auto Scrolling): Fix scroll-up/scroll-down confusion.
+
 2011-03-30  Eli Zaretskii  <eliz@gnu.org>

 	* display.texi (Auto Scrolling): Document the limit of 100 lines

--- a/doc/emacs/display.texi
+++ b/doc/emacs/display.texi
@@ -206,16 +206,18 @@ how aggressively it scrolls by setting the variables
 @code{scroll-up-aggressively} and @code{scroll-down-aggressively}.
 The value of @code{scroll-up-aggressively} should be either
 @code{nil}, or a fraction @var{f} between 0 and 1.  A fraction
-specifies where on the screen to put point when scrolling upward: when
-a window scrolls up because point is above the window start, the new
+specifies where on the screen to put point when scrolling upward,
+i.e.@: when point moves forward in the buffer, and therefore text
+scrolls up in the window.  When point goes off the window end, the new
 start position is chosen to put point @var{f} parts of the window
-height from the top.  Thus, larger @var{f} means more aggressive
-scrolling.  The default value, @code{nil}, is equivalent to 0.5.
+height from the bottom.  Thus, larger @var{f} means more aggressive
+scrolling: more new text is brought into view.  The default value,
+@code{nil}, is equivalent to 0.5.

  Likewise, @code{scroll-down-aggressively} is used for scrolling
-down.  The value specifies how far point should be placed from the
-bottom of the window; thus, as with @code{scroll-up-aggressively}, a
-larger value is more aggressive.
+down, i.e.@: moving point back in the buffer.  The value specifies how
+far point should be placed from the top of the window; thus, as with
+@code{scroll-up-aggressively}, a larger value is more aggressive.

  These two variables are ignored if either @code{scroll-step} or
 @code{scroll-conservatively} are set to a non-zero value.

--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
+2011-03-21  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+	* minibuf.texi (Basic Completion): Be a bit more precise about the
+	valid kinds of completion tables.
+	(Programmed Completion): Remove obsolete text about lambda expressions
+	not being valid completion tables.
+
+2011-03-19  Chong Yidong  <cyd@stupidchicken.com>
+
+	* positions.texi (Excursions): Explain the "save-excursion
+	defeated by set-buffer" warning.
+
+	* buffers.texi (Current Buffer): Copyedits.  Don't recommend using
+	save-excursion.  Suggested by Uday S Reddy.
+
 2011-04-01  Stefan Monnier  <monnier@iro.umontreal.ca>

 	* variables.texi (Defining Variables): Mention the new meaning of `defvar'.

--- a/doc/lispref/buffers.texi
+++ b/doc/lispref/buffers.texi
@@ -85,43 +85,63 @@ This function returns @code{t} if @var{object} is a buffer,
 @cindex changing to another buffer
 @cindex current buffer

-  There are, in general, many buffers in an Emacs session.  At any time,
-one of them is designated as the @dfn{current buffer}.  This is the
-buffer in which most editing takes place, because most of the primitives
-for examining or changing text in a buffer operate implicitly on the
-current buffer (@pxref{Text}).  Normally the buffer that is displayed on
-the screen in the selected window is the current buffer, but this is not
-always so: a Lisp program can temporarily designate any buffer as
-current in order to operate on its contents, without changing what is
-displayed on the screen.
-
-  The way to designate a current buffer in a Lisp program is by calling
-@code{set-buffer}.  The specified buffer remains current until a new one
-is designated.
-
-  When an editing command returns to the editor command loop, the
-command loop designates the buffer displayed in the selected window as
-current, to prevent confusion: the buffer that the cursor is in when
-Emacs reads a command is the buffer that the command will apply to.
-(@xref{Command Loop}.)  Therefore, @code{set-buffer} is not the way to
-switch visibly to a different buffer so that the user can edit it.  For
-that, you must use the functions described in @ref{Displaying Buffers}.
-
-  @strong{Warning:} Lisp functions that change to a different current buffer
-should not depend on the command loop to set it back afterwards.
-Editing commands written in Emacs Lisp can be called from other programs
-as well as from the command loop; it is convenient for the caller if
-the subroutine does not change which buffer is current (unless, of
-course, that is the subroutine's purpose).  Therefore, you should
-normally use @code{set-buffer} within a @code{save-current-buffer} or
-@code{save-excursion} (@pxref{Excursions}) form that will restore the
-current buffer when your function is done.  Here, as an example, is a
+  There are, in general, many buffers in an Emacs session.  At any
+time, one of them is designated the @dfn{current buffer}---the buffer
+in which most editing takes place.  Most of the primitives for
+examining or changing text operate implicitly on the current buffer
+(@pxref{Text}).
+
+  Normally, the buffer displayed in the selected window is the current
+buffer, but this is not always so: a Lisp program can temporarily
+designate any buffer as current in order to operate on its contents,
+without changing what is displayed on the screen.  The most basic
+function for designating a current buffer is @code{set-buffer}.
+
+@defun current-buffer
+This function returns the current buffer.
+
+@example
+@group
+(current-buffer)
+     @result{} #<buffer buffers.texi>
+@end group
+@end example
+@end defun
+
+@defun set-buffer buffer-or-name
+This function makes @var{buffer-or-name} the current buffer.
+@var{buffer-or-name} must be an existing buffer or the name of an
+existing buffer.  The return value is the buffer made current.
+
+This function does not display the buffer in any window, so the user
+cannot necessarily see the buffer.  But Lisp programs will now operate
+on it.
+@end defun
+
+  When an editing command returns to the editor command loop, Emacs
+automatically calls @code{set-buffer} on the buffer shown in the
+selected window.  This is to prevent confusion: it ensures that the
+buffer that the cursor is in, when Emacs reads a command, is the
+buffer to which that command applies (@pxref{Command Loop}).  Thus,
+you should not use @code{set-buffer} to switch visibly to a different
+buffer; for that, use the functions described in @ref{Displaying
+Buffers}.
+
+  When writing a Lisp function, do @emph{not} rely on this behavior of
+the command loop to restore the current buffer after an operation.
+Editing commands can also be called as Lisp functions by other
+programs, not just from the command loop; it is convenient for the
+caller if the subroutine does not change which buffer is current
+(unless, of course, that is the subroutine's purpose).
+
+  To operate temporarily on another buffer, put the @code{set-buffer}
+within a @code{save-current-buffer} form.  Here, as an example, is a
 simplified version of the command @code{append-to-buffer}:

 @example
 @group
 (defun append-to-buffer (buffer start end)
-  "Append to specified buffer the text of the region."
+  "Append the text of the region to BUFFER."
  (interactive "BAppend to buffer: \nr")
  (let ((oldbuf (current-buffer)))
    (save-current-buffer
@@ -131,27 +151,36 @@ simplified version of the command @code{append-to-buffer}:
 @end example

 @noindent
-This function binds a local variable to record the current buffer, and
-then @code{save-current-buffer} arranges to make it current again.
-Next, @code{set-buffer} makes the specified buffer current.  Finally,
+Here, we bind a local variable to record the current buffer, and then
+@code{save-current-buffer} arranges to make it current again later.
+Next, @code{set-buffer} makes the specified buffer current, and
 @code{insert-buffer-substring} copies the string from the original
-current buffer to the specified (and now current) buffer.
-
-  If the buffer appended to happens to be displayed in some window,
-the next redisplay will show how its text has changed.  Otherwise, you
-will not see the change immediately on the screen.  The buffer becomes
-current temporarily during the execution of the command, but this does
-not cause it to be displayed.
-
-  If you make local bindings (with @code{let} or function arguments) for
-a variable that may also have buffer-local bindings, make sure that the
-same buffer is current at the beginning and at the end of the local
-binding's scope.  Otherwise you might bind it in one buffer and unbind
-it in another!  There are two ways to do this.  In simple cases, you may
-see that nothing ever changes the current buffer within the scope of the
-binding.  Otherwise, use @code{save-current-buffer} or
-@code{save-excursion} to make sure that the buffer current at the
-beginning is current again whenever the variable is unbound.
+buffer to the specified (and now current) buffer.
+
+  Alternatively, we can use the @code{with-current-buffer} macro:
+
+@example
+@group
+(defun append-to-buffer (buffer start end)
+  "Append the text of the region to BUFFER."
+  (interactive "BAppend to buffer: \nr")
+  (let ((oldbuf (current-buffer)))
+    (with-current-buffer (get-buffer-create buffer)
+      (insert-buffer-substring oldbuf start end))))
+@end group
+@end example
+
+  In either case, if the buffer appended to happens to be displayed in
+some window, the next redisplay will show how its text has changed.
+If it is not displayed in any window, you will not see the change
+immediately on the screen.  The command causes the buffer to become
+current temporarily, but does not cause it to be displayed.
+
+  If you make local bindings (with @code{let} or function arguments)
+for a variable that may also have buffer-local bindings, make sure
+that the same buffer is current at the beginning and at the end of the
+local binding's scope.  Otherwise you might bind it in one buffer and
+unbind it in another!

  Do not rely on using @code{set-buffer} to change the current buffer
 back, because that won't do the job if a quit happens while the wrong
@@ -168,29 +197,9 @@ have been wrong to do this:
 @end example

 @noindent
-Using @code{save-current-buffer}, as we did, handles quitting, errors,
-and @code{throw}, as well as ordinary evaluation.
-
-@defun current-buffer
-This function returns the current buffer.
-
-@example
-@group
-(current-buffer)
-     @result{} #<buffer buffers.texi>
-@end group
-@end example