/*	$OpenBSD: emacs.c,v 1.38 2005/08/01 04:27:31 deraadt Exp $	*/

/*
 *  Emacs-like command line editing and history
 *
 *  created by Ron Natalie at BRL
 *  modified by Doug Kingston, Doug Gwyn, and Lou Salkind
 *  adapted to PD ksh by Eric Gisin
 */

#include "config.h"
#ifdef EMACS

#include "sh.h"
#include <sys/stat.h>
#include <ctype.h>
#include <locale.h>
#include "edit.h"

static	Area	aedit;
#define	AEDIT	&aedit		/* area for kill ring and macro defns */

#define	CTRL(x)		((x) == '?' ? 0x7F : (x) & 0x1F)	/* ASCII */
#define	UNCTRL(x)	((x) == 0x7F ? '?' : (x) | 0x40)	/* ASCII */
#define	META(x)		((x) & 0x7f)
#define	ISMETA(x)	(Flag(FEMACSUSEMETA) && ((x) & 0x80))


/* values returned by keyboard functions */
#define	KSTD	0
#define	KEOL	1		/* ^M, ^J */
#define	KINTR	2		/* ^G, ^C */

struct	x_ftab {
	int		(*xf_func)(int c);
	const char	*xf_name;
	short		xf_flags;
};

struct x_defbindings {
	u_char		xdb_func;	/* XFUNC_* */
	unsigned char	xdb_tab;
	unsigned char	xdb_char;
};

#define XF_ARG		1	/* command takes number prefix */
#define	XF_NOBIND	2	/* not allowed to bind to function */
#define	XF_PREFIX	4	/* function sets prefix */

/* Separator for completion */
#define	is_cfs(c)	(c == ' ' || c == '\t' || c == '"' || c == '\'')
#define	is_mfs(c)	(!(isalnum(c) || c == '_' || c == '$'))  /* Separator for motion */

# define CHARMASK	0xFF		/* 8-bit character mask */
# define X_NTABS	3		/* normal, meta1, meta2 */
#define X_TABSZ		(CHARMASK+1)	/* size of keydef tables etc */

/* Arguments for do_complete()
 * 0 = enumerate  M-= complete as much as possible and then list
 * 1 = complete   M-Esc
 * 2 = list       M-?
 */
typedef enum {
	CT_LIST,	/* list the possible completions */
	CT_COMPLETE,	/* complete to longest prefix */
	CT_COMPLIST	/* complete and then list (if non-exact) */
} Comp_type;

/* { from 4.9 edit.h */
/*
 * The following are used for my horizontal scrolling stuff
 */
static char   *xbuf;		/* beg input buffer */
static char   *xend;		/* end input buffer */
static char    *xcp;		/* current position */
static char    *xep;		/* current end */
static char    *xbp;		/* start of visible portion of input buffer */
static char    *xlp;		/* last char visible on screen */
static int	x_adj_ok;
/*
 * we use x_adj_done so that functions can tell
 * whether x_adjust() has been called while they are active.
 */
static int	x_adj_done;

static int	xx_cols;
static int	x_col;
static int	x_displen;
static int	x_arg;		/* general purpose arg */
static int	x_arg_defaulted;/* x_arg not explicitly set; defaulted to 1 */

static int	xlp_valid;
/* end from 4.9 edit.h } */

static	int	x_prefix1 = CTRL('['), x_prefix2 = CTRL('X');
static	char   **x_histp;	/* history position */
static	int	x_nextcmd;	/* for newline-and-next */
static	char	*xmp;		/* mark pointer */
static	u_char	x_last_command;
static	u_char	(*x_tab)[X_TABSZ];	/* key definition */
static	char    *(*x_atab)[X_TABSZ];	/* macro definitions */
static	unsigned char	x_bound[(X_TABSZ * X_NTABS + 7) / 8];
#define	KILLSIZE	20
static	char    *killstack[KILLSIZE];
static	int	killsp, killtp;
static	int	x_curprefix;
static	char    *macroptr;
static	int	prompt_skip;

static int      x_ins(char *);
static void     x_delete(int, int);
static int	x_bword(void);
static int	x_fword(void);
static void     x_goto(char *);
static void     x_bs(int);
static int      x_size_str(char *);
static int      x_size(int);
static void     x_zots(char *);
static void     x_zotc(int);
static void     x_load_hist(char **);
static int      x_search(char *, int, int);
static int      x_match(char *, char *);
static void	x_redraw(int);
static void     x_push(int);
static char *   x_mapin(const char *);
static char *   x_mapout(int);
static void     x_print(int, int);
static void	x_adjust(void);
static void	x_e_ungetc(int);
static int	x_e_getc(void);
static void	x_e_putc(int);
static void	x_e_puts(const char *);
static int	x_comment(int);
static int	x_fold_case(int);
static char	*x_lastcp(void);
static void	do_complete(int, Comp_type);
static int	x_emacs_putbuf(const char *, size_t);


/* The lines between START-FUNC-TAB .. END-FUNC-TAB are run through a
 * script (emacs-gen.sh) that generates emacs.out which contains:
 *	- function declarations for x_* functions
 *	- defines of the form XFUNC_<name> where <name> is function
 *	  name, sans leading x_.
 * Note that the script treats #ifdef and { 0, 0, 0} specially - use with
 * caution.
 */
#include "emacs.out"
static const struct x_ftab x_ftab[] = {
/* @START-FUNC-TAB@ */
	{ x_abort,		"abort",			0 },
	{ x_beg_hist,		"beginning-of-history",		0 },
	{ x_comp_comm,		"complete-command",		0 },
	{ x_comp_file,		"complete-file",		0 },
	{ x_complete,		"complete",			0 },
	{ x_del_back,		"delete-char-backward",		XF_ARG },
	{ x_del_bword,		"delete-word-backward",		XF_ARG },
	{ x_del_char,		"delete-char-forward",		XF_ARG },
	{ x_del_fword,		"delete-word-forward",		XF_ARG },
	{ x_del_line,		"kill-line",			0 },
	{ x_draw_line,		"redraw",			0 },
	{ x_end_hist,		"end-of-history",		0 },
	{ x_end_of_text,	"eot",				0 },
	{ x_enumerate,		"list",				0 },
	{ x_eot_del,		"eot-or-delete",		XF_ARG },
	{ x_error,		"error",			0 },
	{ x_goto_hist,		"goto-history",			XF_ARG },
	{ x_ins_string,		"macro-string",			XF_NOBIND },
	{ x_insert,		"auto-insert",			XF_ARG },
	{ x_kill,		"kill-to-eol",			XF_ARG },
	{ x_kill_region,	"kill-region",			0 },
	{ x_list_comm,		"list-command",			0 },
	{ x_list_file,		"list-file",			0 },
	{ x_literal,		"quote",			0 },
	{ x_meta1,		"prefix-1",			XF_PREFIX },
	{ x_meta2,		"prefix-2",			XF_PREFIX },
	{ x_meta_yank,		"yank-pop",			0 },
	{ x_mv_back,		"backward-char",		XF_ARG },
	{ x_mv_begin,		"beginning-of-line",		0 },
	{ x_mv_bword,		"backward-word",		XF_ARG },
	{ x_mv_end,		"end-of-line",			0 },
	{ x_mv_forw,		"forward-char",			XF_ARG },
	{ x_mv_fword,		"forward-word",			XF_ARG },
	{ x_newline,		"newline",			0 },
	{ x_next_com,		"down-history",			XF_ARG },
	{ x_nl_next_com,	"newline-and-next",		0 },
	{ x_noop,		"no-op",			0 },
	{ x_prev_com,		"up-history",			XF_ARG },
	{ x_prev_histword,	"prev-hist-word",		XF_ARG },
	{ x_search_char_forw,	"search-character-forward",	XF_ARG },
	{ x_search_char_back,	"search-character-backward",	XF_ARG },
	{ x_search_hist,	"search-history",		0 },
	{ x_set_mark,		"set-mark-command",		0 },
	{ x_stuff,		"stuff",			0 },
	{ x_stuffreset,		"stuff-reset",			0 },
	{ x_transpose,		"transpose-chars",		0 },
	{ x_version,		"version",			0 },
	{ x_xchg_point_mark,	"exchange-point-and-mark",	0 },
	{ x_yank,		"yank",				0 },
	{ x_comp_list,		"complete-list",		0 },
	{ x_expand,		"expand-file",			0 },
	{ x_fold_capitalize,	"capitalize-word",		XF_ARG },
	{ x_fold_lower,		"downcase-word",		XF_ARG },
	{ x_fold_upper,		"upcase-word",			XF_ARG },
	{ x_set_arg,		"set-arg",			XF_NOBIND },
	{ x_comment,		"comment",			0 },
#ifdef SILLY
	{ x_game_of_life,	"play-game-of-life",		0 },
#else
	{ 0, 0, 0 },
#endif
#ifdef DEBUG
	{ x_debug_info,		"debug-info",			0 },
#else
	{ 0, 0, 0 },
#endif
	{ 0, 0, 0 },
/* @END-FUNC-TAB@ */
};

static	struct x_defbindings const x_defbindings[] = {
	{ XFUNC_del_back,		0, CTRL('?') },
	{ XFUNC_del_bword,		1, CTRL('?') },
	{ XFUNC_eot_del,		0, CTRL('D') },
	{ XFUNC_del_back,		0, CTRL('H') },
	{ XFUNC_del_bword,		1, CTRL('H') },
	{ XFUNC_del_bword,		1,      'h'  },
	{ XFUNC_mv_bword,		1,      'b'  },
	{ XFUNC_mv_fword,		1,      'f'  },
	{ XFUNC_del_fword,		1,      'd'  },
	{ XFUNC_mv_back,		0, CTRL('B') },
	{ XFUNC_mv_forw,		0, CTRL('F') },
	{ XFUNC_search_char_forw,	0, CTRL(']') },
	{ XFUNC_search_char_back,	1, CTRL(']') },
	{ XFUNC_newline,		0, CTRL('M') },
	{ XFUNC_newline,		0, CTRL('J') },
	{ XFUNC_end_of_text,		0, CTRL('_') },
	{ XFUNC_abort,			0, CTRL('G') },
	{ XFUNC_prev_com,		0, CTRL('P') },
	{ XFUNC_next_com,		0, CTRL('N') },
	{ XFUNC_nl_next_com,		0, CTRL('O') },
	{ XFUNC_search_hist,		0, CTRL('R') },
	{ XFUNC_beg_hist,		1,      '<'  },
	{ XFUNC_end_hist,		1,      '>'  },
	{ XFUNC_goto_hist,		1,      'g'  },
	{ XFUNC_mv_end,			0, CTRL('E') },
	{ XFUNC_mv_begin,		0, CTRL('A') },
	{ XFUNC_draw_line,		0, CTRL('L') },
	{ XFUNC_meta1,			0, CTRL('[') },
	{ XFUNC_meta2,			0, CTRL('X') },
	{ XFUNC_kill,			0, CTRL('K') },
	{ XFUNC_yank,			0, CTRL('Y') },
	{ XFUNC_meta_yank,		1,      'y'  },
	{ XFUNC_literal,		0, CTRL('^') },
	{ XFUNC_comment,		1,	'#'  },
#if defined(TIOCSTI)
	{ XFUNC_stuff,			0, CTRL('T') },
#else
	{ XFUNC_transpose,		0, CTRL('T') },
#endif
	{ XFUNC_complete,		1, CTRL('[') },
	{ XFUNC_comp_list,		0, CTRL('I') },
	{ XFUNC_comp_list,		1,	'='  },
	{ XFUNC_enumerate,		1,	'?'  },
	{ XFUNC_expand,			1,	'*'  },
	{ XFUNC_comp_file,		1, CTRL('X') },
	{ XFUNC_comp_comm,		2, CTRL('[') },
	{ XFUNC_list_comm,		2,	'?'  },
	{ XFUNC_list_file,		2, CTRL('Y') },
	{ XFUNC_set_mark,		1,	' '  },
	{ XFUNC_kill_region,		0, CTRL('W') },
	{ XFUNC_xchg_point_mark,	2, CTRL('X') },
	{ XFUNC_literal,		0, CTRL('V') },
#ifdef DEBUG
	{ XFUNC_debug_info,		1, CTRL('H') },
#endif
	{ XFUNC_prev_histword,		1,	'.'  },
	{ XFUNC_prev_histword,		1,	'_'  },
	{ XFUNC_set_arg,		1,	'0'  },
	{ XFUNC_set_arg,		1,	'1'  },
	{ XFUNC_set_arg,		1,	'2'  },
	{ XFUNC_set_arg,		1,	'3'  },
	{ XFUNC_set_arg,		1,	'4'  },
	{ XFUNC_set_arg,		1,	'5'  },
	{ XFUNC_set_arg,		1,	'6'  },
	{ XFUNC_set_arg,		1,	'7'  },
	{ XFUNC_set_arg,		1,	'8'  },
	{ XFUNC_set_arg,		1,	'9'  },
	{ XFUNC_fold_upper,		1,	'U'  },
	{ XFUNC_fold_upper,		1,	'u'  },
	{ XFUNC_fold_lower,		1,	'L'  },
	{ XFUNC_fold_lower,		1,	'l'  },
	{ XFUNC_fold_capitalize,	1,	'C'  },
	{ XFUNC_fold_capitalize,	1,	'c'  },
	/* These for ansi arrow keys: arguablely shouldn't be here by
	 * default, but its simpler/faster/smaller than using termcap
	 * entries.
	 */
	{ XFUNC_meta2,			1,	'['  },
	{ XFUNC_meta2,			1,	'O'  },
	{ XFUNC_prev_com,		2,	'A'  },
	{ XFUNC_next_com,		2,	'B'  },
	{ XFUNC_mv_forw,		2,	'C'  },
	{ XFUNC_mv_back,		2,	'D'  },
};

int
x_emacs(char *buf, size_t len)
{
	int	c;
	const char *p;
	int	i;
	u_char f;

	xbp = xbuf = buf; xend = buf + len;
	xlp = xcp = xep = buf;
	*xcp = 0;
	xlp_valid = true;
	xmp = NULL;
	x_curprefix = 0;
	macroptr = (char *) 0;
	x_histp = histptr + 1;
	x_last_command = XFUNC_error;

	xx_cols = x_cols;
	x_col = promptlen(prompt, &p);
	prompt_skip = p - prompt;
	x_adj_ok = 1;
	x_displen = xx_cols - 2 - x_col;
	x_adj_done = 0;

	pprompt(prompt, 0);

	if (x_nextcmd >= 0) {
		int off = source->line - x_nextcmd;
		if (histptr - history >= off)
			x_load_hist(histptr - off);
		x_nextcmd = -1;
	}

	while (1) {
		x_flush();
		if ((c = x_e_getc()) < 0)
			return 0;

		if (ISMETA(c)) {
			c = META(c);
			x_curprefix = 1;
		}

		f = x_curprefix == -1 ? XFUNC_insert :
		    x_tab[x_curprefix][c&CHARMASK];

		if (!(x_ftab[f].xf_flags & XF_PREFIX) &&
		    x_last_command != XFUNC_set_arg) {
			x_arg = 1;
			x_arg_defaulted = 1;
		}
		i = c | (x_curprefix << 8);
		x_curprefix = 0;
		switch (i = (*x_ftab[f].xf_func)(i)) {
		case KSTD:
			if (!(x_ftab[f].xf_flags & XF_PREFIX))
				x_last_command = f;
			break;
		case KEOL:
			i = xep - xbuf;
			return i;
		case KINTR:	/* special case for interrupt */
			trapsig(SIGINT);
			x_mode(false);
			unwind(LSHELL);
		}
	}
}

static int
x_insert(int c)
{
	char	str[2];

	/*
	 *  Should allow tab and control chars.
	 */
	if (c == 0) {
		x_e_putc(BEL);
		return KSTD;
	}
	str[0] = c;
	str[1] = '\0';
	while (x_arg--)
		x_ins(str);
	return KSTD;
}

static int
x_ins_string(int c)
{
	if (macroptr) {
		x_e_putc(BEL);
		return KSTD;
	}
	macroptr = x_atab[c>>8][c & CHARMASK];
	if (macroptr && !*macroptr) {
		/* XXX bell? */
		macroptr = (char *) 0;
	}
	return KSTD;
}

static int x_do_ins(const char *cp, int len);

static int
x_do_ins(const char *cp, int len)
{
	if (xep+len >= xend) {
		x_e_putc(BEL);
		return -1;
	}

	memmove(xcp+len, xcp, xep - xcp + 1);
	memmove(xcp, cp, len);
	xcp += len;
	xep += len;
	return 0;
}

static int
x_ins(char *s)
{
	char	*cp = xcp;
	int	adj = x_adj_done;

	if (x_do_ins(s, strlen(s)) < 0)
		return -1;
	/*
	 * x_zots() may result in a call to x_adjust()
	 * we want xcp to reflect the new position.
	 */
	xlp_valid = false;
	x_lastcp();
	x_adj_ok = (xcp >= xlp);
	x_zots(cp);
	if (adj == x_adj_done) {	/* has x_adjust() been called? */
		/* no */
		for (cp = xlp; cp > xcp; )
			x_bs(*--cp);
	}

	x_adj_ok = 1;
	return 0;
}

/*
 * this is used for x_escape() in do_complete()
 */
static int
x_emacs_putbuf(const char *s, size_t len)
{
	int rval;

	if ((rval = x_do_ins(s, len)) != 0)
		return (rval);
	return (rval);
}

static int
x_del_back(int c)
{
	int col = xcp - xbuf;

	if (col == 0) {
		x_e_putc(BEL);
		return KSTD;
	}
	if (x_arg > col)
		x_arg = col;
	x_goto(xcp - x_arg);
	x_delete(x_arg, false);
	return KSTD;
}

static int
x_del_char(int c)
{
	int nleft = xep - xcp;

	if (!nleft) {
		x_e_putc(BEL);
		return KSTD;
	}
	if (x_arg > nleft)
		x_arg = nleft;
	x_delete(x_arg, false);
	return KSTD;
}

/* Delete nc chars to the right of the cursor (including cursor position) */
static void
x_delete(int nc, int push)
{
	int	i,j;
	char	*cp;

	if (nc == 0)
		return;
	if (xmp != NULL && xmp > xcp) {
		if (xcp + nc > xmp)
			xmp = xcp;
		else
			xmp -= nc;
	}

	/*
	 * This lets us yank a word we have deleted.
	 */
	if (push)
		x_push(nc);

	xep -= nc;
	cp = xcp;
	j = 0;
	i = nc;
	while (i--) {
		j += x_size(*cp++);
	}
	memmove(xcp, xcp+nc, xep - xcp + 1);	/* Copies the null */
	x_adj_ok = 0;			/* don't redraw */
	x_zots(xcp);
	/*
	 * if we are already filling the line,
	 * there is no need to ' ','\b'.
	 * But if we must, make sure we do the minimum.
	 */
	if ((i = xx_cols - 2 - x_col) > 0) {
		j = (j < i) ? j : i;
		i = j;
		while (i--)
			x_e_putc(' ');
		i = j;
		while (i--)
			x_e_putc('\b');
	}
	/*x_goto(xcp);*/
	x_adj_ok = 1;
	xlp_valid = false;
	for (cp = x_lastcp(); cp > xcp; )
		x_bs(*--cp);

	return;
}

static int
x_del_bword(int c)
{
	x_delete(x_bword(), true);
	return KSTD;
}

static int
x_mv_bword(int c)
{
	(void)x_bword();
	return KSTD;
}

static int
x_mv_fword(int c)
{
	x_goto(xcp + x_fword());
	return KSTD;
}

static int
x_del_fword(int c)
{
	x_delete(x_fword(), true);
	return KSTD;
}

static int
x_bword(void)
{
	int	nc = 0;
	char	*cp = xcp;

	if (cp == xbuf) {
		x_e_putc(BEL);
		return 0;
	}
	while (x_arg--) {
		while (cp != xbuf && is_mfs(cp[-1])) {
			cp--;
			nc++;
		}
		while (cp != xbuf && !is_mfs(cp[-1])) {
			cp--;
			nc++;
		}
	}
	x_goto(cp);
	return nc;
}

static int
x_fword(void)
{
	int	nc = 0;
	char	*cp = xcp;

	if (cp == xep) {
		x_e_putc(BEL);
		return 0;
	}
	while (x_arg--) {
		while (cp != xep && is_mfs(*cp)) {
			cp++;
			nc++;
		}
		while (cp != xep && !is_mfs(*cp)) {
			cp++;
			nc++;
		}
	}
	return nc;
}

static void
x_goto(char *cp)
{
	if (cp < xbp || cp >= (xbp + x_displen)) {
		/* we are heading off screen */
		xcp = cp;
		x_adjust();
	} else if (cp < xcp) {		/* move back */
		while (cp < xcp)
			x_bs(*--xcp);
	} else if (cp > xcp) {		/* move forward */
		while (cp > xcp)
			x_zotc(*xcp++);
	}
}

static void
x_bs(int c)
{
	int i;

	i = x_size(c);
	while (i--)
		x_e_putc('\b');
}

static int
x_size_str(char *cp)
{
	int size = 0;
	while (*cp)
		size += x_size(*cp++);
	return size;
}

static int
x_size(int c)
{
	if (c=='\t')
		return 4;	/* Kludge, tabs are always four spaces. */
	if (iscntrl(c))		/* control char */
		return 2;
	return 1;
}

static void
x_zots(char *str)
{
	int	adj = x_adj_done;

	x_lastcp();
	while (*str && str < xlp && adj == x_adj_done)
		x_zotc(*str++);
}

static void
x_zotc(int c)
{
	if (c == '\t') {
		/*  Kludge, tabs are always four spaces.  */
		x_e_puts("    ");
	} else if (iscntrl(c)) {
		x_e_putc('^');
		x_e_putc(UNCTRL(c));
	} else
		x_e_putc(c);
}

static int
x_mv_back(int c)
{
	int col = xcp - xbuf;

	if (col == 0) {
		x_e_putc(BEL);
		return KSTD;
	}
	if (x_arg > col)
		x_arg = col;
	x_goto(xcp - x_arg);
	return KSTD;
}

static int
x_mv_forw(int c)
{
	int nleft = xep - xcp;

	if (!nleft) {
		x_e_putc(BEL);
		return KSTD;
	}
	if (x_arg > nleft)
		x_arg = nleft;
	x_goto(xcp + x_arg);
	return KSTD;
}

static int
x_search_char_forw(int c)
{
	char *cp = xcp;

	*xep = '\0';
	c = x_e_getc();
	while (x_arg--) {
		if (c < 0 ||
		    ((cp = (cp == xep) ? NULL : strchr(cp + 1, c)) == NULL &&
		    (cp = strchr(xbuf, c)) == NULL)) {
			x_e_putc(BEL);
			return KSTD;
		}
	}
	x_goto(cp);
	return KSTD;
}

static int
x_search_char_back(int c)
{
	char *cp = xcp, *p;

	c = x_e_getc();
	for (; x_arg--; cp = p)
		for (p = cp; ; ) {
			if (p-- == xbuf)
				p = xep;
			if (c < 0 || p == cp) {
				x_e_putc(BEL);
				return KSTD;
			}
			if (*p == c)
				break;
		}
	x_goto(cp);
	return KSTD;
}

static int
x_newline(int c)
{
	x_e_putc('\r');
	x_e_putc('\n');
	x_flush();
	*xep++ = '\n';
	return KEOL;
}

static int
x_end_of_text(int c)
{
	x_zotc(edchars.eof);
	x_putc('\r');
	x_putc('\n');
	x_flush();
	return KEOL;
}

static int x_beg_hist(int c) { x_load_hist(history); return KSTD;}

static int x_end_hist(int c) { x_load_hist(histptr); return KSTD;}

static int x_prev_com(int c) { x_load_hist(x_histp - x_arg); return KSTD;}

static int x_next_com(int c) { x_load_hist(x_histp + x_arg); return KSTD;}

/* Goto a particular history number obtained from argument.
 * If no argument is given history 1 is probably not what you
 * want so we'll simply go to the oldest one.
 */
static int
x_goto_hist(int c)
{
	if (x_arg_defaulted)
		x_load_hist(history);
	else
		x_load_hist(histptr + x_arg - source->line);
	return KSTD;
}

static void
x_load_hist(char **hp)
{
	int	oldsize;

	if (hp < history || hp > histptr) {
		x_e_putc(BEL);
		return;
	}
	x_histp = hp;
	oldsize = x_size_str(xbuf);
	strlcpy(xbuf, *hp, xend - xbuf);
	xbp = xbuf;
	xep = xcp = xbuf + strlen(xbuf);
	xlp_valid = false;
	if (xep > x_lastcp())
	  x_goto(xep);
	else
	  x_redraw(oldsize);
}

static int
x_nl_next_com(int c)
{
	x_nextcmd = source->line - (histptr - x_histp) + 1;
	return (x_newline(c));
}

static int
x_eot_del(int c)
{
	if (xep == xbuf && x_arg_defaulted)
		return (x_end_of_text(c));
	else
		return (x_del_char(c));
}

/* reverse incremental history search */
static int
x_search_hist(int c)
{
	int offset = -1;	/* offset of match in xbuf, else -1 */
	char pat [256+1];	/* pattern buffer */
	char *p = pat;
	u_char f;

	*p = '\0';
	while (1) {
		if (offset < 0) {
			x_e_puts("\nI-search: ");
			x_e_puts(pat);
		}
		x_flush();
		if ((c = x_e_getc()) < 0)
			return KSTD;
		f = x_tab[0][c&CHARMASK];
		if (c == CTRL('['))
			break;
		else if (f == XFUNC_search_hist)
			offset = x_search(pat, 0, offset);
		else if (f == XFUNC_del_back) {
			if (p == pat) {
				offset = -1;
				break;
			}
			if (p > pat)
				*--p = '\0';
			if (p == pat)
				offset = -1;
			else
				offset = x_search(pat, 1, offset);
			continue;
		} else if (f == XFUNC_insert) {
			/* add char to pattern */
			/* overflow check... */
			if (p >= &pat[sizeof(pat) - 1]) {
				x_e_putc(BEL);
				continue;
			}
			*p++ = c, *p = '\0';
			if (offset >= 0) {
				/* already have partial match */
				offset = x_match(xbuf, pat);
				if (offset >= 0) {
					x_goto(xbuf + offset + (p - pat) -
					    (*pat == '^'));
					continue;
				}
			}
			offset = x_search(pat, 0, offset);
		} else { /* other command */
			x_e_ungetc(c);
			break;
		}
	}
	if (offset < 0)
		x_redraw(-1);
	return KSTD;
}

/* search backward from current line */
static int
x_search(char *pat, int sameline, int offset)
{
	char **hp;
	int i;

	for (hp = x_histp - (sameline ? 0 : 1) ; hp >= history; --hp) {
		i = x_match(*hp, pat);
		if (i >= 0) {
			if (offset < 0)
				x_e_putc('\n');
			x_load_hist(hp);
			x_goto(xbuf + i + strlen(pat) - (*pat == '^'));
			return i;
		}
	}
	x_e_putc(BEL);
	x_histp = histptr;
	return -1;
}

/* return position of first match of pattern in string, else -1 */
static int
x_match(char *str, char *pat)
{
	if (*pat == '^') {
		return (strncmp(str, pat+1, strlen(pat+1)) == 0) ? 0 : -1;
	} else {
		char *q = strstr(str, pat);
		return (q == NULL) ? -1 : q - str;
	}
}

static int
x_del_line(int c)
{
	int	i, j;

	*xep = 0;
	i = xep - xbuf;
	j = x_size_str(xbuf);
	xcp = xbuf;
	x_push(i);
	xlp = xbp = xep = xbuf;
	xlp_valid = true;
	*xcp = 0;
	xmp = NULL;
	x_redraw(j);
	return KSTD;
}

static int
x_mv_end(int c)
{
	x_goto(xep);
	return KSTD;
}

static int
x_mv_begin(int c)
{
	x_goto(xbuf);
	return KSTD;
}

static int
x_draw_line(int c)
{
	x_redraw(-1);
	return KSTD;

}

/* Redraw (part of) the line.  If limit is < 0, the everything is redrawn
 * on a NEW line, otherwise limit is the screen column up to which needs
 * redrawing.
 */
static void
x_redraw(int limit)
{
	int	i, j;
	char	*cp;

	x_adj_ok = 0;
	if (limit == -1)
		x_e_putc('\n');
	else
		x_e_putc('\r');
	x_flush();
	if (xbp == xbuf) {
		pprompt(prompt + prompt_skip, 0);
		x_col = promptlen(prompt, (const char **) 0);
	}
	x_displen = xx_cols - 2 - x_col;
	xlp_valid = false;
	cp = x_lastcp();
	x_zots(xbp);
	if (xbp != xbuf || xep > xlp)
		limit = xx_cols;
	if (limit >= 0) {
		if (xep > xlp)
			i = 0;			/* we fill the line */
		else
			i = limit - (xlp - xbp);

		for (j = 0; j < i && x_col < (xx_cols - 2); j++)
			x_e_putc(' ');
		i = ' ';
		if (xep > xlp) {		/* more off screen */
			if (xbp > xbuf)
				i = '*';
			else
				i = '>';
		} else if (xbp > xbuf)
			i = '<';
		x_e_putc(i);
		j++;
		while (j--)
			x_e_putc('\b');
	}
	for (cp = xlp; cp > xcp; )
		x_bs(*--cp);
	x_adj_ok = 1;
	D__(x_flush();)
	return;
}

static int
x_transpose(int c)
{
	char	tmp;

	/* What transpose is meant to do seems to be up for debate. This
	 * is a general summary of the options; the text is abcd with the
	 * upper case character or underscore indicating the cursor position:
	 *     Who			Before	After  Before	After
	 *     at&t ksh in emacs mode:	abCd	abdC   abcd_	(bell)
	 *     at&t ksh in gmacs mode:	abCd	baCd   abcd_	abdc_
	 *     gnu emacs:		abCd	acbD   abcd_	abdc_
	 * Pdksh currently goes with GNU behavior since I believe this is the
	 * most common version of emacs, unless in gmacs mode, in which case
	 * it does the at&t ksh gmacs mode.
	 * This should really be broken up into 3 functions so users can bind
	 * to the one they want.
	 */
	if (xcp == xbuf) {
		x_e_putc(BEL);
		return KSTD;
	} else if (xcp == xep || Flag(FGMACS)) {
		if (xcp - xbuf == 1) {
			x_e_putc(BEL);
			return KSTD;
		}
		/* Gosling/Unipress emacs style: Swap two characters before the
		 * cursor, do not change cursor position
		 */
		x_bs(xcp[-1]);
		x_bs(xcp[-2]);
		x_zotc(xcp[-1]);
		x_zotc(xcp[-2]);
		tmp = xcp[-1];
		xcp[-1] = xcp[-2];
		xcp[-2] = tmp;
	} else {
		/* GNU emacs style: Swap the characters before and under the
		 * cursor, move cursor position along one.
		 */
		x_bs(xcp[-1]);
		x_zotc(xcp[0]);
		x_zotc(xcp[-1]);
		tmp = xcp[-1];
		xcp[-1] = xcp[0];
		xcp[0] = tmp;
		x_bs(xcp[0]);
		x_goto(xcp + 1);
	}
	return KSTD;
}

static int
x_literal(int c)
{
	x_curprefix = -1;
	return KSTD;
}

static int
x_meta1(int c)
{
	x_curprefix = 1;
	return KSTD;
}

static int
x_meta2(int c)
{
	x_curprefix = 2;
	return KSTD;
}

static int
x_kill(int c)
{
	int col = xcp - xbuf;
	int lastcol = xep - xbuf;
	int ndel;

	if (x_arg_defaulted)
		x_arg = lastcol;
	else if (x_arg > lastcol)
		x_arg = lastcol;
	ndel = x_arg - col;
	if (ndel < 0) {
		x_goto(xbuf + x_arg);
		ndel = -ndel;
	}
	x_delete(ndel, true);
	return KSTD;
}

static void
x_push(int nchars)
{
	char	*cp = str_nsave(xcp, nchars, AEDIT);
	if (killstack[killsp])
		afree((void *)killstack[killsp], AEDIT);
	killstack[killsp] = cp;
	killsp = (killsp + 1) % KILLSIZE;
}

static int
x_yank(int c)
{
	if (killsp == 0)
		killtp = KILLSIZE;
	else
		killtp = killsp;
	killtp --;
	if (killstack[killtp] == 0) {
		x_e_puts("\nnothing to yank");
		x_redraw(-1);
		return KSTD;
	}
	xmp = xcp;
	x_ins(killstack[killtp]);
	return KSTD;
}

static int
x_meta_yank(int c)
{
	int	len;
	if ((x_last_command != XFUNC_yank && x_last_command != XFUNC_meta_yank) ||
	    killstack[killtp] == 0) {
		killtp = killsp;
		x_e_puts("\nyank something first");
		x_redraw(-1);
		return KSTD;
	}
	len = strlen(killstack[killtp]);
	x_goto(xcp - len);
	x_delete(len, false);
	do {
		if (killtp == 0)
			killtp = KILLSIZE - 1;
		else
			killtp--;
	} while (killstack[killtp] == 0);
	x_ins(killstack[killtp]);
	return KSTD;
}

static int
x_abort(int c)
{
	/* x_zotc(c); */
	xlp = xep = xcp = xbp = xbuf;
	xlp_valid = true;
	*xcp = 0;
	return KINTR;
}

static int
x_error(int c)
{
	x_e_putc(BEL);
	return KSTD;
}

static int
x_stuffreset(int c)
{
#ifdef TIOCSTI
	(void)x_stuff(c);
	return KINTR;
#else
	x_zotc(c);
	xlp = xcp = xep = xbp = xbuf;
	xlp_valid = true;
	*xcp = 0;
	x_redraw(-1);
	return KSTD;
#endif
}

static int
x_stuff(int c)
{
#ifdef TIOCSTI
	char	ch = c;
	bool	savmode = x_mode(false);

	(void)ioctl(TTY, TIOCSTI, &ch);
	(void)x_mode(savmode);
	x_redraw(-1);
#endif
	return KSTD;
}

static char *
x_mapin(const char *cp)
{
	char *new, *op;

	op = new = str_save(cp, ATEMP);
	while (*cp) {
		/* XXX -- should handle \^ escape? */
		if (*cp == '^') {
			cp++;
			if (*cp >= '?')	/* includes '?'; ASCII */
				*op++ = CTRL(*cp);
			else {
				*op++ = '^';
				cp--;
			}
		} else
			*op++ = *cp;
		cp++;
	}
	*op = '\0';

	return new;
}

static char *
x_mapout(int c)
{
	static char buf[8];
	char *p = buf;

	if (iscntrl(c)) {
		*p++ = '^';
		*p++ = UNCTRL(c);
	} else
		*p++ = c;
	*p = 0;
	return buf;
}

static void
x_print(int prefix, int key)
{
	if (prefix == 1)
		shprintf("%s", x_mapout(x_prefix1));
	if (prefix == 2)
		shprintf("%s", x_mapout(x_prefix2));
	shprintf("%s = ", x_mapout(key));
	if (x_tab[prefix][key] != XFUNC_ins_string)
		shprintf("%s\n", x_ftab[x_tab[prefix][key]].xf_name);
	else
		shprintf("'%s'\n", x_atab[prefix][key]);
}

int
x_bind( const char *a1, const char *a2,
	int macro,		/* bind -m */
	int list)		/* bind -l */
{
	u_char f;
	int prefix, key;
	char *sp = NULL;
	char *m1, *m2;

	if (x_tab == NULL) {
		bi_errorf("cannot bind, not a tty");
		return 1;
	}

	/* List function names */
	if (list) {
		for (f = 0; f < NELEM(x_ftab); f++)
			if (x_ftab[f].xf_name &&
			    !(x_ftab[f].xf_flags & XF_NOBIND))
				shprintf("%s\n", x_ftab[f].xf_name);
		return 0;
	}

	if (a1 == NULL) {
		for (prefix = 0; prefix < X_NTABS; prefix++)
			for (key = 0; key < X_TABSZ; key++) {
				f = x_tab[prefix][key];
				if (f == XFUNC_insert || f == XFUNC_error ||
				    (macro && f != XFUNC_ins_string))
					continue;
				x_print(prefix, key);
			}
		return 0;
	}

	m1 = x_mapin(a1);
	prefix = key = 0;
	for (;; m1++) {
		key = *m1 & CHARMASK;
		if (x_tab[prefix][key] == XFUNC_meta1)
			prefix = 1;
		else if (x_tab[prefix][key] == XFUNC_meta2)
			prefix = 2;
		else
			break;
	}

	if (a2 == NULL) {
		x_print(prefix, key);
		return 0;
	}

	if (*a2 == 0)
		f = XFUNC_insert;
	else if (!macro) {
		for (f = 0; f < NELEM(x_ftab); f++)
			if (x_ftab[f].xf_name &&
			    strcmp(x_ftab[f].xf_name, a2) == 0)
				break;
		if (f == NELEM(x_ftab) || x_ftab[f].xf_flags & XF_NOBIND) {
			bi_errorf("%s: no such function", a2);
			return 1;
		}
#if 0		/* This breaks the bind commands that map arrow keys */
		if (f == XFUNC_meta1)
			x_prefix1 = key;
		if (f == XFUNC_meta2)
			x_prefix2 = key;
#endif /* 0 */
	} else {
		f = XFUNC_ins_string;
		m2 = x_mapin(a2);
		sp = str_save(m2, AEDIT);
	}

	if (x_tab[prefix][key] == XFUNC_ins_string && x_atab[prefix][key])
		afree((void *)x_atab[prefix][key], AEDIT);
	x_tab[prefix][key] = f;
	x_atab[prefix][key] = sp;

	/* Track what the user has bound so x_emacs_keys() won't toast things */
	if (f == XFUNC_insert)
		x_bound[(prefix * X_TABSZ + key) / 8] &=
		    ~(1 << ((prefix * X_TABSZ + key) % 8));
	else
		x_bound[(prefix * X_TABSZ + key) / 8] |=
		    (1 << ((prefix * X_TABSZ + key) % 8));

	return 0;
}

void
x_init_emacs(void)
{
	int i, j;
	char *locale;

	ainit(AEDIT);
	x_nextcmd = -1;

	x_tab = (u_char (*)[X_TABSZ]) alloc(sizeofN(*x_tab, X_NTABS), AEDIT);
	for (j = 0; j < X_TABSZ; j++)
		x_tab[0][j] = XFUNC_insert;
	for (i = 1; i < X_NTABS; i++)
		for (j = 0; j < X_TABSZ; j++)
			x_tab[i][j] = XFUNC_error;
	for (i = 0; i < NELEM(x_defbindings); i++)
		x_tab[(unsigned char)x_defbindings[i].xdb_tab][x_defbindings[i].xdb_char]
		    = x_defbindings[i].xdb_func;

	x_atab = (char *(*)[X_TABSZ]) alloc(sizeofN(*x_atab, X_NTABS), AEDIT);
	for (i = 1; i < X_NTABS; i++)
		for (j = 0; j < X_TABSZ; j++)
			x_atab[i][j] = NULL;

	/* Determine if we can translate meta key or use 8-bit AscII
	 * XXX - It would be nice if there was a locale attribute to
	 * determine if the locale is 7-bit or not.
	 */
	locale = setlocale(LC_CTYPE, NULL);
	if (locale == NULL || !strcmp(locale, "C") || !strcmp(locale, "POSIX"))
		Flag(FEMACSUSEMETA) = 1;
}

static void bind_if_not_bound(int p, int k, int func);

static void
bind_if_not_bound(int p, int k, int func)
{
	/* Has user already bound this key?  If so, don't override it */
	if (x_bound[((p) * X_TABSZ + (k)) / 8] &
	    (1 << (((p) * X_TABSZ + (k)) % 8)))
		return;

	x_tab[p][k] = func;
}

void
x_emacs_keys(X_chars *ec)
{
	if (ec->erase >= 0) {
		bind_if_not_bound(0, ec->erase, XFUNC_del_back);
		bind_if_not_bound(1, ec->erase, XFUNC_del_bword);
	}
	if (ec->kill >= 0)
		bind_if_not_bound(0, ec->kill, XFUNC_del_line);
	if (ec->werase >= 0)
		bind_if_not_bound(0, ec->werase, XFUNC_del_bword);
	if (ec->intr >= 0)
		bind_if_not_bound(0, ec->intr, XFUNC_abort);
	if (ec->quit >= 0)
		bind_if_not_bound(0, ec->quit, XFUNC_noop);
}

static int
x_set_mark(int c)
{
	xmp = xcp;
	return KSTD;
}

static int
x_kill_region(int c)
{
	int	rsize;
	char	*xr;

	if (xmp == NULL) {
		x_e_putc(BEL);
		return KSTD;
	}
	if (xmp > xcp) {
		rsize = xmp - xcp;
		xr = xcp;
	} else {
		rsize = xcp - xmp;
		xr = xmp;
	}
	x_goto(xr);
	x_delete(rsize, true);
	xmp = xr;
	return KSTD;
}

static int
x_xchg_point_mark(int c)
{
	char	*tmp;

	if (xmp == NULL) {
		x_e_putc(BEL);
		return KSTD;
	}
	tmp = xmp;
	xmp = xcp;
	x_goto( tmp );
	return KSTD;
}

static int
x_version(int c)
{
	char *o_xbuf = xbuf, *o_xend = xend;
	char *o_xbp = xbp, *o_xep = xep, *o_xcp = xcp;
	int lim = x_lastcp() - xbp;

	xbuf = xbp = xcp = (char *) ksh_version + 4;
	xend = xep = (char *) ksh_version + 4 + strlen(ksh_version + 4);
	x_redraw(lim);
	x_flush();

	c = x_e_getc();
	xbuf = o_xbuf;
	xend = o_xend;
	xbp = o_xbp;
	xep = o_xep;
	xcp = o_xcp;
	x_redraw(strlen(ksh_version));

	if (c < 0)
		return KSTD;
	/* This is what at&t ksh seems to do...  Very bizarre */
	if (c != ' ')
		x_e_ungetc(c);

	return KSTD;
}

static int
x_noop(int c)
{
	return KSTD;
}

#ifdef SILLY
static int
x_game_of_life(int c)
{
	char	newbuf [256+1];
	char	*ip, *op;
	int	i, len;

	i = xep - xbuf;
	*xep = 0;
	len = x_size_str(xbuf);
	xcp = xbp = xbuf;
	memmove(newbuf+1, xbuf, i);
	newbuf[0] = 'A';
	newbuf[i] = 'A';
	for (ip = newbuf+1, op = xbuf; --i >= 0; ip++, op++) {
		/*  Empty space  */
		if (*ip < '@' || *ip == '_' || *ip == 0x7F) {
			/*  Two adults, make whoopee */
			if (ip[-1] < '_' && ip[1] < '_') {
				/*  Make kid look like parents.  */
				*op = '`' + ((ip[-1] + ip[1])/2)%32;
				if (*op == 0x7F) /* Birth defect */
					*op = '`';
			}
			else
				*op = ' ';	/* nothing happens */
			continue;
		}
		/*  Child */
		if (*ip > '`') {
			/*  All alone, dies  */
			if (ip[-1] == ' ' && ip[1] == ' ')
				*op = ' ';
			else	/*  Gets older */
				*op = *ip-'`'+'@';
			continue;
		}
		/*  Adult  */
		/*  Overcrowded, dies */
		if (ip[-1] >= '@' && ip[1] >= '@') {
			*op = ' ';
			continue;
		}
		*op = *ip;
	}
	*op = 0;
	x_redraw(len);
	return KSTD;
}
#endif

/*
 *	File/command name completion routines
 */


static int
x_comp_comm(int c)
{
	do_complete(XCF_COMMAND, CT_COMPLETE);
	return KSTD;
}
static int
x_list_comm(int c)
{
	do_complete(XCF_COMMAND, CT_LIST);
	return KSTD;
}
static int
x_complete(int c)
{
	do_complete(XCF_COMMAND_FILE, CT_COMPLETE);
	return KSTD;
}
static int
x_enumerate(int c)
{
	do_complete(XCF_COMMAND_FILE, CT_LIST);
	return KSTD;
}
static int
x_comp_file(int c)
{
	do_complete(XCF_FILE, CT_COMPLETE);
	return KSTD;
}
static int
x_list_file(int c)
{
	do_complete(XCF_FILE, CT_LIST);
	return KSTD;
}
static int
x_comp_list(int c)
{
	do_complete(XCF_COMMAND_FILE, CT_COMPLIST);
	return KSTD;
}
static int
x_expand(int c)
{
	char **words;
	int nwords = 0;
	int start, end;
	int is_command;
	int i;

	nwords = x_cf_glob(XCF_FILE, xbuf, xep - xbuf, xcp - xbuf,
	    &start, &end, &words, &is_command);

	if (nwords == 0) {
		x_e_putc(BEL);
		return KSTD;
	}

	x_goto(xbuf + start);
	x_delete(end - start, false);
	for (i = 0; i < nwords;) {
		if (x_escape(words[i], strlen(words[i]), x_emacs_putbuf) < 0 ||
		    (++i < nwords && x_ins(space) < 0)) {
			x_e_putc(BEL);
			return KSTD;
		}
	}
	x_adjust();

	return KSTD;
}

/* type == 0 for list, 1 for complete and 2 for complete-list */
static void
do_complete(int flags,	/* XCF_{COMMAND,FILE,COMMAND_FILE} */
    Comp_type type)
{
	char **words;
	int nwords;
	int start, end, nlen, olen;
	int is_command;
	int completed = 0;

	nwords = x_cf_glob(flags, xbuf, xep - xbuf, xcp - xbuf,
	    &start, &end, &words, &is_command);
	/* no match */
	if (nwords == 0) {
		x_e_putc(BEL);
		return;
	}

	if (type == CT_LIST) {
		x_print_expansions(nwords, words, is_command);
		x_redraw(0);
		x_free_words(nwords, words);
		return;
	}

	olen = end - start;
	nlen = x_longest_prefix(nwords, words);
	/* complete */
	if (nwords == 1 || nlen > olen) {
		x_goto(xbuf + start);
		x_delete(olen, false);
		x_escape(words[0], nlen, x_emacs_putbuf);
		x_adjust();
		completed = 1;
	}
	/* add space if single non-dir match */
	if (nwords == 1 && words[0][nlen - 1] != '/') {
		x_ins(space);
		completed = 1;
	}

	if (type == CT_COMPLIST && !completed) {
		x_print_expansions(nwords, words, is_command);
		completed = 1;
	}

	if (completed)
		x_redraw(0);

	x_free_words(nwords, words);
}

/* NAME:
 *      x_adjust - redraw the line adjusting starting point etc.
 *
 * DESCRIPTION:
 *      This function is called when we have exceeded the bounds
 *      of the edit window.  It increments x_adj_done so that
 *      functions like x_ins and x_delete know that we have been
 *      called and can skip the x_bs() stuff which has already
 *      been done by x_redraw.
 *
 * RETURN VALUE:
 *      None
 */

static void
x_adjust(void)
{
	x_adj_done++;			/* flag the fact that we were called. */
	/*
	 * we had a problem if the prompt length > xx_cols / 2
	 */
	if ((xbp = xcp - (x_displen / 2)) < xbuf)
		xbp = xbuf;
	xlp_valid = false;
	x_redraw(xx_cols);
	x_flush();
}

static int unget_char = -1;

static void
x_e_ungetc(int c)
{
	unget_char = c;
}

static int
x_e_getc(void)
{
	int c;

	if (unget_char >= 0) {
		c = unget_char;
		unget_char = -1;
	} else {
		if (macroptr) {
			c = *macroptr++;
			if (!*macroptr)
				macroptr = (char *) 0;
		} else
			c = x_getc();
	}

	return c <= CHARMASK ? c : (c & CHARMASK);
}

static void
x_e_putc(int c)
{
	if (c == '\r' || c == '\n')
		x_col = 0;
	if (x_col < xx_cols) {
		x_putc(c);
		switch (c) {
		case BEL:
			break;
		case '\r':
		case '\n':
			break;
		case '\b':
			x_col--;
			break;
		default:
			x_col++;
			break;
		}
	}
	if (x_adj_ok && (x_col < 0 || x_col >= (xx_cols - 2)))
		x_adjust();
}

#ifdef DEBUG
static int
x_debug_info(int c)
{
	x_flush();
	shellf("\nksh debug:\n");
	shellf("\tx_col == %d,\t\tx_cols == %d,\tx_displen == %d\n",
	    x_col, xx_cols, x_displen);
	shellf("\txcp == 0x%lx,\txep == 0x%lx\n", (long) xcp, (long) xep);
	shellf("\txbp == 0x%lx,\txbuf == 0x%lx\n", (long) xbp, (long) xbuf);
	shellf("\txlp == 0x%lx\n", (long) xlp);
	shellf("\txlp == 0x%lx\n", (long) x_lastcp());
	shellf(newline);
	x_redraw(-1);
	return 0;
}
#endif

static void
x_e_puts(const char *s)
{
	int	adj = x_adj_done;

	while (*s && adj == x_adj_done)
		x_e_putc(*s++);
}

/* NAME:
 *      x_set_arg - set an arg value for next function
 *
 * DESCRIPTION:
 *      This is a simple implementation of M-[0-9].
 *
 * RETURN VALUE:
 *      KSTD
 */

static int
x_set_arg(int c)
{
	int n = 0;
	int first = 1;

	c &= CHARMASK;	/* strip command prefix */
	for (; c >= 0 && isdigit(c); c = x_e_getc(), first = 0)
		n = n * 10 + (c - '0');
	if (c < 0 || first) {
		x_e_putc(BEL);
		x_arg = 1;
		x_arg_defaulted = 1;
	} else {
		x_e_ungetc(c);
		x_arg = n;
		x_arg_defaulted = 0;
	}
	return KSTD;
}


/* Comment or uncomment the current line. */
static int
x_comment(int c)
{
	int oldsize = x_size_str(xbuf);
	int len = xep - xbuf;
	int ret = x_do_comment(xbuf, xend - xbuf, &len);

	if (ret < 0)
		x_e_putc(BEL);
	else {
		xep = xbuf + len;
		*xep = '\0';
		xcp = xbp = xbuf;
		x_redraw(oldsize);
		if (ret > 0)
			return x_newline('\n');
	}
	return KSTD;
}


/* NAME:
 *      x_prev_histword - recover word from prev command
 *
 * DESCRIPTION:
 *      This function recovers the last word from the previous
 *      command and inserts it into the current edit line.  If a
 *      numeric arg is supplied then the n'th word from the
 *      start of the previous command is used.
 *
 *      Bound to M-.
 *
 * RETURN VALUE:
 *      KSTD
 */

static int
x_prev_histword(int c)
{
	char *rcp;
	char *cp;

	cp = *histptr;
	if (!cp)
		x_e_putc(BEL);
	else if (x_arg_defaulted) {
		rcp = &cp[strlen(cp) - 1];
		/*
		 * ignore white-space after the last word
		 */
		while (rcp > cp && is_cfs(*rcp))
			rcp--;
		while (rcp > cp && !is_cfs(*rcp))
			rcp--;
		if (is_cfs(*rcp))
			rcp++;
		x_ins(rcp);
	} else {
		int c;

		rcp = cp;
		/*
		 * ignore white-space at start of line
		 */
		while (*rcp && is_cfs(*rcp))
			rcp++;
		while (x_arg-- > 1) {
			while (*rcp && !is_cfs(*rcp))
				rcp++;
			while (*rcp && is_cfs(*rcp))
				rcp++;
		}
		cp = rcp;
		while (*rcp && !is_cfs(*rcp))
			rcp++;
		c = *rcp;
		*rcp = '\0';
		x_ins(cp);
		*rcp = c;
	}
	return KSTD;
}

/* Uppercase N(1) words */
static int
x_fold_upper(int c)
{
	return x_fold_case('U');
}

/* Lowercase N(1) words */
static int
x_fold_lower(int c)
{
	return x_fold_case('L');
}

/* Lowercase N(1) words */
static int
x_fold_capitalize(int c)
{
	return x_fold_case('C');
}

/* NAME:
 *      x_fold_case - convert word to UPPER/lower/Capital case
 *
 * DESCRIPTION:
 *      This function is used to implement M-U,M-u,M-L,M-l,M-C and M-c
 *      to UPPER case, lower case or Capitalize words.
 *
 * RETURN VALUE:
 *      None
 */

static int
x_fold_case(int c)
{
	char *cp = xcp;

	if (cp == xep) {
		x_e_putc(BEL);
		return KSTD;
	}
	while (x_arg--) {
		/*
		 * first skip over any white-space
		 */
		while (cp != xep && is_mfs(*cp))
			cp++;
		/*
		 * do the first char on its own since it may be
		 * a different action than for the rest.
		 */
		if (cp != xep) {
			if (c == 'L') {		/* lowercase */
				if (isupper(*cp))
					*cp = tolower(*cp);
			} else {		/* uppercase, capitalize */
				if (islower(*cp))
					*cp = toupper(*cp);
			}
			cp++;
		}
		/*
		 * now for the rest of the word
		 */
		while (cp != xep && !is_mfs(*cp)) {
			if (c == 'U') {		/* uppercase */
				if (islower(*cp))
					*cp = toupper(*cp);
			} else {		/* lowercase, capitalize */
				if (isupper(*cp))
					*cp = tolower(*cp);
			}
			cp++;
		}
	}
	x_goto(cp);
	return KSTD;
}

/* NAME:
 *      x_lastcp - last visible char
 *
 * SYNOPSIS:
 *      x_lastcp()
 *
 * DESCRIPTION:
 *      This function returns a pointer to that  char in the
 *      edit buffer that will be the last displayed on the
 *      screen.  The sequence:
 *
 *      for (cp = x_lastcp(); cp > xcp; cp)
 *        x_bs(*--cp);
 *
 *      Will position the cursor correctly on the screen.
 *
 * RETURN VALUE:
 *      cp or NULL
 */

static char *
x_lastcp(void)
{
	char *rcp;
	int i;

	if (!xlp_valid) {
		for (i = 0, rcp = xbp; rcp < xep && i < x_displen; rcp++)
			i += x_size(*rcp);
		xlp = rcp;
	}
	xlp_valid = true;
	return (xlp);
}

#endif /* EDIT */