root/usr.bin/vi/ex/ex.c
/*      $OpenBSD: ex.c,v 1.23 2023/06/23 15:06:45 millert Exp $ */

/*-
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1992, 1993, 1994, 1995, 1996
 *      Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/time.h>

#include <bitstring.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "../common/common.h"
#include "../vi/vi.h"

#if defined(DEBUG) && defined(COMLOG)
static void     ex_comlog(SCR *, EXCMD *);
#endif
static EXCMDLIST const *
                ex_comm_search(char *, size_t);
static int      ex_discard(SCR *);
static int      ex_line(SCR *, EXCMD *, MARK *, int *, int *);
static int      ex_load(SCR *);
static void     ex_unknown(SCR *, char *, size_t);

/*
 * ex --
 *      Main ex loop.
 *
 * PUBLIC: int ex(SCR **);
 */
int
ex(SCR **spp)
{
        GS *gp;
        MSGS *mp;
        SCR *sp;
        TEXT *tp;
        u_int32_t flags;

        sp = *spp;
        gp = sp->gp;

        /* Start the ex screen. */
        if (ex_init(sp))
                return (1);

        /* Flush any saved messages. */
        while ((mp = LIST_FIRST(&gp->msgq)) != NULL) {
                gp->scr_msg(sp, mp->mtype, mp->buf, mp->len);
                LIST_REMOVE(mp, q);
                free(mp->buf);
                free(mp);
        }

        /* If reading from a file, errors should have name and line info. */
        if (F_ISSET(gp, G_SCRIPTED)) {
                gp->excmd.if_lno = 1;
                gp->excmd.if_name = "script";
        }

        /*
         * !!!
         * Initialize the text flags.  The beautify edit option historically
         * applied to ex command input read from a file.  In addition, the
         * first time a ^H was discarded from the input, there was a message,
         * "^H discarded", that was displayed.  We don't bother.
         */
        LF_INIT(TXT_BACKSLASH | TXT_CNTRLD | TXT_CR);
        for (;; ++gp->excmd.if_lno) {
                /* Display status line and flush. */
                if (F_ISSET(sp, SC_STATUS)) {
                        if (!F_ISSET(sp, SC_EX_SILENT))
                                msgq_status(sp, sp->lno, 0);
                        F_CLR(sp, SC_STATUS);
                }
                (void)ex_fflush(sp);

                /* Set the flags the user can reset. */
                if (O_ISSET(sp, O_BEAUTIFY))
                        LF_SET(TXT_BEAUTIFY);
                if (O_ISSET(sp, O_PROMPT))
                        LF_SET(TXT_PROMPT);

                /* Clear any current interrupts, and get a command. */
                CLR_INTERRUPT(sp);
                if (ex_txt(sp, &sp->tiq, ':', flags))
                        return (1);
                if (INTERRUPTED(sp)) {
                        (void)ex_puts(sp, "\n");
                        (void)ex_fflush(sp);
                        continue;
                }

                /* Initialize the command structure. */
                CLEAR_EX_PARSER(&gp->excmd);

                /*
                 * If the user entered a single carriage return, send
                 * ex_cmd() a separator -- it discards single newlines.
                 */
                tp = TAILQ_FIRST(&sp->tiq);
                if (tp->len == 0) {
                        gp->excmd.cp = " ";     /* __TK__ why not |? */
                        gp->excmd.clen = 1;
                } else {
                        gp->excmd.cp = tp->lb;
                        gp->excmd.clen = tp->len;
                }
                F_INIT(&gp->excmd, E_NRSEP);

                if (ex_cmd(sp) && F_ISSET(gp, G_SCRIPTED))
                        return (1);

                if (INTERRUPTED(sp)) {
                        CLR_INTERRUPT(sp);
                        msgq(sp, M_ERR, "Interrupted");
                }

                /* Sync recovery if changes were made. */
                if (F_ISSET(sp->ep, F_RCV_SYNC))
                        rcv_sync(sp, 0);

                /*
                 * If the last command caused a restart, or switched screens
                 * or into vi, return.
                 */
                if (F_ISSET(gp, G_SRESTART) || F_ISSET(sp, SC_SSWITCH | SC_VI)) {
                        *spp = sp;
                        break;
                }

                /* If the last command switched files, we don't care. */
                F_CLR(sp, SC_FSWITCH);

                /*
                 * If we're exiting this screen, move to the next one.  By
                 * definition, this means returning into vi, so return to the
                 * main editor loop.  The ordering is careful, don't discard
                 * the contents of sp until the end.
                 */
                if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE)) {
                        if (file_end(sp, NULL, F_ISSET(sp, SC_EXIT_FORCE)))
                                return (1);
                        *spp = screen_next(sp);
                        return (screen_end(sp));
                }
        }
        return (0);
}

/*
 * ex_cmd --
 *      The guts of the ex parser: parse and execute a string containing
 *      ex commands.
 *
 * !!!
 * This code MODIFIES the string that gets passed in, to delete quoting
 * characters, etc.  The string cannot be readonly/text space, nor should
 * you expect to use it again after ex_cmd() returns.
 *
 * !!!
 * For the fun of it, if you want to see if a vi clone got the ex argument
 * parsing right, try:
 *
 *      echo 'foo|bar' > file1; echo 'foo/bar' > file2;
 *      vi
 *      :edit +1|s/|/PIPE/|w file1| e file2|1 | s/\//SLASH/|wq
 *
 * or:  vi
 *      :set|file|append|set|file
 *
 * For extra credit, try them in a startup .exrc file.
 *
 * PUBLIC: int ex_cmd(SCR *);
 */
int
ex_cmd(SCR *sp)
{
        enum nresult nret;
        EX_PRIVATE *exp;
        EXCMD *ecp;
        GS *gp;
        MARK cur;
        recno_t lno;
        size_t arg1_len, discard, len;
        u_int32_t flags;
        long ltmp;
        int at_found, gv_found;
        int ch, cnt, delim, isaddr, namelen;
        int newscreen, notempty, tmp, vi_address;
        char *arg1, *p, *s, *t;

        gp = sp->gp;
        exp = EXP(sp);

        /*
         * We always start running the command on the top of the stack.
         * This means that *everything* must be resolved when we leave
         * this function for any reason.
         */
loop:   ecp = LIST_FIRST(&gp->ecq);

        /* If we're reading a command from a file, set up error information. */
        if (ecp->if_name != NULL) {
                gp->if_lno = ecp->if_lno;
                gp->if_name = ecp->if_name;
        }

        /*
         * If a move to the end of the file is scheduled for this command,
         * do it now.
         */
        if (F_ISSET(ecp, E_MOVETOEND)) {
                if (db_last(sp, &sp->lno))
                        goto rfail;
                sp->cno = 0;
                F_CLR(ecp, E_MOVETOEND);
        }

        /* If we found a newline, increment the count now. */
        if (F_ISSET(ecp, E_NEWLINE)) {
                ++gp->if_lno;
                ++ecp->if_lno;
                F_CLR(ecp, E_NEWLINE);
        }

        /* (Re)initialize the EXCMD structure, preserving some flags. */
        CLEAR_EX_CMD(ecp);

        /* Initialize the argument structures. */
        if (argv_init(sp, ecp))
                goto err;

        /* Initialize +cmd, saved command information. */
        arg1 = NULL;
        ecp->save_cmdlen = 0;

        /* Skip <blank>s, empty lines.  */
        for (notempty = 0; ecp->clen > 0; ++ecp->cp, --ecp->clen)
                if ((ch = *ecp->cp) == '\n') {
                        ++gp->if_lno;
                        ++ecp->if_lno;
                } else if (isblank(ch))
                        notempty = 1;
                else
                        break;

        /*
         * !!!
         * Permit extra colons at the start of the line.  Historically,
         * ex/vi allowed a single extra one.  It's simpler not to count.
         * The stripping is done here because, historically, any command
         * could have preceding colons, e.g. ":g/pattern/:p" worked.
         */
        if (ecp->clen != 0 && ch == ':') {
                notempty = 1;
                while (--ecp->clen > 0 && (ch = *++ecp->cp) == ':');
        }

        /*
         * Command lines that start with a double-quote are comments.
         *
         * !!!
         * Historically, there was no escape or delimiter for a comment, e.g.
         * :"foo|set was a single comment and nothing was output.  Since nvi
         * permits users to escape <newline> characters into command lines, we
         * have to check for that case.
         */
        if (ecp->clen != 0 && ch == '"') {
                while (--ecp->clen > 0 && *++ecp->cp != '\n');
                if (*ecp->cp == '\n') {
                        F_SET(ecp, E_NEWLINE);
                        ++ecp->cp;
                        --ecp->clen;
                }
                goto loop;
        }

        /* Skip whitespace. */
        for (; ecp->clen > 0; ++ecp->cp, --ecp->clen) {
                ch = *ecp->cp;
                if (!isblank(ch))
                        break;
        }

        /*
         * The last point at which an empty line can mean do nothing.
         *
         * !!!
         * Historically, in ex mode, lines containing only <blank> characters
         * were the same as a single <carriage-return>, i.e. a default command.
         * In vi mode, they were ignored.  In .exrc files this was a serious
         * annoyance, as vi kept trying to treat them as print commands.  We
         * ignore backward compatibility in this case, discarding lines that
         * contain only <blank> characters from .exrc files.
         *
         * !!!
         * This is where you end up when you're done a command, i.e. clen has
         * gone to zero.  Continue if there are more commands to run.
         */
        if (ecp->clen == 0 &&
            (!notempty || F_ISSET(sp, SC_VI) || F_ISSET(ecp, E_BLIGNORE))) {
                if (ex_load(sp))
                        goto rfail;
                ecp = LIST_FIRST(&gp->ecq);
                if (ecp->clen == 0)
                        goto rsuccess;
                goto loop;
        }

        /*
         * Check to see if this is a command for which we may want to move
         * the cursor back up to the previous line.  (The command :1<CR>
         * wants a <newline> separator, but the command :<CR> wants to erase
         * the command line.)  If the line is empty except for <blank>s,
         * <carriage-return> or <eof>, we'll probably want to move up.  I
         * don't think there's any way to get <blank> characters *after* the
         * command character, but this is the ex parser, and I've been wrong
         * before.
         */
        if (F_ISSET(ecp, E_NRSEP) &&
            ecp->clen != 0 && (ecp->clen != 1 || ecp->cp[0] != '\004'))
                F_CLR(ecp, E_NRSEP);

        /* Parse command addresses. */
        if (ex_range(sp, ecp, &tmp))
                goto rfail;
        if (tmp)
                goto err;

        /*
         * Skip <blank>s and any more colons (the command :3,5:print
         * worked, historically).
         */
        for (; ecp->clen > 0; ++ecp->cp, --ecp->clen) {
                ch = *ecp->cp;
                if (!isblank(ch) && ch != ':')
                        break;
        }

        /*
         * If no command, ex does the last specified of p, l, or #, and vi
         * moves to the line.  Otherwise, determine the length of the command
         * name by looking for the first non-alphabetic character.  (There
         * are a few non-alphabetic characters in command names, but they're
         * all single character commands.)  This isn't a great test, because
         * it means that, for the command ":e +cut.c file", we'll report that
         * the command "cut" wasn't known.  However, it makes ":e+35 file" work
         * correctly.
         *
         * !!!
         * Historically, lines with multiple adjacent (or <blank> separated)
         * command separators were very strange.  For example, the command
         * |||<carriage-return>, when the cursor was on line 1, displayed
         * lines 2, 3 and 5 of the file.  In addition, the command "   |  "
         * would only display the line after the next line, instead of the
         * next two lines.  No ideas why.  It worked reasonably when executed
         * from vi mode, and displayed lines 2, 3, and 4, so we do a default
         * command for each separator.
         */
#define SINGLE_CHAR_COMMANDS    "\004!#&*<=>@~"
        newscreen = 0;
        if (ecp->clen != 0 && ecp->cp[0] != '|' && ecp->cp[0] != '\n') {
                if (strchr(SINGLE_CHAR_COMMANDS, *ecp->cp)) {
                        p = ecp->cp;
                        ++ecp->cp;
                        --ecp->clen;
                        namelen = 1;
                } else {
                        for (p = ecp->cp;
                            ecp->clen > 0; --ecp->clen, ++ecp->cp)
                                if (!isalpha(*ecp->cp))
                                        break;
                        if ((namelen = ecp->cp - p) == 0) {
                                msgq(sp, M_ERR, "Unknown command name");
                                goto err;
                        }
                }

                /*
                 * !!!
                 * Historic vi permitted flags to immediately follow any
                 * subset of the 'delete' command, but then did not permit
                 * further arguments (flag, buffer, count).  Make it work.
                 * Permit further arguments for the few shreds of dignity
                 * it offers.
                 *
                 * Adding commands that start with 'd', and match "delete"
                 * up to a l, p, +, - or # character can break this code.
                 *
                 * !!!
                 * Capital letters beginning the command names ex, edit,
                 * next, previous, tag and visual (in vi mode) indicate the
                 * command should happen in a new screen.
                 */
                switch (p[0]) {
                case 'd':
                        for (s = p,
                            t = cmds[C_DELETE].name; *s == *t; ++s, ++t);
                        if (s[0] == 'l' || s[0] == 'p' || s[0] == '+' ||
                            s[0] == '-' || s[0] == '^' || s[0] == '#') {
                                len = (ecp->cp - p) - (s - p);
                                ecp->cp -= len;
                                ecp->clen += len;
                                ecp->rcmd = cmds[C_DELETE];
                                ecp->rcmd.syntax = "1bca1";
                                ecp->cmd = &ecp->rcmd;
                                goto skip_srch;
                        }
                        break;
                case 'E': case 'F': case 'N': case 'P': case 'T': case 'V':
                        newscreen = 1;
                        p[0] = tolower(p[0]);
                        break;
                }

                /*
                 * Search the table for the command.
                 *
                 * !!!
                 * Historic vi permitted the mark to immediately follow the
                 * 'k' in the 'k' command.  Make it work.
                 *
                 * !!!
                 * Historic vi permitted any flag to follow the s command, e.g.
                 * "s/e/E/|s|sgc3p" was legal.  Make the command "sgc" work.
                 * Since the following characters all have to be flags, i.e.
                 * alphabetics, we can let the s command routine return errors
                 * if it was some illegal command string.  This code will break
                 * if an "sg" or similar command is ever added.  The substitute
                 * code doesn't care if it's a "cgr" flag or a "#lp" flag that
                 * follows the 's', but we limit the choices here to "cgr" so
                 * that we get unknown command messages for wrong combinations.
                 */
                if ((ecp->cmd = ex_comm_search(p, namelen)) == NULL)
                        switch (p[0]) {
                        case 'k':
                                if (namelen == 2) {
                                        ecp->cp -= namelen - 1;
                                        ecp->clen += namelen - 1;
                                        ecp->cmd = &cmds[C_K];
                                        break;
                                }
                                goto unknown;
                        case 's':
                                for (s = p + 1, cnt = namelen; --cnt; ++s)
                                        if (s[0] != 'c' &&
                                            s[0] != 'g' && s[0] != 'r')
                                                break;
                                if (cnt == 0) {
                                        ecp->cp -= namelen - 1;
                                        ecp->clen += namelen - 1;
                                        ecp->rcmd = cmds[C_SUBSTITUTE];
                                        ecp->rcmd.fn = ex_subagain;
                                        ecp->cmd = &ecp->rcmd;
                                        break;
                                }
                                /* FALLTHROUGH */
                        default:
unknown:                        if (newscreen)
                                        p[0] = toupper(p[0]);
                                ex_unknown(sp, p, namelen);
                                goto err;
                        }

                /*
                 * The visual command has a different syntax when called
                 * from ex than when called from a vi colon command.  FMH.
                 * Make the change now, before we test for the newscreen
                 * semantic, so that we're testing the right one.
                 */
skip_srch:      if (ecp->cmd == &cmds[C_VISUAL_EX] && F_ISSET(sp, SC_VI))
                        ecp->cmd = &cmds[C_VISUAL_VI];

                /*
                 * !!!
                 * Historic vi permitted a capital 'P' at the beginning of
                 * any command that started with 'p'.  Probably wanted the
                 * P[rint] command for backward compatibility, and the code
                 * just made Preserve and Put work by accident.  Nvi uses
                 * Previous to mean previous-in-a-new-screen, so be careful.
                 */
                if (newscreen && !F_ISSET(ecp->cmd, E_NEWSCREEN) &&
                    (ecp->cmd == &cmds[C_PRINT] ||
                    ecp->cmd == &cmds[C_PRESERVE]))
                        newscreen = 0;

                /* Test for a newscreen associated with this command. */
                if (newscreen && !F_ISSET(ecp->cmd, E_NEWSCREEN))
                        goto unknown;

                /* Secure means no shell access. */
                if (F_ISSET(ecp->cmd, E_SECURE) && O_ISSET(sp, O_SECURE)) {
                        ex_emsg(sp, ecp->cmd->name, EXM_SECURE);
                        goto err;
                }

                /*
                 * Multiple < and > characters; another "feature".  Note,
                 * The string passed to the underlying function may not be
                 * nul terminated in this case.
                 */
                if ((ecp->cmd == &cmds[C_SHIFTL] && *p == '<') ||
                    (ecp->cmd == &cmds[C_SHIFTR] && *p == '>')) {
                        for (ch = *p;
                            ecp->clen > 0; --ecp->clen, ++ecp->cp)
                                if (*ecp->cp != ch)
                                        break;
                        if (argv_exp0(sp, ecp, p, ecp->cp - p))
                                goto err;
                }

                /* Set the format style flags for the next command. */
                if (ecp->cmd == &cmds[C_HASH])
                        exp->fdef = E_C_HASH;
                else if (ecp->cmd == &cmds[C_LIST])
                        exp->fdef = E_C_LIST;
                else if (ecp->cmd == &cmds[C_PRINT])
                        exp->fdef = E_C_PRINT;
                F_CLR(ecp, E_USELASTCMD);
        } else {
                /* Print is the default command. */
                ecp->cmd = &cmds[C_PRINT];

                /* Set the saved format flags. */
                F_SET(ecp, exp->fdef);

                /*
                 * !!!
                 * If no address was specified, and it's not a global command,
                 * we up the address by one.  (I have no idea why globals are
                 * exempted, but it's (ahem) historic practice.)
                 */
                if (ecp->addrcnt == 0 && !F_ISSET(sp, SC_EX_GLOBAL)) {
                        ecp->addrcnt = 1;
                        ecp->addr1.lno = sp->lno + 1;
                        ecp->addr1.cno = sp->cno;
                }

                F_SET(ecp, E_USELASTCMD);
        }

        /*
         * !!!
         * Historically, the number option applied to both ex and vi.  One
         * strangeness was that ex didn't switch display formats until a
         * command was entered, e.g. <CR>'s after the set didn't change to
         * the new format, but :1p would.
         */
        if (O_ISSET(sp, O_NUMBER)) {
                F_SET(ecp, E_OPTNUM);
                FL_SET(ecp->iflags, E_C_HASH);
        } else
                F_CLR(ecp, E_OPTNUM);

        /* Check for ex mode legality. */
        if (F_ISSET(sp, SC_EX) && (F_ISSET(ecp->cmd, E_VIONLY) || newscreen)) {
                msgq(sp, M_ERR,
                    "%s: command not available in ex mode", ecp->cmd->name);
                goto err;
        }

        /* Add standard command flags. */
        F_SET(ecp, ecp->cmd->flags);
        if (!newscreen)
                F_CLR(ecp, E_NEWSCREEN);

        /*
         * There are three normal termination cases for an ex command.  They
         * are the end of the string (ecp->clen), or unescaped (by <literal
         * next> characters) <newline> or '|' characters.  As we're now past
         * possible addresses, we can determine how long the command is, so we
         * don't have to look for all the possible terminations.  Naturally,
         * there are some exciting special cases:
         *
         * 1: The bang, global, v and the filter versions of the read and
         *    write commands are delimited by <newline>s (they can contain
         *    shell pipes).
         * 2: The ex, edit, next and visual in vi mode commands all take ex
         *    commands as their first arguments.
         * 3: The s command takes an RE as its first argument, and wants it
         *    to be specially delimited.
         *
         * Historically, '|' characters in the first argument of the ex, edit,
         * next, vi visual, and s commands didn't delimit the command.  And,
         * in the filter cases for read and write, and the bang, global and v
         * commands, they did not delimit the command at all.
         *
         * For example, the following commands were legal:
         *
         *      :edit +25|s/abc/ABC/ file.c
         *      :s/|/PIPE/
         *      :read !spell % | columnate
         *      :global/pattern/p|l
         *
         * It's not quite as simple as it sounds, however.  The command:
         *
         *      :s/a/b/|s/c/d|set
         *
         * was also legal, i.e. the historic ex parser (using the word loosely,
         * since "parser" implies some regularity of syntax) delimited the RE's
         * based on its delimiter and not anything so irretrievably vulgar as a
         * command syntax.
         *
         * Anyhow, the following code makes this all work.  First, for the
         * special cases we move past their special argument(s).  Then, we
         * do normal command processing on whatever is left.  Barf-O-Rama.
         */
        discard = 0;            /* Characters discarded from the command. */
        arg1_len = 0;
        ecp->save_cmd = ecp->cp;
        if (ecp->cmd == &cmds[C_EDIT] || ecp->cmd == &cmds[C_EX] ||
            ecp->cmd == &cmds[C_NEXT] || ecp->cmd == &cmds[C_VISUAL_VI]) {
                /*
                 * Move to the next non-whitespace character.  A '!'
                 * immediately following the command is eaten as a
                 * force flag.
                 */
                if (ecp->clen > 0 && *ecp->cp == '!') {
                        ++ecp->cp;
                        --ecp->clen;
                        FL_SET(ecp->iflags, E_C_FORCE);

                        /* Reset, don't reparse. */
                        ecp->save_cmd = ecp->cp;
                }
                for (; ecp->clen > 0; --ecp->clen, ++ecp->cp)
                        if (!isblank(*ecp->cp))
                                break;
                /*
                 * QUOTING NOTE:
                 *
                 * The historic implementation ignored all escape characters
                 * so there was no way to put a space or newline into the +cmd
                 * field.  We do a simplistic job of fixing it by moving to the
                 * first whitespace character that isn't escaped.  The escaping
                 * characters are stripped as no longer useful.
                 */
                if (ecp->clen > 0 && *ecp->cp == '+') {
                        ++ecp->cp;
                        --ecp->clen;
                        for (arg1 = p = ecp->cp;
                            ecp->clen > 0; --ecp->clen, ++ecp->cp) {
                                ch = *ecp->cp;
                                if (IS_ESCAPE(sp, ecp, ch) &&
                                    ecp->clen > 1) {
                                        ++discard;
                                        --ecp->clen;
                                        ch = *++ecp->cp;
                                } else if (isblank(ch))
                                        break;
                                *p++ = ch;
                        }
                        arg1_len = ecp->cp - arg1;

                        /* Reset, so the first argument isn't reparsed. */
                        ecp->save_cmd = ecp->cp;
                }
        } else if (ecp->cmd == &cmds[C_BANG] ||
            ecp->cmd == &cmds[C_GLOBAL] || ecp->cmd == &cmds[C_V]) {
                /*
                 * QUOTING NOTE:
                 *
                 * We use backslashes to escape <newline> characters, although
                 * this wasn't historic practice for the bang command.  It was
                 * for the global and v commands, and it's common usage when
                 * doing text insert during the command.  Escaping characters
                 * are stripped as no longer useful.
                 */
                for (p = ecp->cp; ecp->clen > 0; --ecp->clen, ++ecp->cp) {
                        ch = *ecp->cp;
                        if (ch == '\\' && ecp->clen > 1 && ecp->cp[1] == '\n') {
                                ++discard;
                                --ecp->clen;
                                ch = *++ecp->cp;

                                ++gp->if_lno;
                                ++ecp->if_lno;
                        } else if (ch == '\n')
                                break;
                        *p++ = ch;
                }
        } else if (ecp->cmd == &cmds[C_READ] || ecp->cmd == &cmds[C_WRITE]) {
                /*
                 * For write commands, if the next character is a <blank>, and
                 * the next non-blank character is a '!', it's a filter command
                 * and we want to eat everything up to the <newline>.  For read
                 * commands, if the next non-blank character is a '!', it's a
                 * filter command and we want to eat everything up to the next
                 * <newline>.  Otherwise, we're done.
                 */
                for (tmp = 0; ecp->clen > 0; --ecp->clen, ++ecp->cp) {
                        ch = *ecp->cp;
                        if (isblank(ch))
                                tmp = 1;
                        else
                                break;
                }
                if (ecp->clen > 0 && ch == '!' &&
                    (ecp->cmd == &cmds[C_READ] || tmp))
                        for (; ecp->clen > 0; --ecp->clen, ++ecp->cp)
                                if (ecp->cp[0] == '\n')
                                        break;
        } else if (ecp->cmd == &cmds[C_SUBSTITUTE]) {
                /*
                 * Move to the next non-whitespace character, we'll use it as
                 * the delimiter.  If the character isn't an alphanumeric or
                 * a '|', it's the delimiter, so parse it.  Otherwise, we're
                 * into something like ":s g", so use the special s command.
                 */
                for (; ecp->clen > 0; --ecp->clen, ++ecp->cp)
                        if (!isblank(ecp->cp[0]))
                                break;

                if (isalnum(ecp->cp[0]) || ecp->cp[0] == '|') {
                        ecp->rcmd = cmds[C_SUBSTITUTE];
                        ecp->rcmd.fn = ex_subagain;
                        ecp->cmd = &ecp->rcmd;
                } else if (ecp->clen > 0) {
                        /*
                         * QUOTING NOTE:
                         *
                         * Backslashes quote delimiter characters for RE's.
                         * The backslashes are NOT removed since they'll be
                         * used by the RE code.  Move to the third delimiter
                         * that's not escaped (or the end of the command).
                         */
                        delim = *ecp->cp;
                        ++ecp->cp;
                        --ecp->clen;
                        for (cnt = 2; ecp->clen > 0 &&
                            cnt != 0; --ecp->clen, ++ecp->cp)
                                if (ecp->cp[0] == '\\' &&
                                    ecp->clen > 1) {
                                        ++ecp->cp;
                                        --ecp->clen;
                                } else if (ecp->cp[0] == delim)
                                        --cnt;
                }
        }

        /*
         * Use normal quoting and termination rules to find the end of this
         * command.
         *
         * QUOTING NOTE:
         *
         * Historically, vi permitted ^V's to escape <newline>'s in the .exrc
         * file.  It was almost certainly a bug, but that's what bug-for-bug
         * compatibility means, Grasshopper.  Also, ^V's escape the command
         * delimiters.  Literal next quote characters in front of the newlines,
         * '|' characters or literal next characters are stripped as they're
         * no longer useful.
         */
        vi_address = ecp->clen != 0 && ecp->cp[0] != '\n';
        for (p = ecp->cp; ecp->clen > 0; --ecp->clen, ++ecp->cp) {
                ch = ecp->cp[0];
                if (IS_ESCAPE(sp, ecp, ch) && ecp->clen > 1) {
                        tmp = ecp->cp[1];
                        if (tmp == '\n' || tmp == '|') {
                                if (tmp == '\n') {
                                        ++gp->if_lno;
                                        ++ecp->if_lno;
                                }
                                ++discard;
                                --ecp->clen;
                                ++ecp->cp;
                                ch = tmp;
                        }
                } else if (ch == '\n' || ch == '|') {
                        if (ch == '\n')
                                F_SET(ecp, E_NEWLINE);
                        --ecp->clen;
                        break;
                }
                *p++ = ch;
        }

        /*
         * Save off the next command information, go back to the
         * original start of the command.
         */
        p = ecp->cp + 1;
        ecp->cp = ecp->save_cmd;
        ecp->save_cmd = p;
        ecp->save_cmdlen = ecp->clen;
        ecp->clen = ((ecp->save_cmd - ecp->cp) - 1) - discard;

        /*
         * QUOTING NOTE:
         *
         * The "set tags" command historically used a backslash, not the
         * user's literal next character, to escape whitespace.  Handle
         * it here instead of complicating the argv_exp3() code.  Note,
         * this isn't a particularly complex trap, and if backslashes were
         * legal in set commands, this would have to be much more complicated.
         */
        if (ecp->cmd == &cmds[C_SET])
                for (p = ecp->cp, len = ecp->clen; len > 0; --len, ++p)
                        if (*p == '\\')
                                *p = CH_LITERAL;

        /*
         * Set the default addresses.  It's an error to specify an address for
         * a command that doesn't take them.  If two addresses are specified
         * for a command that only takes one, lose the first one.  Two special
         * cases here, some commands take 0 or 2 addresses.  For most of them
         * (the E_ADDR2_ALL flag), 0 defaults to the entire file.  For one
         * (the `!' command, the E_ADDR2_NONE flag), 0 defaults to no lines.
         *
         * Also, if the file is empty, some commands want to use an address of
         * 0, i.e. the entire file is 0 to 0, and the default first address is
         * 0.  Otherwise, an entire file is 1 to N and the default line is 1.
         * Note, we also add the E_ADDR_ZERO flag to the command flags, for the
         * case where the 0 address is only valid if it's a default address.
         *
         * Also, set a flag if we set the default addresses.  Some commands
         * (ex: z) care if the user specified an address or if we just used
         * the current cursor.
         */
        switch (F_ISSET(ecp, E_ADDR1 | E_ADDR2 | E_ADDR2_ALL | E_ADDR2_NONE)) {
        case E_ADDR1:                           /* One address: */
                switch (ecp->addrcnt) {
                case 0:                         /* Default cursor/empty file. */
                        ecp->addrcnt = 1;
                        F_SET(ecp, E_ADDR_DEF);
                        if (F_ISSET(ecp, E_ADDR_ZERODEF)) {
                                if (db_last(sp, &lno))
                                        goto err;
                                if (lno == 0) {
                                        ecp->addr1.lno = 0;
                                        F_SET(ecp, E_ADDR_ZERO);
                                } else
                                        ecp->addr1.lno = sp->lno;
                        } else
                                ecp->addr1.lno = sp->lno;
                        ecp->addr1.cno = sp->cno;
                        break;
                case 1:
                        break;
                case 2:                         /* Lose the first address. */
                        ecp->addrcnt = 1;
                        ecp->addr1 = ecp->addr2;
                }
                break;
        case E_ADDR2_NONE:                      /* Zero/two addresses: */
                if (ecp->addrcnt == 0)          /* Default to nothing. */
                        break;
                goto two_addr;
        case E_ADDR2_ALL:                       /* Zero/two addresses: */
                if (ecp->addrcnt == 0) {        /* Default entire/empty file. */
                        F_SET(ecp, E_ADDR_DEF);
                        ecp->addrcnt = 2;
                        if (sp->ep == NULL)
                                ecp->addr2.lno = 0;
                        else if (db_last(sp, &ecp->addr2.lno))
                                goto err;
                        if (F_ISSET(ecp, E_ADDR_ZERODEF) &&
                            ecp->addr2.lno == 0) {
                                ecp->addr1.lno = 0;
                                F_SET(ecp, E_ADDR_ZERO);
                        } else
                                ecp->addr1.lno = 1;
                        ecp->addr1.cno = ecp->addr2.cno = 0;
                        F_SET(ecp, E_ADDR2_ALL);
                        break;
                }
                /* FALLTHROUGH */
        case E_ADDR2:                           /* Two addresses: */
two_addr:       switch (ecp->addrcnt) {
                case 0:                         /* Default cursor/empty file. */
                        ecp->addrcnt = 2;
                        F_SET(ecp, E_ADDR_DEF);
                        if (sp->lno == 1 &&
                            F_ISSET(ecp, E_ADDR_ZERODEF)) {
                                if (db_last(sp, &lno))
                                        goto err;
                                if (lno == 0) {
                                        ecp->addr1.lno = ecp->addr2.lno = 0;
                                        F_SET(ecp, E_ADDR_ZERO);
                                } else
                                        ecp->addr1.lno =
                                            ecp->addr2.lno = sp->lno;
                        } else
                                ecp->addr1.lno = ecp->addr2.lno = sp->lno;
                        ecp->addr1.cno = ecp->addr2.cno = sp->cno;
                        break;
                case 1:                         /* Default to first address. */
                        ecp->addrcnt = 2;
                        ecp->addr2 = ecp->addr1;
                        break;
                case 2:
                        break;
                }
                break;
        default:
                if (ecp->addrcnt)               /* Error. */
                        goto usage;
        }

        /*
         * !!!
         * The ^D scroll command historically scrolled the value of the scroll
         * option or to EOF.  It was an error if the cursor was already at EOF.
         * (Leading addresses were permitted, but were then ignored.)
         */
        if (ecp->cmd == &cmds[C_SCROLL]) {
                ecp->addrcnt = 2;
                ecp->addr1.lno = sp->lno + 1;
                ecp->addr2.lno = sp->lno + O_VAL(sp, O_SCROLL);
                ecp->addr1.cno = ecp->addr2.cno = sp->cno;
                if (db_last(sp, &lno))
                        goto err;
                if (lno != 0 && lno > sp->lno && ecp->addr2.lno > lno)
                        ecp->addr2.lno = lno;
        }

        ecp->flagoff = 0;
        for (p = ecp->cmd->syntax; *p != '\0'; ++p) {
                /*
                 * The force flag is sensitive to leading whitespace, i.e.
                 * "next !" is different from "next!".  Handle it before
                 * skipping leading <blank>s.
                 */
                if (*p == '!') {
                        if (ecp->clen > 0 && *ecp->cp == '!') {
                                ++ecp->cp;
                                --ecp->clen;
                                FL_SET(ecp->iflags, E_C_FORCE);
                        }
                        continue;
                }

                /* Skip leading <blank>s. */
                for (; ecp->clen > 0; --ecp->clen, ++ecp->cp)
                        if (!isblank(*ecp->cp))
                                break;
                if (ecp->clen == 0)
                        break;

                switch (*p) {
                case '1':                               /* +, -, #, l, p */
                        /*
                         * !!!
                         * Historically, some flags were ignored depending
                         * on where they occurred in the command line.  For
                         * example, in the command, ":3+++p--#", historic vi
                         * acted on the '#' flag, but ignored the '-' flags.
                         * It's unambiguous what the flags mean, so we just
                         * handle them regardless of the stupidity of their
                         * location.
                         */
                        for (; ecp->clen; --ecp->clen, ++ecp->cp)
                                switch (*ecp->cp) {
                                case '+':
                                        ++ecp->flagoff;
                                        break;
                                case '-':
                                case '^':
                                        --ecp->flagoff;
                                        break;
                                case '#':
                                        F_CLR(ecp, E_OPTNUM);
                                        FL_SET(ecp->iflags, E_C_HASH);
                                        exp->fdef |= E_C_HASH;
                                        break;
                                case 'l':
                                        FL_SET(ecp->iflags, E_C_LIST);
                                        exp->fdef |= E_C_LIST;
                                        break;
                                case 'p':
                                        FL_SET(ecp->iflags, E_C_PRINT);
                                        exp->fdef |= E_C_PRINT;
                                        break;
                                default:
                                        goto end_case1;
                                }
end_case1:              break;
                case '2':                               /* -, ., +, ^ */
                case '3':                               /* -, ., +, ^, = */
                        for (; ecp->clen; --ecp->clen, ++ecp->cp)
                                switch (*ecp->cp) {
                                case '-':
                                        FL_SET(ecp->iflags, E_C_DASH);
                                        break;
                                case '.':
                                        FL_SET(ecp->iflags, E_C_DOT);
                                        break;
                                case '+':
                                        FL_SET(ecp->iflags, E_C_PLUS);
                                        break;
                                case '^':
                                        FL_SET(ecp->iflags, E_C_CARAT);
                                        break;
                                case '=':
                                        if (*p == '3') {
                                                FL_SET(ecp->iflags, E_C_EQUAL);
                                                break;
                                        }
                                        /* FALLTHROUGH */
                                default:
                                        goto end_case23;
                                }
end_case23:             break;
                case 'b':                               /* buffer */
                        /*
                         * !!!
                         * Historically, "d #" was a delete with a flag, not a
                         * delete into the '#' buffer.  If the current command
                         * permits a flag, don't use one as a buffer.  However,
                         * the 'l' and 'p' flags were legal buffer names in the
                         * historic ex, and were used as buffers, not flags.
                         */
                        if ((ecp->cp[0] == '+' || ecp->cp[0] == '-' ||
                            ecp->cp[0] == '^' || ecp->cp[0] == '#') &&
                            strchr(p, '1') != NULL)
                                break;
                        /*
                         * !!!
                         * Digits can't be buffer names in ex commands, or the
                         * command "d2" would be a delete into buffer '2', and
                         * not a two-line deletion.
                         */
                        if (!isdigit(ecp->cp[0])) {
                                ecp->buffer = *ecp->cp;
                                ++ecp->cp;
                                --ecp->clen;
                                FL_SET(ecp->iflags, E_C_BUFFER);
                        }
                        break;
                case 'c':                               /* count [01+a] */
                        ++p;
                        /* Validate any signed value. */
                        if (!isdigit(*ecp->cp) && (*p != '+' ||
                            (*ecp->cp != '+' && *ecp->cp != '-')))
                                break;
                        /* If a signed value, set appropriate flags. */
                        if (*ecp->cp == '-')
                                FL_SET(ecp->iflags, E_C_COUNT_NEG);
                        else if (*ecp->cp == '+')
                                FL_SET(ecp->iflags, E_C_COUNT_POS);
                        if ((nret =
                            nget_slong(&ltmp, ecp->cp, &t, 10)) != NUM_OK) {
                                ex_badaddr(sp, NULL, A_NOTSET, nret);
                                goto err;
                        }
                        if (ltmp == 0 && *p != '0') {
                                msgq(sp, M_ERR, "Count may not be zero");
                                goto err;
                        }
                        ecp->clen -= (t - ecp->cp);
                        ecp->cp = t;

                        /*
                         * Counts as address offsets occur in commands taking
                         * two addresses.  Historic vi practice was to use
                         * the count as an offset from the *second* address.
                         *
                         * Set a count flag; some underlying commands (see
                         * join) do different things with counts than with
                         * line addresses.
                         */
                        if (*p == 'a') {
                                ecp->addr1 = ecp->addr2;
                                ecp->addr2.lno = ecp->addr1.lno + ltmp - 1;
                        } else
                                ecp->count = ltmp;
                        FL_SET(ecp->iflags, E_C_COUNT);
                        break;
                case 'f':                               /* file */
                        if (argv_exp2(sp, ecp, ecp->cp, ecp->clen))
                                goto err;
                        goto arg_cnt_chk;
                case 'l':                               /* line */
                        /*
                         * Get a line specification.
                         *
                         * If the line was a search expression, we may have
                         * changed state during the call, and we're now
                         * searching the file.  Push ourselves onto the state
                         * stack.
                         */
                        if (ex_line(sp, ecp, &cur, &isaddr, &tmp))
                                goto rfail;
                        if (tmp)
                                goto err;

                        /* Line specifications are always required. */
                        if (!isaddr) {
                                msgq_str(sp, M_ERR, ecp->cp,
                                     "%s: bad line specification");
                                goto err;
                        }
                        /*
                         * The target line should exist for these commands,
                         * but 0 is legal for them as well.
                         */
                        if (cur.lno != 0 && !db_exist(sp, cur.lno)) {
                                ex_badaddr(sp, NULL, A_EOF, NUM_OK);
                                goto err;
                        }
                        ecp->lineno = cur.lno;
                        break;
                case 'S':                               /* string, file exp. */
                        if (ecp->clen != 0) {
                                if (argv_exp1(sp, ecp, ecp->cp,
                                    ecp->clen, ecp->cmd == &cmds[C_BANG]))
                                        goto err;
                                goto addr_verify;
                        }
                        /* FALLTHROUGH */
                case 's':                               /* string */
                        if (argv_exp0(sp, ecp, ecp->cp, ecp->clen))
                                goto err;
                        goto addr_verify;
                case 'W':                               /* word string */
                        /*
                         * QUOTING NOTE:
                         *
                         * Literal next characters escape the following
                         * character.  Quoting characters are stripped here
                         * since they are no longer useful.
                         *
                         * First there was the word.
                         */
                        for (p = t = ecp->cp;
                            ecp->clen > 0; --ecp->clen, ++ecp->cp) {
                                ch = *ecp->cp;
                                if (IS_ESCAPE(sp,
                                    ecp, ch) && ecp->clen > 1) {
                                        --ecp->clen;
                                        *p++ = *++ecp->cp;
                                } else if (isblank(ch)) {
                                        ++ecp->cp;
                                        --ecp->clen;
                                        break;
                                } else
                                        *p++ = ch;
                        }
                        if (argv_exp0(sp, ecp, t, p - t))
                                goto err;

                        /* Delete intervening whitespace. */
                        for (; ecp->clen > 0;
                            --ecp->clen, ++ecp->cp) {
                                ch = *ecp->cp;
                                if (!isblank(ch))
                                        break;
                        }
                        if (ecp->clen == 0)
                                goto usage;

                        /* Followed by the string. */
                        for (p = t = ecp->cp; ecp->clen > 0;
                            --ecp->clen, ++ecp->cp, ++p) {
                                ch = *ecp->cp;
                                if (IS_ESCAPE(sp,
                                    ecp, ch) && ecp->clen > 1) {
                                        --ecp->clen;
                                        *p = *++ecp->cp;
                                } else
                                        *p = ch;
                        }
                        if (argv_exp0(sp, ecp, t, p - t))
                                goto err;
                        goto addr_verify;
                case 'w':                               /* word */
                        if (argv_exp3(sp, ecp, ecp->cp, ecp->clen))
                                goto err;
arg_cnt_chk:            if (*++p != 'N') {              /* N */
                                /*
                                 * If a number is specified, must either be
                                 * 0 or that number, if optional, and that
                                 * number, if required.
                                 */
                                tmp = *p - '0';
                                if ((*++p != 'o' || exp->argsoff != 0) &&
                                    exp->argsoff != tmp)
                                        goto usage;
                        }
                        goto addr_verify;
                default:
                        msgq(sp, M_ERR,
                            "Internal syntax table error (%s: %s)",
                            ecp->cmd->name, KEY_NAME(sp, *p));
                }
        }

        /* Skip trailing whitespace. */
        for (; ecp->clen > 0; --ecp->clen) {
                ch = *ecp->cp++;
                if (!isblank(ch))
                        break;
        }

        /*
         * There shouldn't be anything left, and no more required fields,
         * i.e neither 'l' or 'r' in the syntax string.
         */
        if (ecp->clen != 0 || strpbrk(p, "lr")) {
usage:          msgq(sp, M_ERR, "Usage: %s", ecp->cmd->usage);
                goto err;
        }

        /*
         * Verify that the addresses are legal.  Check the addresses here,
         * because this is a place where all ex addresses pass through.
         * (They don't all pass through ex_line(), for instance.)  We're
         * assuming that any non-existent line doesn't exist because it's
         * past the end-of-file.  That's a pretty good guess.
         *
         * If it's a "default vi command", an address of zero is okay.
         */
addr_verify:
        switch (ecp->addrcnt) {
        case 2:
                /*
                 * Historic ex/vi permitted commands with counts to go past
                 * EOF.  So, for example, if the file only had 5 lines, the
                 * ex command "1,6>" would fail, but the command ">300"
                 * would succeed.  Since we don't want to have to make all
                 * of the underlying commands handle random line numbers,
                 * fix it here.
                 */
                if (ecp->addr2.lno == 0) {
                        if (!F_ISSET(ecp, E_ADDR_ZERO) &&
                            (F_ISSET(sp, SC_EX) ||
                            !F_ISSET(ecp, E_USELASTCMD))) {
                                ex_badaddr(sp, ecp->cmd, A_ZERO, NUM_OK);
                                goto err;
                        }
                } else if (!db_exist(sp, ecp->addr2.lno)) {
                        if (FL_ISSET(ecp->iflags, E_C_COUNT)) {
                                if (db_last(sp, &lno))
                                        goto err;
                                ecp->addr2.lno = lno;
                        } else {
                                ex_badaddr(sp, NULL, A_EOF, NUM_OK);
                                goto err;
                        }
                }
                /* FALLTHROUGH */
        case 1:
                if (ecp->addr1.lno == 0) {
                        if (!F_ISSET(ecp, E_ADDR_ZERO) &&
                            (F_ISSET(sp, SC_EX) ||
                            !F_ISSET(ecp, E_USELASTCMD))) {
                                ex_badaddr(sp, ecp->cmd, A_ZERO, NUM_OK);
                                goto err;
                        }
                } else if (!db_exist(sp, ecp->addr1.lno)) {
                        ex_badaddr(sp, NULL, A_EOF, NUM_OK);
                        goto err;
                }
                break;
        }

        /*
         * If doing a default command and there's nothing left on the line,
         * vi just moves to the line.  For example, ":3" and ":'a,'b" just
         * move to line 3 and line 'b, respectively, but ":3|" prints line 3.
         *
         * !!!
         * In addition, IF THE LINE CHANGES, move to the first nonblank of
         * the line.
         *
         * !!!
         * This is done before the absolute mark gets set; historically,
         * "/a/,/b/" did NOT set vi's absolute mark, but "/a/,/b/d" did.
         */
        if ((F_ISSET(sp, SC_VI) || F_ISSET(ecp, E_NOPRDEF)) &&
            F_ISSET(ecp, E_USELASTCMD) && vi_address == 0) {
                switch (ecp->addrcnt) {
                case 2:
                        if (sp->lno !=
                            (ecp->addr2.lno ? ecp->addr2.lno : 1)) {
                                sp->lno =
                                    ecp->addr2.lno ? ecp->addr2.lno : 1;
                                sp->cno = 0;
                                (void)nonblank(sp, sp->lno, &sp->cno);
                        }
                        break;
                case 1:
                        if (sp->lno !=
                            (ecp->addr1.lno ? ecp->addr1.lno : 1)) {
                                sp->lno =
                                    ecp->addr1.lno ? ecp->addr1.lno : 1;
                                sp->cno = 0;
                                (void)nonblank(sp, sp->lno, &sp->cno);
                        }
                        break;
                }
                ecp->cp = ecp->save_cmd;
                ecp->clen = ecp->save_cmdlen;
                goto loop;
        }

        /*
         * Set the absolute mark -- we have to set it for vi here, in case
         * it's a compound command, e.g. ":5p|6" should set the absolute
         * mark for vi.
         */
        if (F_ISSET(ecp, E_ABSMARK)) {
                cur.lno = sp->lno;
                cur.cno = sp->cno;
                F_CLR(ecp, E_ABSMARK);
                if (mark_set(sp, ABSMARK1, &cur, 1))
                        goto err;
        }

#if defined(DEBUG) && defined(COMLOG)
        ex_comlog(sp, ecp);
#endif
        /* Increment the command count if not called from vi. */
        if (F_ISSET(sp, SC_EX))
                ++sp->ccnt;

        /*
         * If file state available, and not doing a global command,
         * log the start of an action.
         */
        if (sp->ep != NULL && !F_ISSET(sp, SC_EX_GLOBAL))
                (void)log_cursor(sp);

        /*
         * !!!
         * There are two special commands for the purposes of this code: the
         * default command (<carriage-return>) or the scrolling commands (^D
         * and <EOF>) as the first non-<blank> characters  in the line.
         *
         * If this is the first command in the command line, we received the
         * command from the ex command loop and we're talking to a tty, and
         * and there's nothing else on the command line, and it's one of the
         * special commands, we move back up to the previous line, and erase
         * the prompt character with the output.  Since ex runs in canonical
         * mode, we don't have to do anything else, a <newline> has already
         * been echoed by the tty driver.  It's OK if vi calls us -- we won't
         * be in ex mode so we'll do nothing.
         */
        if (F_ISSET(ecp, E_NRSEP)) {
                if (sp->ep != NULL &&
                    F_ISSET(sp, SC_EX) && !F_ISSET(gp, G_SCRIPTED) &&
                    (F_ISSET(ecp, E_USELASTCMD) || ecp->cmd == &cmds[C_SCROLL]))
                        gp->scr_ex_adjust(sp, EX_TERM_SCROLL);
                F_CLR(ecp, E_NRSEP);
        }

        /*
         * Call the underlying function for the ex command.
         *
         * XXX
         * Interrupts behave like errors, for now.
         */
        if (ecp->cmd->fn(sp, ecp) || INTERRUPTED(sp)) {
                if (F_ISSET(gp, G_SCRIPTED))
                        F_SET(sp, SC_EXIT_FORCE);
                goto err;
        }

#ifdef DEBUG
        /* Make sure no function left global temporary space locked. */
        if (F_ISSET(gp, G_TMP_INUSE)) {
                F_CLR(gp, G_TMP_INUSE);
                msgq(sp, M_ERR, "%s: temporary buffer not released",
                    ecp->cmd->name);
        }
#endif
        /*
         * Ex displayed the number of lines modified immediately after each
         * command, so the command "1,10d|1,10d" would display:
         *
         *      10 lines deleted
         *      10 lines deleted
         *      <autoprint line>
         *
         * Executing ex commands from vi only reported the final modified
         * lines message -- that's wrong enough that we don't match it.
         */
        if (F_ISSET(sp, SC_EX))
                mod_rpt(sp);

        /*
         * Integrate any offset parsed by the underlying command, and make
         * sure the referenced line exists.
         *
         * XXX
         * May not match historic practice (which I've never been able to
         * completely figure out.)  For example, the '=' command from vi
         * mode often got the offset wrong, and complained it was too large,
         * but didn't seem to have a problem with the cursor.  If anyone
         * complains, ask them how it's supposed to work, they might know.
         */
        if (sp->ep != NULL && ecp->flagoff) {
                if (ecp->flagoff < 0) {
                        if (sp->lno <= -ecp->flagoff) {
                                msgq(sp, M_ERR,
                                    "Flag offset to before line 1");
                                goto err;
                        }
                } else {
                        if (!NPFITS(MAX_REC_NUMBER, sp->lno, ecp->flagoff)) {
                                ex_badaddr(sp, NULL, A_NOTSET, NUM_OVER);
                                goto err;
                        }
                        if (!db_exist(sp, sp->lno + ecp->flagoff)) {
                                msgq(sp, M_ERR,
                                    "Flag offset past end-of-file");
                                goto err;
                        }
                }
                sp->lno += ecp->flagoff;
        }

        /*
         * If the command executed successfully, we may want to display a line
         * based on the autoprint option or an explicit print flag.  (Make sure
         * that there's a line to display.)  Also, the autoprint edit option is
         * turned off for the duration of global commands.
         */
        if (F_ISSET(sp, SC_EX) && sp->ep != NULL && sp->lno != 0) {
                /*
                 * The print commands have already handled the `print' flags.
                 * If so, clear them.
                 */
                if (FL_ISSET(ecp->iflags, E_CLRFLAG))
                        FL_CLR(ecp->iflags, E_C_HASH | E_C_LIST | E_C_PRINT);

                /* If hash set only because of the number option, discard it. */
                if (F_ISSET(ecp, E_OPTNUM))
                        FL_CLR(ecp->iflags, E_C_HASH);

                /*
                 * If there was an explicit flag to display the new cursor line,
                 * or autoprint is set and a change was made, display the line.
                 * If any print flags were set use them, else default to print.
                 */
                LF_INIT(FL_ISSET(ecp->iflags, E_C_HASH | E_C_LIST | E_C_PRINT));
                if (!LF_ISSET(E_C_HASH | E_C_LIST | E_C_PRINT | E_NOAUTO) &&
                    !F_ISSET(sp, SC_EX_GLOBAL) &&
                    O_ISSET(sp, O_AUTOPRINT) && F_ISSET(ecp, E_AUTOPRINT)) {

                        /* Honor the number option if autoprint is set. */
                        if (F_ISSET(ecp, E_OPTNUM))
                                LF_INIT(E_C_HASH);
                        else
                                LF_INIT(E_C_PRINT);
                }

                if (LF_ISSET(E_C_HASH | E_C_LIST | E_C_PRINT)) {
                        cur.lno = sp->lno;
                        cur.cno = 0;
                        (void)ex_print(sp, ecp, &cur, &cur, flags);
                }
        }

        /*
         * If the command had an associated "+cmd", it has to be executed
         * before we finish executing any more of this ex command.  For
         * example, consider a .exrc file that contains the following lines:
         *
         *      :set all
         *      :edit +25 file.c|s/abc/ABC/|1
         *      :3,5 print
         *
         * This can happen more than once -- the historic vi simply hung or
         * dropped core, of course.  Prepend the + command back into the
         * current command and continue.  We may have to add an additional
         * <literal next> character.  We know that it will fit because we
         * discarded at least one space and the + character.
         */
        if (arg1_len != 0) {
                /*
                 * If the last character of the + command was a <literal next>
                 * character, it would be treated differently because of the
                 * append.  Quote it, if necessary.
                 */
                if (IS_ESCAPE(sp, ecp, arg1[arg1_len - 1])) {
                        *--ecp->save_cmd = CH_LITERAL;
                        ++ecp->save_cmdlen;
                }

                ecp->save_cmd -= arg1_len;
                ecp->save_cmdlen += arg1_len;
                memmove(ecp->save_cmd, arg1, arg1_len);

                /*
                 * Any commands executed from a +cmd are executed starting at
                 * the first column of the last line of the file -- NOT the
                 * first nonblank.)  The main file startup code doesn't know
                 * that a +cmd was set, however, so it may have put us at the
                 * top of the file.  (Note, this is safe because we must have
                 * switched files to get here.)
                 */
                F_SET(ecp, E_MOVETOEND);
        }

        /* Update the current command. */
        ecp->cp = ecp->save_cmd;
        ecp->clen = ecp->save_cmdlen;

        /*
         * !!!
         * If we've changed screens or underlying files, any pending global or
         * v command, or @ buffer that has associated addresses, has to be
         * discarded.  This is historic practice for globals, and necessary for
         * @ buffers that had associated addresses.
         *
         * Otherwise, if we've changed underlying files, it's not a problem,
         * we continue with the rest of the ex command(s), operating on the
         * new file.  However, if we switch screens (either by exiting or by
         * an explicit command), we have no way of knowing where to put output
         * messages, and, since we don't control screens here, we could screw
         * up the upper layers, (e.g. we could exit/reenter a screen multiple
         * times).  So, return and continue after we've got a new screen.
         */
        if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE | SC_FSWITCH | SC_SSWITCH)) {
                at_found = gv_found = 0;
                LIST_FOREACH(ecp, &sp->gp->ecq, q)
                        switch (ecp->agv_flags) {
                        case 0:
                        case AGV_AT_NORANGE:
                                break;
                        case AGV_AT:
                                if (!at_found) {
                                        at_found = 1;
                                        msgq(sp, M_ERR,
                "@ with range running when the file/screen changed");
                                }
                                break;
                        case AGV_GLOBAL:
                        case AGV_V:
                                if (!gv_found) {
                                        gv_found = 1;
                                        msgq(sp, M_ERR,
                "Global/v command running when the file/screen changed");
                                }
                                break;
                        default:
                                abort();
                        }
                if (at_found || gv_found)
                        goto discard;
                if (F_ISSET(sp, SC_EXIT | SC_EXIT_FORCE | SC_SSWITCH))
                        goto rsuccess;
        }

        goto loop;
        /* NOTREACHED */

err:    /*
         * On command failure, we discard keys and pending commands remaining,
         * as well as any keys that were mapped and waiting.  The save_cmdlen
         * test is not necessarily correct.  If we fail early enough we don't
         * know if the entire string was a single command or not.  Guess, as
         * it's useful to know if commands other than the current one are being
         * discarded.
         */
        if (ecp->save_cmdlen == 0)
                for (; ecp->clen; --ecp->clen) {
                        ch = *ecp->cp++;
                        if (IS_ESCAPE(sp, ecp, ch) && ecp->clen > 1) {
                                --ecp->clen;
                                ++ecp->cp;
                        } else if (ch == '\n' || ch == '|') {
                                if (ecp->clen > 1)
                                        ecp->save_cmdlen = 1;
                                break;
                        }
                }
        if (ecp->save_cmdlen != 0 || LIST_FIRST(&gp->ecq) != &gp->excmd) {
discard:        msgq(sp, M_BERR,
                    "Ex command failed: pending commands discarded");
                ex_discard(sp);
        }
        if (v_event_flush(sp, CH_MAPPED))
                msgq(sp, M_BERR,
                    "Ex command failed: mapped keys discarded");

rfail:  tmp = 1;
        if (0)
rsuccess:       tmp = 0;

        /* Turn off any file name error information. */
        gp->if_name = NULL;

        /* Turn off the global bit. */
        F_CLR(sp, SC_EX_GLOBAL);

        return (tmp);
}

/*
 * ex_range --
 *      Get a line range for ex commands, or perform a vi ex address search.
 *
 * PUBLIC: int ex_range(SCR *, EXCMD *, int *);
 */
int
ex_range(SCR *sp, EXCMD *ecp, int *errp)
{
        enum { ADDR_FOUND, ADDR_NEED, ADDR_NONE } addr;
        MARK m;
        int isaddr;

        *errp = 0;

        /*
         * Parse comma or semi-colon delimited line specs.
         *
         * Semi-colon delimiters update the current address to be the last
         * address.  For example, the command
         *
         *      :3;/pattern/ecp->cp
         *
         * will search for pattern from line 3.  In addition, if ecp->cp
         * is not a valid command, the current line will be left at 3, not
         * at the original address.
         *
         * Extra addresses are discarded, starting with the first.
         *
         * !!!
         * If any addresses are missing, they default to the current line.
         * This was historically true for both leading and trailing comma
         * delimited addresses as well as for trailing semicolon delimited
         * addresses.  For consistency, we make it true for leading semicolon
         * addresses as well.
         */
        for (addr = ADDR_NONE, ecp->addrcnt = 0; ecp->clen > 0;)
                switch (*ecp->cp) {
                case '%':               /* Entire file. */
                        /* Vi ex address searches didn't permit % signs. */
                        if (F_ISSET(ecp, E_VISEARCH))
                                goto ret;

                        /* It's an error if the file is empty. */
                        if (sp->ep == NULL) {
                                ex_badaddr(sp, NULL, A_EMPTY, NUM_OK);
                                *errp = 1;
                                return (0);
                        }
                        /*
                         * !!!
                         * A percent character addresses all of the lines in
                         * the file.  Historically, it couldn't be followed by
                         * any other address.  We do it as a text substitution
                         * for simplicity.  POSIX 1003.2 is expected to follow
                         * this practice.
                         *
                         * If it's an empty file, the first line is 0, not 1.
                         */
                        if (addr == ADDR_FOUND) {
                                ex_badaddr(sp, NULL, A_COMBO, NUM_OK);
                                *errp = 1;
                                return (0);
                        }
                        if (db_last(sp, &ecp->addr2.lno))
                                return (1);
                        ecp->addr1.lno = ecp->addr2.lno == 0 ? 0 : 1;
                        ecp->addr1.cno = ecp->addr2.cno = 0;
                        ecp->addrcnt = 2;
                        addr = ADDR_FOUND;
                        ++ecp->cp;
                        --ecp->clen;
                        break;
                case ',':               /* Comma delimiter. */
                        /* Vi ex address searches didn't permit commas. */
                        if (F_ISSET(ecp, E_VISEARCH))
                                goto ret;
                        /* FALLTHROUGH */
                case ';':               /* Semi-colon delimiter. */
                        if (sp->ep == NULL) {
                                ex_badaddr(sp, NULL, A_EMPTY, NUM_OK);
                                *errp = 1;
                                return (0);
                        }
                        if (addr != ADDR_FOUND)
                                switch (ecp->addrcnt) {
                                case 0:
                                        ecp->addr1.lno = sp->lno;
                                        ecp->addr1.cno = sp->cno;
                                        ecp->addrcnt = 1;
                                        break;
                                case 2:
                                        ecp->addr1 = ecp->addr2;
                                        /* FALLTHROUGH */
                                case 1:
                                        ecp->addr2.lno = sp->lno;
                                        ecp->addr2.cno = sp->cno;
                                        ecp->addrcnt = 2;
                                        break;
                                }
                        if (*ecp->cp == ';')
                                switch (ecp->addrcnt) {
                                case 0:
                                        abort();
                                        /* NOTREACHED */
                                case 1:
                                        sp->lno = ecp->addr1.lno;
                                        sp->cno = ecp->addr1.cno;
                                        break;
                                case 2:
                                        sp->lno = ecp->addr2.lno;
                                        sp->cno = ecp->addr2.cno;
                                        break;
                                }
                        addr = ADDR_NEED;
                        /* FALLTHROUGH */
                case ' ':               /* Whitespace. */
                case '\t':              /* Whitespace. */
                        ++ecp->cp;
                        --ecp->clen;
                        break;
                default:
                        /* Get a line specification. */
                        if (ex_line(sp, ecp, &m, &isaddr, errp))
                                return (1);
                        if (*errp)
                                return (0);
                        if (!isaddr)
                                goto ret;
                        if (addr == ADDR_FOUND) {
                                ex_badaddr(sp, NULL, A_COMBO, NUM_OK);
                                *errp = 1;
                                return (0);
                        }
                        switch (ecp->addrcnt) {
                        case 0:
                                ecp->addr1 = m;
                                ecp->addrcnt = 1;
                                break;
                        case 1:
                                ecp->addr2 = m;
                                ecp->addrcnt = 2;
                                break;
                        case 2:
                                ecp->addr1 = ecp->addr2;
                                ecp->addr2 = m;
                                break;
                        }
                        addr = ADDR_FOUND;
                        break;
                }

        /*
         * !!!
         * Vi ex address searches are indifferent to order or trailing
         * semi-colons.
         */
ret:    if (F_ISSET(ecp, E_VISEARCH))
                return (0);

        if (addr == ADDR_NEED)
                switch (ecp->addrcnt) {
                case 0:
                        ecp->addr1.lno = sp->lno;
                        ecp->addr1.cno = sp->cno;
                        ecp->addrcnt = 1;
                        break;
                case 2:
                        ecp->addr1 = ecp->addr2;
                        /* FALLTHROUGH */
                case 1:
                        ecp->addr2.lno = sp->lno;
                        ecp->addr2.cno = sp->cno;
                        ecp->addrcnt = 2;
                        break;
                }

        if (ecp->addrcnt == 2 && ecp->addr2.lno < ecp->addr1.lno) {
                msgq(sp, M_ERR,
                    "The second address is smaller than the first");
                *errp = 1;
        }
        return (0);
}

/*
 * ex_line --
 *      Get a single line address specifier.
 *
 * The way the "previous context" mark worked was that any "non-relative"
 * motion set it.  While ex/vi wasn't totally consistent about this, ANY
 * numeric address, search pattern, '$', or mark reference in an address
 * was considered non-relative, and set the value.  Which should explain
 * why we're hacking marks down here.  The problem was that the mark was
 * only set if the command was called, i.e. we have to set a flag and test
 * it later.
 *
 * XXX
 * This is probably still not exactly historic practice, although I think
 * it's fairly close.
 */
static int
ex_line(SCR *sp, EXCMD *ecp, MARK *mp, int *isaddrp, int *errp)
{
        enum nresult nret;
        long total, val;
        int isneg;
        int (*sf)(SCR *, MARK *, MARK *, char *, size_t, char **, u_int);
        char *endp;

        *isaddrp = *errp = 0;
        F_CLR(ecp, E_DELTA);

        /* No addresses permitted until a file has been read in. */
        if (sp->ep == NULL && strchr("$0123456789'\\/?.+-^", *ecp->cp)) {
                ex_badaddr(sp, NULL, A_EMPTY, NUM_OK);
                *errp = 1;
                return (0);
        }

        switch (*ecp->cp) {
        case '$':                               /* Last line in the file. */
                *isaddrp = 1;
                F_SET(ecp, E_ABSMARK);

                mp->cno = 0;
                if (db_last(sp, &mp->lno))
                        return (1);
                ++ecp->cp;
                --ecp->clen;
                break;                          /* Absolute line number. */
        case '0': case '1': case '2': case '3': case '4':
        case '5': case '6': case '7': case '8': case '9':
                *isaddrp = 1;
                F_SET(ecp, E_ABSMARK);

                if ((nret = nget_slong(&val, ecp->cp, &endp, 10)) != NUM_OK) {
                        ex_badaddr(sp, NULL, A_NOTSET, nret);
                        *errp = 1;
                        return (0);
                }
                if (!NPFITS(MAX_REC_NUMBER, 0, val)) {
                        ex_badaddr(sp, NULL, A_NOTSET, NUM_OVER);
                        *errp = 1;
                        return (0);
                }
                mp->lno = val;
                mp->cno = 0;
                ecp->clen -= (endp - ecp->cp);
                ecp->cp = endp;
                break;
        case '\'':                              /* Use a mark. */
                *isaddrp = 1;
                F_SET(ecp, E_ABSMARK);

                if (ecp->clen == 1) {
                        msgq(sp, M_ERR, "No mark name supplied");
                        *errp = 1;
                        return (0);
                }
                if (mark_get(sp, ecp->cp[1], mp, M_ERR)) {
                        *errp = 1;
                        return (0);
                }
                ecp->cp += 2;
                ecp->clen -= 2;
                break;
        case '\\':                              /* Search: forward/backward. */
                /*
                 * !!!
                 * I can't find any difference between // and \/ or between
                 * ?? and \?.  Mark Horton doesn't remember there being any
                 * difference.  C'est la vie.
                 */
                if (ecp->clen < 2 ||
                    (ecp->cp[1] != '/' && ecp->cp[1] != '?')) {
                        msgq(sp, M_ERR, "\\ not followed by / or ?");
                        *errp = 1;
                        return (0);
                }
                ++ecp->cp;
                --ecp->clen;
                sf = ecp->cp[0] == '/' ? f_search : b_search;
                goto search;
        case '/':                               /* Search forward. */
                sf = f_search;
                goto search;
        case '?':                               /* Search backward. */
                sf = b_search;

search:         mp->lno = sp->lno;
                mp->cno = sp->cno;
                if (sf(sp, mp, mp, ecp->cp, ecp->clen, &endp,
                    SEARCH_MSG | SEARCH_PARSE | SEARCH_SET |
                    (F_ISSET(ecp, E_SEARCH_WMSG) ? SEARCH_WMSG : 0))) {
                        *errp = 1;
                        return (0);
                }

                /* Fix up the command pointers. */
                ecp->clen -= (endp - ecp->cp);
                ecp->cp = endp;

                *isaddrp = 1;
                F_SET(ecp, E_ABSMARK);
                break;
        case '.':                               /* Current position. */
                *isaddrp = 1;
                mp->cno = sp->cno;

                /* If an empty file, then '.' is 0, not 1. */
                if (sp->lno == 1) {
                        if (db_last(sp, &mp->lno))
                                return (1);
                        if (mp->lno != 0)
                                mp->lno = 1;
                } else
                        mp->lno = sp->lno;

                /*
                 * !!!
                 * Historically, .<number> was the same as .+<number>, i.e.
                 * the '+' could be omitted.  (This feature is found in ed
                 * as well.)
                 */
                if (ecp->clen > 1 && isdigit(ecp->cp[1]))
                        *ecp->cp = '+';
                else {
                        ++ecp->cp;
                        --ecp->clen;
                }
                break;
        }

        /* Skip trailing <blank>s. */
        for (; ecp->clen > 0 &&
            isblank(ecp->cp[0]); ++ecp->cp, --ecp->clen);

        /*
         * Evaluate any offset.  If no address yet found, the offset
         * is relative to ".".
         */
        total = 0;
        if (ecp->clen != 0 && (isdigit(ecp->cp[0]) ||
            ecp->cp[0] == '+' || ecp->cp[0] == '-' ||
            ecp->cp[0] == '^')) {
                if (!*isaddrp) {
                        *isaddrp = 1;
                        mp->lno = sp->lno;
                        mp->cno = sp->cno;
                }
                /*
                 * Evaluate an offset, defined as:
                 *
                 *              [+-^<blank>]*[<blank>]*[0-9]*
                 *
                 * The rough translation is any number of signs, optionally
                 * followed by numbers, or a number by itself, all <blank>
                 * separated.
                 *
                 * !!!
                 * All address offsets were additive, e.g. "2 2 3p" was the
                 * same as "7p", or, "/ZZZ/ 2" was the same as "/ZZZ/+2".
                 * Note, however, "2 /ZZZ/" was an error.  It was also legal
                 * to insert signs without numbers, so "3 - 2" was legal, and
                 * equal to 4.
                 *
                 * !!!
                 * Offsets were historically permitted for any line address,
                 * e.g. the command "1,2 copy 2 2 2 2" copied lines 1,2 after
                 * line 8.
                 *
                 * !!!
                 * Offsets were historically permitted for search commands,
                 * and handled as addresses: "/pattern/2 2 2" was legal, and
                 * referenced the 6th line after pattern.
                 */
                F_SET(ecp, E_DELTA);
                for (;;) {
                        for (; ecp->clen > 0 && isblank(ecp->cp[0]);
                            ++ecp->cp, --ecp->clen);
                        if (ecp->clen == 0 || (!isdigit(ecp->cp[0]) &&
                            ecp->cp[0] != '+' && ecp->cp[0] != '-' &&
                            ecp->cp[0] != '^'))
                                break;
                        if (!isdigit(ecp->cp[0]) &&
                            !isdigit(ecp->cp[1])) {
                                total += ecp->cp[0] == '+' ? 1 : -1;
                                --ecp->clen;
                                ++ecp->cp;
                        } else {
                                if (ecp->cp[0] == '-' ||
                                    ecp->cp[0] == '^') {
                                        ++ecp->cp;
                                        --ecp->clen;
                                        isneg = 1;
                                } else
                                        isneg = 0;

                                /* Get a signed long, add it to the total. */
                                if ((nret = nget_slong(&val,
                                    ecp->cp, &endp, 10)) != NUM_OK ||
                                    (nret = NADD_SLONG(total, val)) != NUM_OK) {
                                        ex_badaddr(sp, NULL, A_NOTSET, nret);
                                        *errp = 1;
                                        return (0);
                                }
                                total += isneg ? -val : val;
                                ecp->clen -= (endp - ecp->cp);
                                ecp->cp = endp;
                        }
                }
        }

        /*
         * Any value less than 0 is an error.  Make sure that the new value
         * will fit into a recno_t.
         */
        if (*isaddrp && total != 0) {
                if (total < 0) {
                        if (-total > mp->lno) {
                                msgq(sp, M_ERR,
                            "Reference to a line number less than 0");
                                *errp = 1;
                                return (0);
                        }
                } else
                        if (!NPFITS(MAX_REC_NUMBER, mp->lno, total)) {
                                ex_badaddr(sp, NULL, A_NOTSET, NUM_OVER);
                                *errp = 1;
                                return (0);
                        }
                mp->lno += total;
        }
        return (0);
}


/*
 * ex_load --
 *      Load up the next command, which may be an @ buffer or global command.
 */
static int
ex_load(SCR *sp)
{
        GS *gp;
        EXCMD *ecp;
        RANGE *rp;

        F_CLR(sp, SC_EX_GLOBAL);

        /*
         * Lose any exhausted commands.  We know that the first command
         * can't be an AGV command, which makes things a bit easier.
         */
        for (gp = sp->gp;;) {
                /*
                 * If we're back to the original structure, leave it around,
                 * but discard any allocated source name, we've returned to
                 * the beginning of the command stack.
                 */
                if ((ecp = LIST_FIRST(&gp->ecq)) == &gp->excmd) {
                        if (F_ISSET(ecp, E_NAMEDISCARD)) {
                                free(ecp->if_name);
                                ecp->if_name = NULL;
                        }
                        return (0);
                }

                /*
                 * ecp->clen will be 0 for the first discarded command, but
                 * may not be 0 for subsequent ones, e.g. if the original
                 * command was ":g/xx/@a|s/b/c/", then when we discard the
                 * command pushed on the stack by the @a, we have to resume
                 * the global command which included the substitute command.
                 */
                if (ecp->clen != 0)
                        return (0);

                /*
                 * If it's an @, global or v command, we may need to continue
                 * the command on a different line.
                 */
                if (FL_ISSET(ecp->agv_flags, AGV_ALL)) {
                        /* Discard any exhausted ranges. */
                        while ((rp = TAILQ_FIRST(&ecp->rq))) {
                                if (rp->start > rp->stop) {
                                        TAILQ_REMOVE(&ecp->rq, rp, q);
                                        free(rp);
                                } else
                                        break;
                        }

                        /* If there's another range, continue with it. */
                        if (rp)
                                break;

                        /* If it's a global/v command, fix up the last line. */
                        if (FL_ISSET(ecp->agv_flags,
                            AGV_GLOBAL | AGV_V) && ecp->range_lno != OOBLNO) {
                                if (db_exist(sp, ecp->range_lno))
                                        sp->lno = ecp->range_lno;
                                else {
                                        if (db_last(sp, &sp->lno))
                                                return (1);
                                        if (sp->lno == 0)
                                                sp->lno = 1;
                                }
                        }
                        free(ecp->o_cp);
                }

                /* Discard the EXCMD. */
                LIST_REMOVE(ecp, q);
                free(ecp);
        }

        /*
         * We only get here if it's an active @, global or v command.  Set
         * the current line number, and get a new copy of the command for
         * the parser.  Note, the original pointer almost certainly moved,
         * so we have play games.
         */
        ecp->cp = ecp->o_cp;
        memcpy(ecp->cp, ecp->cp + ecp->o_clen, ecp->o_clen);
        ecp->clen = ecp->o_clen;
        ecp->range_lno = sp->lno = rp->start++;

        if (FL_ISSET(ecp->agv_flags, AGV_GLOBAL | AGV_V))
                F_SET(sp, SC_EX_GLOBAL);
        return (0);
}

/*
 * ex_discard --
 *      Discard any pending ex commands.
 */
static int
ex_discard(SCR *sp)
{
        GS *gp;
        EXCMD *ecp;
        RANGE *rp;

        /*
         * We know the first command can't be an AGV command, so we don't
         * process it specially.  We do, however, nail the command itself.
         */
        for (gp = sp->gp; (ecp = LIST_FIRST(&gp->ecq)) != &gp->excmd;) {
                if (FL_ISSET(ecp->agv_flags, AGV_ALL)) {
                        while ((rp = TAILQ_FIRST(&ecp->rq))) {
                                TAILQ_REMOVE(&ecp->rq, rp, q);
                                free(rp);
                        }
                        free(ecp->o_cp);
                }
                LIST_REMOVE(ecp, q);
                free(ecp);
        }
        LIST_FIRST(&gp->ecq)->clen = 0;
        return (0);
}

/*
 * ex_unknown --
 *      Display an unknown command name.
 */
static void
ex_unknown(SCR *sp, char *cmd, size_t len)
{
        size_t blen;
        char *bp;

        GET_SPACE_GOTO(sp, bp, blen, len + 1);
        bp[len] = '\0';
        memcpy(bp, cmd, len);
        msgq_str(sp, M_ERR, bp, "The %s command is unknown");
        FREE_SPACE(sp, bp, blen);

alloc_err:
        return;
}

/*
 * ex_is_abbrev -
 *      The vi text input routine needs to know if ex thinks this is an
 *      [un]abbreviate command, so it can turn off abbreviations.  See
 *      the usual ranting in the vi/v_txt_ev.c:txt_abbrev() routine.
 *
 * PUBLIC: int ex_is_abbrev(char *, size_t);
 */
int
ex_is_abbrev(char *name, size_t len)
{
        EXCMDLIST const *cp;

        return ((cp = ex_comm_search(name, len)) != NULL &&
            (cp == &cmds[C_ABBR] || cp == &cmds[C_UNABBREVIATE]));
}

/*
 * ex_is_unmap -
 *      The vi text input routine needs to know if ex thinks this is an
 *      unmap command, so it can turn off input mapping.  See the usual
 *      ranting in the vi/v_txt_ev.c:txt_unmap() routine.
 *
 * PUBLIC: int ex_is_unmap(char *, size_t);
 */
int
ex_is_unmap(char *name, size_t len)
{
        EXCMDLIST const *cp;

        /*
         * The command the vi input routines are really interested in
         * is "unmap!", not just unmap.
         */
        if (name[len - 1] != '!')
                return (0);
        --len;
        return ((cp = ex_comm_search(name, len)) != NULL &&
            cp == &cmds[C_UNMAP]);
}

/*
 * ex_comm_search --
 *      Search for a command name.
 */
static EXCMDLIST const *
ex_comm_search(char *name, size_t len)
{
        EXCMDLIST const *cp;

        for (cp = cmds; cp->name != NULL; ++cp) {
                if (cp->name[0] > name[0])
                        return (NULL);
                if (cp->name[0] != name[0])
                        continue;
                if (!memcmp(name, cp->name, len))
                        return (cp);
        }
        return (NULL);
}

/*
 * ex_badaddr --
 *      Display a bad address message.
 *
 * PUBLIC: void ex_badaddr
 * PUBLIC:(SCR *, EXCMDLIST const *, enum badaddr, enum nresult);
 */
void
ex_badaddr(SCR *sp, EXCMDLIST const *cp, enum badaddr ba, enum nresult nret)
{
        recno_t lno;

        switch (nret) {
        case NUM_OK:
                break;
        case NUM_ERR:
                msgq(sp, M_SYSERR, NULL);
                return;
        case NUM_OVER:
                msgq(sp, M_ERR, "Address value overflow");
                return;
        case NUM_UNDER:
                msgq(sp, M_ERR, "Address value underflow");
                return;
        }

        /*
         * When encountering an address error, tell the user if there's no
         * underlying file, that's the real problem.
         */
        if (sp->ep == NULL) {
                ex_emsg(sp, cp != NULL ? cp->name : NULL, EXM_NOFILEYET);
                return;
        }

        switch (ba) {
        case A_COMBO:
                msgq(sp, M_ERR, "Illegal address combination");
                break;
        case A_EOF:
                if (db_last(sp, &lno))
                        return;
                if (lno != 0) {
                        msgq(sp, M_ERR,
                            "Illegal address: only %lu lines in the file",
                            lno);
                        break;
                }
                /* FALLTHROUGH */
        case A_EMPTY:
                msgq(sp, M_ERR, "Illegal address: the file is empty");
                break;
        case A_NOTSET:
                abort();
                /* NOTREACHED */
        case A_ZERO:
                msgq(sp, M_ERR,
                    "The %s command doesn't permit an address of 0",
                    cp->name);
                break;
        }
        return;
}

#if defined(DEBUG) && defined(COMLOG)
/*
 * ex_comlog --
 *      Log ex commands.
 */
static void
ex_comlog(SCR *sp, EXCMD *ecp)
{
        TRACE(sp, "ecmd: %s", ecp->cmd->name);
        if (ecp->addrcnt > 0) {
                TRACE(sp, " a1 %d", ecp->addr1.lno);
                if (ecp->addrcnt > 1)
                        TRACE(sp, " a2: %d", ecp->addr2.lno);
        }
        if (ecp->lineno)
                TRACE(sp, " line %d", ecp->lineno);
        if (ecp->flags)
                TRACE(sp, " flags 0x%x", ecp->flags);
        if (F_ISSET(&exc, E_BUFFER))
                TRACE(sp, " buffer %c", ecp->buffer);
        if (ecp->argc)
                for (cnt = 0; cnt < ecp->argc; ++cnt)
                        TRACE(sp, " arg %d: {%s}", cnt, ecp->argv[cnt]->bp);
        TRACE(sp, "\n");
}
#endif