patch 8.2.1262: src/ex_cmds.c file is too bigv8.2.1262

Problem:    src/ex_cmds.c file is too big.
Solution:   Move help related code to src/help.c. (Yegappan Lakshmanan,
            closes #6506)

13 files changed, 1342 insertions, 1346 deletions

diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 157dc94956..3e8bb04e0f 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -744,6 +744,7 @@ OBJ = \
 	$(OUTDIR)/gui_xim.o \
 	$(OUTDIR)/hardcopy.o \
 	$(OUTDIR)/hashtab.o \
+	$(OUTDIR)/help.o \
 	$(OUTDIR)/highlight.o \
 	$(OUTDIR)/if_cscope.o \
 	$(OUTDIR)/indent.o \
diff --git a/src/Make_morph.mak b/src/Make_morph.mak
index bd95115a39..6fc50ed1fd 100644
--- a/src/Make_morph.mak
+++ b/src/Make_morph.mak
@@ -64,6 +64,7 @@ SRC =	arabic.c						\
 	gui_xim.c						\
 	hardcopy.c						\
 	hashtab.c						\
+	help.c							\
 	highlight.c						\
 	indent.c						\
 	insexpand.c						\
diff --git a/src/Make_mvc.mak b/src/Make_mvc.mak
index b1bb8836e0..65d530f359 100644
--- a/src/Make_mvc.mak
+++ b/src/Make_mvc.mak
@@ -766,6 +766,7 @@ OBJ = \
 	$(OUTDIR)\gui_xim.obj \
 	$(OUTDIR)\hardcopy.obj \
 	$(OUTDIR)\hashtab.obj \
+	$(OUTDIR)\help.obj \
 	$(OUTDIR)\highlight.obj \
 	$(OBJDIR)\if_cscope.obj \
 	$(OUTDIR)\indent.obj \
@@ -1608,6 +1609,8 @@ $(OUTDIR)/hardcopy.obj:	$(OUTDIR) hardcopy.c  $(INCL) version.h
 
 $(OUTDIR)/hashtab.obj:	$(OUTDIR) hashtab.c  $(INCL)
 
+$(OUTDIR)/help.obj:	$(OUTDIR) help.c  $(INCL)
+
 $(OUTDIR)/highlight.obj:	$(OUTDIR) highlight.c  $(INCL)
 
 $(OUTDIR)/indent.obj:	$(OUTDIR) indent.c  $(INCL)
@@ -1930,6 +1933,7 @@ proto.h: \
 	proto/gui_xim.pro \
 	proto/hardcopy.pro \
 	proto/hashtab.pro \
+	proto/help.pro \
 	proto/highlight.pro \
 	proto/indent.pro \
 	proto/insexpand.pro \
diff --git a/src/Make_vms.mms b/src/Make_vms.mms
index 78f9dab5db..0d80c0617b 100644
--- a/src/Make_vms.mms
+++ b/src/Make_vms.mms
@@ -337,6 +337,7 @@ SRC = \
 	gui_xim.c \
 	hardcopy.c \
 	hashtab.c \
+	help.c \
 	highlight.c \
 	if_cscope.c \
 	if_xcmdsrv.c \
@@ -450,6 +451,7 @@ OBJ = \
 	gui_xim.obj \
 	hardcopy.obj \
 	hashtab.obj \
+	help.obj \
 	highlight.obj \
 	if_cscope.obj \
 	if_mzsch.obj \
@@ -834,6 +836,10 @@ hashtab.obj : hashtab.c vim.h [.auto]config.h feature.h os_unix.h \
  ascii.h keymap.h term.h macros.h structs.h regexp.h \
  gui.h beval.h [.proto]gui_beval.pro option.h ex_cmds.h proto.h \
  globals.h
+help.obj : help.c vim.h [.auto]config.h feature.h os_unix.h \
+ ascii.h keymap.h term.h macros.h structs.h regexp.h \
+ gui.h beval.h [.proto]gui_beval.pro option.h ex_cmds.h proto.h \
+ globals.h
 highlight.obj : highlight.c vim.h [.auto]config.h feature.h os_unix.h \
  ascii.h keymap.h term.h macros.h structs.h regexp.h \
  gui.h beval.h [.proto]gui_beval.pro option.h ex_cmds.h proto.h \
diff --git a/src/Makefile b/src/Makefile
index 2b10024401..36635bdbf5 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -404,7 +404,7 @@ CClink = $(CC)
 # Use --with-luajit if you want to use LuaJIT instead of Lua.
 # Set PATH environment variable to find lua or luajit executable.
 # This requires at least "normal" features, "tiny" and "small" don't work.
-#CONF_OPT_LUA = --enable-luainterp
+CONF_OPT_LUA = --enable-luainterp
 #CONF_OPT_LUA = --enable-luainterp=dynamic
 #CONF_OPT_LUA = --enable-luainterp --with-luajit
 #CONF_OPT_LUA = --enable-luainterp=dynamic --with-luajit
@@ -447,10 +447,10 @@ CClink = $(CC)
 # dlopen(), dlsym(), dlclose(), i.e. pythonX.Y.so must be available
 # However, this may still cause problems, such as "import termios" failing.
 # Build two separate versions of Vim in that case.
-#CONF_OPT_PYTHON = --enable-pythoninterp
+CONF_OPT_PYTHON = --enable-pythoninterp
 #CONF_OPT_PYTHON = --enable-pythoninterp --with-python-command=python2.7
 #CONF_OPT_PYTHON = --enable-pythoninterp=dynamic
-#CONF_OPT_PYTHON3 = --enable-python3interp
+CONF_OPT_PYTHON3 = --enable-python3interp
 #CONF_OPT_PYTHON3 = --enable-python3interp --with-python3-command=python3.6
 #CONF_OPT_PYTHON3 = --enable-python3interp=dynamic
 
@@ -472,7 +472,7 @@ CClink = $(CC)
 
 # CSCOPE
 # Uncomment this when you want to include the Cscope interface.
-#CONF_OPT_CSCOPE = --enable-cscope
+CONF_OPT_CSCOPE = --enable-cscope
 
 # NETBEANS - NetBeans interface. Only works with Motif, GTK, and gnome.
 # Motif version must have XPM libraries (see |netbeans-xpm|).
@@ -540,7 +540,7 @@ CClink = $(CC)
 #CONF_OPT_FEAT = --with-features=small
 #CONF_OPT_FEAT = --with-features=normal
 #CONF_OPT_FEAT = --with-features=big
-#CONF_OPT_FEAT = --with-features=huge
+CONF_OPT_FEAT = --with-features=huge
 
 # COMPILED BY - For including a specific e-mail address for ":version".
 #CONF_OPT_COMPBY = "--with-compiledby=John Doe <JohnDoe@yahoo.com>"
@@ -614,7 +614,7 @@ CClink = $(CC)
 # Use this with GCC to check for mistakes, unused arguments, etc.
 # Note: If you use -Wextra and get warnings in GTK code about function
 #       parameters, you can add -Wno-cast-function-type
-#CFLAGS = -g -Wall -Wextra -Wshadow -Wmissing-prototypes -Wunreachable-code -Wno-cast-function-type -Wno-deprecated-declarations -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
+CFLAGS = -g -Wall -Wextra -Wshadow -Wmissing-prototypes -Wunreachable-code -Wno-cast-function-type -Wno-deprecated-declarations -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
 # Add -Wpedantic to find // comments and other C99 constructs.
 # Better disable Perl and Python to avoid a lot of warnings.
 #CFLAGS = -g -Wall -Wextra -Wshadow -Wmissing-prototypes -Wpedantic -Wunreachable-code -Wunused-result -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
@@ -709,7 +709,7 @@ SANITIZER_LIBS = $(SANITIZER_CFLAGS)
 # Configuration is in the .ccmalloc or ~/.ccmalloc file.
 # Doesn't work very well, since memory linked to from global variables
 # (in libraries) is also marked as leaked memory.
-#LEAK_CFLAGS = -DEXITFREE
+LEAK_CFLAGS = -DEXITFREE
 #LEAK_LIBS = -lccmalloc
 
 # Uncomment this line to have Vim call abort() when an internal error is
@@ -1639,6 +1639,7 @@ BASIC_SRC = \
 	gui_xim.c \
 	hardcopy.c \
 	hashtab.c \
+	help.c \
 	highlight.c \
 	if_cscope.c \
 	if_xcmdsrv.c \
@@ -1790,6 +1791,7 @@ OBJ_COMMON = \
 	objects/gui_xim.o \
 	objects/hardcopy.o \
 	objects/hashtab.o \
+	objects/help.o \
 	objects/highlight.o \
 	objects/if_cscope.o \
 	objects/if_xcmdsrv.o \
@@ -1958,6 +1960,7 @@ PRO_AUTO = \
 	gui_beval.pro \
 	hardcopy.pro \
 	hashtab.pro \
+	help.pro \
 	highlight.pro \
 	if_cscope.pro \
 	if_lua.pro \
@@ -3264,6 +3267,9 @@ objects/hardcopy.o: hardcopy.c
 objects/hashtab.o: hashtab.c
 	$(CCC) -o $@ hashtab.c
 
+objects/help.o: help.c
+	$(CCC) -o $@ help.c
+
 objects/gui.o: gui.c
 	$(CCC) -o $@ gui.c
 
@@ -3930,6 +3936,10 @@ objects/hashtab.o: hashtab.c vim.h protodef.h auto/config.h feature.h os_unix.h
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
  proto.h globals.h
+objects/help.o: help.c vim.h protodef.h auto/config.h feature.h os_unix.h \
+ auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
+ proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
+ proto.h globals.h
 objects/highlight.o: highlight.c vim.h protodef.h auto/config.h feature.h \
  os_unix.h auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
diff --git a/src/README.md b/src/README.md
index a196f2b954..f499c4cdb2 100644
--- a/src/README.md
+++ b/src/README.md
@@ -48,6 +48,7 @@ filepath.c	| dealing with file names and paths
 findfile.c	| search for files in 'path'
 fold.c		| folding
 getchar.c	| getting characters and key mapping
+help.c		| vim help related functions
 highlight.c	| syntax highlighting
 indent.c	| text indentation
 insexpand.c	| Insert mode completion
diff --git a/src/cmdexpand.c b/src/cmdexpand.c
index d92366c61e..a10fff8b3d 100644
--- a/src/cmdexpand.c
+++ b/src/cmdexpand.c
@@ -1887,62 +1887,6 @@ expand_cmdline(
     return EXPAND_OK;
 }
 
-#ifdef FEAT_MULTI_LANG
-/*
- * Cleanup matches for help tags:
- * Remove "@ab" if the top of 'helplang' is "ab" and the language of the first
- * tag matches it.  Otherwise remove "@en" if "en" is the only language.
- */
-    static void
-cleanup_help_tags(int num_file, char_u **file)
-{
-    int		i, j;
-    int		len;
-    char_u	buf[4];
-    char_u	*p = buf;
-
-    if (p_hlg[0] != NUL && (p_hlg[0] != 'e' || p_hlg[1] != 'n'))
-    {
-	*p++ = '@';
-	*p++ = p_hlg[0];
-	*p++ = p_hlg[1];
-    }
-    *p = NUL;
-
-    for (i = 0; i < num_file; ++i)
-    {
-	len = (int)STRLEN(file[i]) - 3;
-	if (len <= 0)
-	    continue;
-	if (STRCMP(file[i] + len, "@en") == 0)
-	{
-	    // Sorting on priority means the same item in another language may
-	    // be anywhere.  Search all items for a match up to the "@en".
-	    for (j = 0; j < num_file; ++j)
-		if (j != i && (int)STRLEN(file[j]) == len + 3
-			   && STRNCMP(file[i], file[j], len + 1) == 0)
-		    break;
-	    if (j == num_file)
-		// item only exists with @en, remove it
-		file[i][len] = NUL;
-	}
-    }
-
-    if (*buf != NUL)
-	for (i = 0; i < num_file; ++i)
-	{
-	    len = (int)STRLEN(file[i]) - 3;
-	    if (len <= 0)
-		continue;
-	    if (STRCMP(file[i] + len, buf) == 0)
-	    {
-		// remove the default language
-		file[i][len] = NUL;
-	    }
-	}
-}
-#endif
-
 /*
  * Function given to ExpandGeneric() to obtain the possible arguments of the
  * ":behave {mswin,xterm}" command.
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 11894f6387..59c562b917 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -23,8 +23,6 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char_u *cmd,
 static int not_writing(void);
 static int check_readonly(int *forceit, buf_T *buf);
 static void delbuf_msg(char_u *name);
-static int help_compare(const void *s1, const void *s2);
-static void prepare_help_buffer(void);
 
 /*
  * ":ascii" and "ga".
@@ -5035,1278 +5033,6 @@ prepare_tagpreview(
 
 #endif
 
-
-/*
- * ":help": open a read-only window on a help file
- */
-    void
-ex_help(exarg_T *eap)
-{
-    char_u	*arg;
-    char_u	*tag;
-    FILE	*helpfd;	// file descriptor of help file
-    int		n;
-    int		i;
-    win_T	*wp;
-    int		num_matches;
-    char_u	**matches;
-    char_u	*p;
-    int		empty_fnum = 0;
-    int		alt_fnum = 0;
-    buf_T	*buf;
-#ifdef FEAT_MULTI_LANG
-    int		len;
-    char_u	*lang;
-#endif
-#ifdef FEAT_FOLDING
-    int		old_KeyTyped = KeyTyped;
-#endif
-
-    if (eap != NULL)
-    {
-	/*
-	 * A ":help" command ends at the first LF, or at a '|' that is
-	 * followed by some text.  Set nextcmd to the following command.
-	 */
-	for (arg = eap->arg; *arg; ++arg)
-	{
-	    if (*arg == '\n' || *arg == '\r'
-		    || (*arg == '|' && arg[1] != NUL && arg[1] != '|'))
-	    {
-		*arg++ = NUL;
-		eap->nextcmd = arg;
-		break;
-	    }
-	}
-	arg = eap->arg;
-
-	if (eap->forceit && *arg == NUL && !curbuf->b_help)
-	{
-	    emsg(_("E478: Don't panic!"));
-	    return;
-	}
-
-	if (eap->skip)	    // not executing commands
-	    return;
-    }
-    else
-	arg = (char_u *)"";
-
-    // remove trailing blanks
-    p = arg + STRLEN(arg) - 1;
-    while (p > arg && VIM_ISWHITE(*p) && p[-1] != '\\')
-	*p-- = NUL;
-
-#ifdef FEAT_MULTI_LANG
-    // Check for a specified language
-    lang = check_help_lang(arg);
-#endif
-
-    // When no argument given go to the index.
-    if (*arg == NUL)
-	arg = (char_u *)"help.txt";
-
-    /*
-     * Check if there is a match for the argument.
-     */
-    n = find_help_tags(arg, &num_matches, &matches,
-						 eap != NULL && eap->forceit);
-
-    i = 0;
-#ifdef FEAT_MULTI_LANG
-    if (n != FAIL && lang != NULL)
-	// Find first item with the requested language.
-	for (i = 0; i < num_matches; ++i)
-	{
-	    len = (int)STRLEN(matches[i]);
-	    if (len > 3 && matches[i][len - 3] == '@'
-				  && STRICMP(matches[i] + len - 2, lang) == 0)
-		break;
-	}
-#endif
-    if (i >= num_matches || n == FAIL)
-    {
-#ifdef FEAT_MULTI_LANG
-	if (lang != NULL)
-	    semsg(_("E661: Sorry, no '%s' help for %s"), lang, arg);
-	else
-#endif
-	    semsg(_("E149: Sorry, no help for %s"), arg);
-	if (n != FAIL)
-	    FreeWild(num_matches, matches);
-	return;
-    }
-
-    // The first match (in the requested language) is the best match.
-    tag = vim_strsave(matches[i]);
-    FreeWild(num_matches, matches);
-
-#ifdef FEAT_GUI
-    need_mouse_correct = TRUE;
-#endif
-
-    /*
-     * Re-use an existing help window or open a new one.
-     * Always open a new one for ":tab help".
-     */
-    if (!bt_help(curwin->w_buffer) || cmdmod.tab != 0)
-    {
-	if (cmdmod.tab != 0)
-	    wp = NULL;
-	else
-	    FOR_ALL_WINDOWS(wp)
-		if (bt_help(wp->w_buffer))
-		    break;
-	if (wp != NULL && wp->w_buffer->b_nwindows > 0)
-	    win_enter(wp, TRUE);
-	else
-	{
-	    /*
-	     * There is no help window yet.
-	     * Try to open the file specified by the "helpfile" option.
-	     */
-	    if ((helpfd = mch_fopen((char *)p_hf, READBIN)) == NULL)
-	    {
-		smsg(_("Sorry, help file \"%s\" not found"), p_hf);
-		goto erret;
-	    }
-	    fclose(helpfd);
-
-	    // Split off help window; put it at far top if no position
-	    // specified, the current window is vertically split and
-	    // narrow.
-	    n = WSP_HELP;
-	    if (cmdmod.split == 0 && curwin->w_width != Columns
-						  && curwin->w_width < 80)
-		n |= WSP_TOP;
-	    if (win_split(0, n) == FAIL)
-		goto erret;
-
-	    if (curwin->w_height < p_hh)
-		win_setheight((int)p_hh);
-
-	    /*
-	     * Open help file (do_ecmd() will set b_help flag, readfile() will
-	     * set b_p_ro flag).
-	     * Set the alternate file to the previously edited file.
-	     */
-	    alt_fnum = curbuf->b_fnum;
-	    (void)do_ecmd(0, NULL, NULL, NULL, ECMD_LASTL,
-			  ECMD_HIDE + ECMD_SET_HELP,
-			  NULL);  // buffer is still open, don't store info
-	    if (!cmdmod.keepalt)
-		curwin->w_alt_fnum = alt_fnum;
-	    empty_fnum = curbuf->b_fnum;
-	}
-    }
-
-    if (!p_im)
-	restart_edit = 0;	    // don't want insert mode in help file
-
-#ifdef FEAT_FOLDING
-    // Restore KeyTyped, setting 'filetype=help' may reset it.
-    // It is needed for do_tag top open folds under the cursor.
-    KeyTyped = old_KeyTyped;
-#endif
-
-    if (tag != NULL)
-	do_tag(tag, DT_HELP, 1, FALSE, TRUE);
-
-    // Delete the empty buffer if we're not using it.  Careful: autocommands
-    // may have jumped to another window, check that the buffer is not in a
-    // window.
-    if (empty_fnum != 0 && curbuf->b_fnum != empty_fnum)
-    {
-	buf = buflist_findnr(empty_fnum);
-	if (buf != NULL && buf->b_nwindows == 0)
-	    wipe_buffer(buf, TRUE);
-    }
-
-    // keep the previous alternate file
-    if (alt_fnum != 0 && curwin->w_alt_fnum == empty_fnum && !cmdmod.keepalt)
-	curwin->w_alt_fnum = alt_fnum;
-
-erret:
-    vim_free(tag);
-}
-
-/*
- * ":helpclose": Close one help window
- */
-    void
-ex_helpclose(exarg_T *eap UNUSED)
-{
-    win_T *win;
-
-    FOR_ALL_WINDOWS(win)
-    {
-	if (bt_help(win->w_buffer))
-	{
-	    win_close(win, FALSE);
-	    return;
-	}
-    }
-}
-
-#if defined(FEAT_MULTI_LANG) || defined(PROTO)
-/*
- * In an argument search for a language specifiers in the form "@xx".
- * Changes the "@" to NUL if found, and returns a pointer to "xx".
- * Returns NULL if not found.
- */
-    char_u *
-check_help_lang(char_u *arg)
-{
-    int len = (int)STRLEN(arg);
-
-    if (len >= 3 && arg[len - 3] == '@' && ASCII_ISALPHA(arg[len - 2])
-					       && ASCII_ISALPHA(arg[len - 1]))
-    {
-	arg[len - 3] = NUL;		// remove the '@'
-	return arg + len - 2;
-    }
-    return NULL;
-}
-#endif
-
-/*
- * Return a heuristic indicating how well the given string matches.  The
- * smaller the number, the better the match.  This is the order of priorities,
- * from best match to worst match:
- *	- Match with least alphanumeric characters is better.
- *	- Match with least total characters is better.
- *	- Match towards the start is better.
- *	- Match starting with "+" is worse (feature instead of command)
- * Assumption is made that the matched_string passed has already been found to
- * match some string for which help is requested.  webb.
- */
-    int
-help_heuristic(
-    char_u	*matched_string,
-    int		offset,			// offset for match
-    int		wrong_case)		// no matching case
-{
-    int		num_letters;
-    char_u	*p;
-
-    num_letters = 0;
-    for (p = matched_string; *p; p++)
-	if (ASCII_ISALNUM(*p))
-	    num_letters++;
-
-    /*
-     * Multiply the number of letters by 100 to give it a much bigger
-     * weighting than the number of characters.
-     * If there only is a match while ignoring case, add 5000.
-     * If the match starts in the middle of a word, add 10000 to put it
-     * somewhere in the last half.
-     * If the match is more than 2 chars from the start, multiply by 200 to
-     * put it after matches at the start.
-     */
-    if (ASCII_ISALNUM(matched_string[offset]) && offset > 0
-				 && ASCII_ISALNUM(matched_string[offset - 1]))
-	offset += 10000;
-    else if (offset > 2)
-	offset *= 200;
-    if (wrong_case)
-	offset += 5000;
-    // Features are less interesting than the subjects themselves, but "+"
-    // alone is not a feature.
-    if (matched_string[0] == '+' && matched_string[1] != NUL)
-	offset += 100;
-    return (int)(100 * num_letters + STRLEN(matched_string) + offset);
-}
-
-/*
- * Compare functions for qsort() below, that checks the help heuristics number
- * that has been put after the tagname by find_tags().
- */
-    static int
-help_compare(const void *s1, const void *s2)
-{
-    char    *p1;
-    char    *p2;
-    int	    cmp;
-
-    p1 = *(char **)s1 + strlen(*(char **)s1) + 1;
-    p2 = *(char **)s2 + strlen(*(char **)s2) + 1;
-
-    // Compare by help heuristic number first.
-    cmp = strcmp(p1, p2);
-    if (cmp != 0)
-	return cmp;
-
-    // Compare by strings as tie-breaker when same heuristic number.
-    return strcmp(*(char **)s1, *(char **)s2);
-}
-
-/*
- * Find all help tags matching "arg", sort them and return in matches[], with
- * the number of matches in num_matches.
- * The matches will be sorted with a "best" match algorithm.
- * When "keep_lang" is TRUE try keeping the language of the current buffer.
- */
-    int
-find_help_tags(
-    char_u	*arg,
-    int		*num_matches,
-    char_u	***matches,
-    int		keep_lang)
-{
-    char_u	*s, *d;
-    int		i;
-    static char *(mtable[]) = {"*", "g*", "[*", "]*", ":*",
-			       "/*", "/\\*", "\"*", "**",
-			       "cpo-*", "/\\(\\)", "/\\%(\\)",
-			       "?", ":?", "?<CR>", "g?", "g?g?", "g??",
-			       "-?", "q?", "v_g?",
-			       "/\\?", "/\\z(\\)", "\\=", ":s\\=",
-			       "[count]", "[quotex]",
-			       "[range]", ":[range]",
-			       "[pattern]", "\\|", "\\%$",
-			       "s/\\~", "s/\\U", "s/\\L",
-			       "s/\\1", "s/\\2", "s/\\3", "s/\\9"};
-    static char *(rtable[]) = {"star", "gstar", "[star", "]star", ":star",
-			       "/star", "/\\\\star", "quotestar", "starstar",
-			       "cpo-star", "/\\\\(\\\\)", "/\\\\%(\\\\)",
-			       "?", ":?", "?<CR>", "g?", "g?g?", "g??",
-			       "-?", "q?", "v_g?",
-			       "/\\\\?", "/\\\\z(\\\\)", "\\\\=", ":s\\\\=",
-			       "\\[count]", "\\[quotex]",
-			       "\\[range]", ":\\[range]",
-			       "\\[pattern]", "\\\\bar", "/\\\\%\\$",
-			       "s/\\\\\\~", "s/\\\\U", "s/\\\\L",
-			       "s/\\\\1", "s/\\\\2", "s/\\\\3", "s/\\\\9"};
-    static char *(expr_table[]) = {"!=?", "!~?", "<=?", "<?", "==?", "=~?",
-				">=?", ">?", "is?", "isnot?"};
-    int flags;
-
-    d = IObuff;		    // assume IObuff is long enough!
-
-    if (STRNICMP(arg, "expr-", 5) == 0)
-    {
-	// When the string starting with "expr-" and containing '?' and matches
-	// the table, it is taken literally (but ~ is escaped).  Otherwise '?'
-	// is recognized as a wildcard.
-	for (i = (int)(sizeof(expr_table) / sizeof(char *)); --i >= 0; )
-	    if (STRCMP(arg + 5, expr_table[i]) == 0)
-	    {
-		int si = 0, di = 0;
-
-		for (;;)
-		{
-		    if (arg[si] == '~')
-			d[di++] = '\\';
-		    d[di++] = arg[si];
-		    if (arg[si] == NUL)
-			break;
-		    ++si;
-		}
-		break;
-	    }
-    }
-    else
-    {
-	// Recognize a few exceptions to the rule.  Some strings that contain
-	// '*' with "star".  Otherwise '*' is recognized as a wildcard.
-	for (i = (int)(sizeof(mtable) / sizeof(char *)); --i >= 0; )
-	    if (STRCMP(arg, mtable[i]) == 0)
-	    {
-		STRCPY(d, rtable[i]);
-		break;
-	    }
-    }
-
-    if (i < 0)	// no match in table
-    {
-	// Replace "\S" with "/\\S", etc.  Otherwise every tag is matched.
-	// Also replace "\%^" and "\%(", they match every tag too.
-	// Also "\zs", "\z1", etc.
-	// Also "\@<", "\@=", "\@<=", etc.
-	// And also "\_$" and "\_^".
-	if (arg[0] == '\\'
-		&& ((arg[1] != NUL && arg[2] == NUL)
-		    || (vim_strchr((char_u *)"%_z@", arg[1]) != NULL
-							   && arg[2] != NUL)))
-	{
-	    STRCPY(d, "/\\\\");
-	    STRCPY(d + 3, arg + 1);
-	    // Check for "/\\_$", should be "/\\_\$"
-	    if (d[3] == '_' && d[4] == '$')
-		STRCPY(d + 4, "\\$");
-	}
-	else
-	{
-	  // Replace:
-	  // "[:...:]" with "\[:...:]"
-	  // "[++...]" with "\[++...]"
-	  // "\{" with "\\{"		   -- matching "} \}"
-	    if ((arg[0] == '[' && (arg[1] == ':'
-			 || (arg[1] == '+' && arg[2] == '+')))
-		    || (arg[0] == '\\' && arg[1] == '{'))
-	      *d++ = '\\';
-
-	  /*
-	   * If tag starts with "('", skip the "(". Fixes CTRL-] on ('option'.
-	   */
-	  if (*arg == '(' && arg[1] == '\'')
-	      arg++;
-	  for (s = arg; *s; ++s)
-	  {
-	    /*
-	     * Replace "|" with "bar" and '"' with "quote" to match the name of
-	     * the tags for these commands.
-	     * Replace "*" with ".*" and "?" with "." to match command line
-	     * completion.
-	     * Insert a backslash before '~', '$' and '.' to avoid their
-	     * special meaning.
-	     */
-	    if (d - IObuff > IOSIZE - 10)	// getting too long!?
-		break;
-	    switch (*s)
-	    {
-		case '|':   STRCPY(d, "bar");
-			    d += 3;
-			    continue;
-		case '"':   STRCPY(d, "quote");
-			    d += 5;
-			    continue;
-		case '*':   *d++ = '.';
-			    break;
-		case '?':   *d++ = '.';
-			    continue;
-		case '$':
-		case '.':
-		case '~':   *d++ = '\\';
-			    break;
-	    }
-
-	    /*
-	     * Replace "^x" by "CTRL-X". Don't do this for "^_" to make
-	     * ":help i_^_CTRL-D" work.
-	     * Insert '-' before and after "CTRL-X" when applicable.
-	     */
-	    if (*s < ' ' || (*s == '^' && s[1] && (ASCII_ISALPHA(s[1])
-			   || vim_strchr((char_u *)"?@[\\]^", s[1]) != NULL)))
-	    {
-		if (d > IObuff && d[-1] != '_' && d[-1] != '\\')
-		    *d++ = '_';		// prepend a '_' to make x_CTRL-x
-		STRCPY(d, "CTRL-");
-		d += 5;
-		if (*s < ' ')
-		{
-#ifdef EBCDIC
-		    *d++ = CtrlChar(*s);
-#else
-		    *d++ = *s + '@';
-#endif
-		    if (d[-1] == '\\')
-			*d++ = '\\';	// double a backslash
-		}
-		else
-		    *d++ = *++s;
-		if (s[1] != NUL && s[1] != '_')
-		    *d++ = '_';		// append a '_'
-		continue;
-	    }
-	    else if (*s == '^')		// "^" or "CTRL-^" or "^_"
-		*d++ = '\\';
-
-	    /*
-	     * Insert a backslash before a backslash after a slash, for search
-	     * pattern tags: "/\|" --> "/\\|".
-	     */
-	    else if (s[0] == '\\' && s[1] != '\\'
-					       && *arg == '/' && s == arg + 1)
-		*d++ = '\\';
-
-	    // "CTRL-\_" -> "CTRL-\\_" to avoid the special meaning of "\_" in
-	    // "CTRL-\_CTRL-N"
-	    if (STRNICMP(s, "CTRL-\\_", 7) == 0)
-	    {
-		STRCPY(d, "CTRL-\\\\");
-		d += 7;
-		s += 6;
-	    }
-
-	    *d++ = *s;
-
-	    /*
-	     * If tag contains "({" or "([", tag terminates at the "(".
-	     * This is for help on functions, e.g.: abs({expr}).
-	     */
-	    if (*s == '(' && (s[1] == '{' || s[1] =='['))
-		break;
-
-	    /*
-	     * If tag starts with ', toss everything after a second '. Fixes
-	     * CTRL-] on 'option'. (would include the trailing '.').
-	     */
-	    if (*s == '\'' && s > arg && *arg == '\'')
-		break;
-	    // Also '{' and '}'.
-	    if (*s == '}' && s > arg && *arg == '{')
-		break;
-	  }
-	  *d = NUL;
-
-	  if (*IObuff == '`')
-	  {
-	      if (d > IObuff + 2 && d[-1] == '`')
-	      {
-		  // remove the backticks from `command`
-		  mch_memmove(IObuff, IObuff + 1, STRLEN(IObuff));
-		  d[-2] = NUL;
-	      }
-	      else if (d > IObuff + 3 && d[-2] == '`' && d[-1] == ',')
-	      {
-		  // remove the backticks and comma from `command`,
-		  mch_memmove(IObuff, IObuff + 1, STRLEN(IObuff));
-		  d[-3] = NUL;
-	      }
-	      else if (d > IObuff + 4 && d[-3] == '`'
-					     && d[-2] == '\\' && d[-1] == '.')
-	      {
-		  // remove the backticks and dot from `command`\.
-		  mch_memmove(IObuff, IObuff + 1, STRLEN(IObuff));
-		  d[-4] = NUL;
-	      }
-	  }
-	}
-    }
-
-    *matches = (char_u **)"";
-    *num_matches = 0;
-    flags = TAG_HELP | TAG_REGEXP | TAG_NAMES | TAG_VERBOSE | TAG_NO_TAGFUNC;
-    if (keep_lang)
-	flags |= TAG_KEEP_LANG;
-    if (find_tags(IObuff, num_matches, matches, flags, (int)MAXCOL, NULL) == OK
-	    && *num_matches > 0)
-    {
-	// Sort the matches found on the heuristic number that is after the
-	// tag name.
-	qsort((void *)*matches, (size_t)*num_matches,
-					      sizeof(char_u *), help_compare);
-	// Delete more than TAG_MANY to reduce the size of the listing.
-	while (*num_matches > TAG_MANY)
-	    vim_free((*matches)[--*num_matches]);
-    }
-    return OK;
-}
-
-/*
- * Called when starting to edit a buffer for a help file.
- */
-    static void
-prepare_help_buffer(void)
-{
-    char_u	*p;
-
-    curbuf->b_help = TRUE;
-#ifdef FEAT_QUICKFIX
-    set_string_option_direct((char_u *)"buftype", -1,
-				     (char_u *)"help", OPT_FREE|OPT_LOCAL, 0);
-#endif
-
-    /*
-     * Always set these options after jumping to a help tag, because the
-     * user may have an autocommand that gets in the way.
-     * Accept all ASCII chars for keywords, except ' ', '*', '"', '|', and
-     * latin1 word characters (for translated help files).
-     * Only set it when needed, buf_init_chartab() is some work.
-     */
-    p =
-#ifdef EBCDIC
-	    (char_u *)"65-255,^*,^|,^\"";
-#else
-	    (char_u *)"!-~,^*,^|,^\",192-255";
-#endif
-    if (STRCMP(curbuf->b_p_isk, p) != 0)
-    {
-	set_string_option_direct((char_u *)"isk", -1, p, OPT_FREE|OPT_LOCAL, 0);
-	check_buf_options(curbuf);
-	(void)buf_init_chartab(curbuf, FALSE);
-    }
-
-#ifdef FEAT_FOLDING
-    // Don't use the global foldmethod.
-    set_string_option_direct((char_u *)"fdm", -1, (char_u *)"manual",
-						       OPT_FREE|OPT_LOCAL, 0);
-#endif
-
-    curbuf->b_p_ts = 8;		// 'tabstop' is 8
-    curwin->w_p_list = FALSE;	// no list mode
-
-    curbuf->b_p_ma = FALSE;	// not modifiable
-    curbuf->b_p_bin = FALSE;	// reset 'bin' before reading file
-    curwin->w_p_nu = 0;		// no line numbers
-    curwin->w_p_rnu = 0;	// no relative line numbers
-    RESET_BINDING(curwin);	// no scroll or cursor binding
-#ifdef FEAT_ARABIC
-    curwin->w_p_arab = FALSE;	// no arabic mode
-#endif
-#ifdef FEAT_RIGHTLEFT
-    curwin->w_p_rl  = FALSE;	// help window is left-to-right
-#endif
-#ifdef FEAT_FOLDING
-    curwin->w_p_fen = FALSE;	// No folding in the help window
-#endif
-#ifdef FEAT_DIFF
-    curwin->w_p_diff = FALSE;	// No 'diff'
-#endif
-#ifdef FEAT_SPELL
-    curwin->w_p_spell = FALSE;	// No spell checking
-#endif
-
-    set_buflisted(FALSE);
-}
-
-/*
- * After reading a help file: May cleanup a help buffer when syntax
- * highlighting is not used.
- */
-    void
-fix_help_buffer(void)
-{
-    linenr_T	lnum;
-    char_u	*line;
-    int		in_example = FALSE;
-    int		len;
-    char_u	*fname;
-    char_u	*p;
-    char_u	*rt;
-    int		mustfree;
-
-    // Set filetype to "help" if still needed.
-    if (STRCMP(curbuf->b_p_ft, "help") != 0)
-    {
-	++curbuf_lock;
-	set_option_value((char_u *)"ft", 0L, (char_u *)"help", OPT_LOCAL);
-	--curbuf_lock;
-    }
-
-#ifdef FEAT_SYN_HL
-    if (!syntax_present(curwin))
-#endif
-    {
-	for (lnum = 1; lnum <= curbuf->b_ml.ml_line_count; ++lnum)
-	{
-	    line = ml_get_buf(curbuf, lnum, FALSE);
-	    len = (int)STRLEN(line);
-	    if (in_example && len > 0 && !VIM_ISWHITE(line[0]))
-	    {
-		// End of example: non-white or '<' in first column.
-		if (line[0] == '<')
-		{
-		    // blank-out a '<' in the first column
-		    line = ml_get_buf(curbuf, lnum, TRUE);
-		    line[0] = ' ';
-		}
-		in_example = FALSE;
-	    }
-	    if (!in_example && len > 0)
-	    {
-		if (line[len - 1] == '>' && (len == 1 || line[len - 2] == ' '))
-		{
-		    // blank-out a '>' in the last column (start of example)
-		    line = ml_get_buf(curbuf, lnum, TRUE);
-		    line[len - 1] = ' ';
-		    in_example = TRUE;
-		}
-		else if (line[len - 1] == '~')
-		{
-		    // blank-out a '~' at the end of line (header marker)
-		    line = ml_get_buf(curbuf, lnum, TRUE);
-		    line[len - 1] = ' ';
-		}
-	    }
-	}
-    }
-
-    /*
-     * In the "help.txt" and "help.abx" file, add the locally added help
-     * files.  This uses the very first line in the help file.
-     */
-    fname = gettail(curbuf->b_fname);
-    if (fnamecmp(fname, "help.txt") == 0
-#ifdef FEAT_MULTI_LANG
-	|| (fnamencmp(fname, "help.", 5) == 0
-	    && ASCII_ISALPHA(fname[5])
-	    && ASCII_ISALPHA(fname[6])
-	    && TOLOWER_ASC(fname[7]) == 'x'
-	    && fname[8] == NUL)
-#endif
-	)
-    {
-	for (lnum = 1; lnum < curbuf->b_ml.ml_line_count; ++lnum)
-	{
-	    line = ml_get_buf(curbuf, lnum, FALSE);
-	    if (strstr((char *)line, "*local-additions*") == NULL)
-		continue;
-
-	    // Go through all directories in 'runtimepath', skipping
-	    // $VIMRUNTIME.
-	    p = p_rtp;
-	    while (*p != NUL)
-	    {
-		copy_option_part(&p, NameBuff, MAXPATHL, ",");
-		mustfree = FALSE;
-		rt = vim_getenv((char_u *)"VIMRUNTIME", &mustfree);
-		if (rt != NULL &&
-			    fullpathcmp(rt, NameBuff, FALSE, TRUE) != FPC_SAME)
-		{
-		    int		fcount;
-		    char_u	**fnames;
-		    FILE	*fd;
-		    char_u	*s;
-		    int		fi;
-		    vimconv_T	vc;
-		    char_u	*cp;
-
-		    // Find all "doc/ *.txt" files in this directory.
-		    add_pathsep(NameBuff);
-#ifdef FEAT_MULTI_LANG