Merge commit 'svn-vim'

[MacVim/KaoriYa.git] / src / ex_eval.c

/* vi:set ts=8 sts=4 sw=4:
 *
 * VIM - Vi IMproved    by Bram Moolenaar
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

/*
 * ex_eval.c: functions for Ex command line for the +eval feature.
 */

#include "vim.h"

#if defined(FEAT_EVAL) || defined(PROTO)

static void     free_msglist __ARGS((struct msglist *l));
static int      throw_exception __ARGS((void *, int, char_u *));
static char_u   *get_end_emsg __ARGS((struct condstack *cstack));

/*
 * Exception handling terms:
 *
 *      :try            ":try" command          \
 *          ...         try block               |
 *      :catch RE       ":catch" command        |
 *          ...         catch clause            |- try conditional
 *      :finally        ":finally" command      |
 *          ...         finally clause          |
 *      :endtry         ":endtry" command       /
 *
 * The try conditional may have any number of catch clauses and at most one
 * finally clause.  A ":throw" command can be inside the try block, a catch
 * clause, the finally clause, or in a function called or script sourced from
 * there or even outside the try conditional.  Try conditionals may be nested.
 */

/*
 * Configuration whether an exception is thrown on error or interrupt.  When
 * the preprocessor macros below evaluate to FALSE, an error (did_emsg) or
 * interrupt (got_int) under an active try conditional terminates the script
 * after the non-active finally clauses of all active try conditionals have been
 * executed.  Otherwise, errors and/or interrupts are converted into catchable
 * exceptions (did_throw additionally set), which terminate the script only if
 * not caught.  For user exceptions, only did_throw is set.  (Note: got_int can
 * be set asyncronously afterwards by a SIGINT, so did_throw && got_int is not
 * a reliant test that the exception currently being thrown is an interrupt
 * exception.  Similarly, did_emsg can be set afterwards on an error in an
 * (unskipped) conditional command inside an inactive conditional, so did_throw
 * && did_emsg is not a reliant test that the exception currently being thrown
 * is an error exception.)  -  The macros can be defined as expressions checking
 * for a variable that is allowed to be changed during execution of a script.
 */
#if 0
/* Expressions used for testing during the development phase. */
# define THROW_ON_ERROR         (!eval_to_number("$VIMNOERRTHROW"))
# define THROW_ON_INTERRUPT     (!eval_to_number("$VIMNOINTTHROW"))
# define THROW_TEST
#else
/* Values used for the Vim release. */
# define THROW_ON_ERROR         TRUE
# define THROW_ON_INTERRUPT     TRUE
#endif

static void     catch_exception __ARGS((except_T *excp));
static void     finish_exception __ARGS((except_T *excp));
static void     discard_exception __ARGS((except_T *excp, int was_finished));
static void     report_pending __ARGS((int action, int pending, void *value));

/*
 * When several errors appear in a row, setting "force_abort" is delayed until
 * the failing command returned.  "cause_abort" is set to TRUE meanwhile, in
 * order to indicate that situation.  This is useful when "force_abort" was set
 * during execution of a function call from an expression: the aborting of the
 * expression evaluation is done without producing any error messages, but all
 * error messages on parsing errors during the expression evaluation are given
 * (even if a try conditional is active).
 */
static int cause_abort = FALSE;

/*
 * Return TRUE when immediately aborting on error, or when an interrupt
 * occurred or an exception was thrown but not caught.  Use for ":{range}call"
 * to check whether an aborted function that does not handle a range itself
 * should be called again for the next line in the range.  Also used for
 * cancelling expression evaluation after a function call caused an immediate
 * abort.  Note that the first emsg() call temporarily resets "force_abort"
 * until the throw point for error messages has been reached.  That is, during
 * cancellation of an expression evaluation after an aborting function call or
 * due to a parsing error, aborting() always returns the same value.
 */
    int
aborting()
{
    return (did_emsg && force_abort) || got_int || did_throw;
}

/*
 * The value of "force_abort" is temporarily reset by the first emsg() call
 * during an expression evaluation, and "cause_abort" is used instead.  It might
 * be necessary to restore "force_abort" even before the throw point for the
 * error message has been reached.  update_force_abort() should be called then.
 */
    void
update_force_abort()
{
    if (cause_abort)
        force_abort = TRUE;
}

/*
 * Return TRUE if a command with a subcommand resulting in "retcode" should
 * abort the script processing.  Can be used to suppress an autocommand after
 * execution of a failing subcommand as long as the error message has not been
 * displayed and actually caused the abortion.
 */
    int
should_abort(retcode)
    int         retcode;
{
    return ((retcode == FAIL && trylevel != 0 && !emsg_silent) || aborting());
}

/*
 * Return TRUE if a function with the "abort" flag should not be considered
 * ended on an error.  This means that parsing commands is continued in order
 * to find finally clauses to be executed, and that some errors in skipped
 * commands are still reported.
 */
    int
aborted_in_try()
{
    /* This function is only called after an error.  In this case, "force_abort"
     * determines whether searching for finally clauses is necessary. */
    return force_abort;
}

/*
 * cause_errthrow(): Cause a throw of an error exception if appropriate.
 * Return TRUE if the error message should not be displayed by emsg().
 * Sets "ignore", if the emsg() call should be ignored completely.
 *
 * When several messages appear in the same command, the first is usually the
 * most specific one and used as the exception value.  The "severe" flag can be
 * set to TRUE, if a later but severer message should be used instead.
 */
    int
cause_errthrow(mesg, severe, ignore)
    char_u      *mesg;
    int         severe;
    int         *ignore;
{
    struct msglist *elem;
    struct msglist **plist;

    /*
     * Do nothing when displaying the interrupt message or reporting an
     * uncaught exception (which has already been discarded then) at the top
     * level.  Also when no exception can be thrown.  The message will be
     * displayed by emsg().
     */
    if (suppress_errthrow)
        return FALSE;

    /*
     * If emsg() has not been called previously, temporarily reset
     * "force_abort" until the throw point for error messages has been
     * reached.  This ensures that aborting() returns the same value for all
     * errors that appear in the same command.  This means particularly that
     * for parsing errors during expression evaluation emsg() will be called
     * multiply, even when the expression is evaluated from a finally clause
     * that was activated due to an aborting error, interrupt, or exception.
     */
    if (!did_emsg)
    {
        cause_abort = force_abort;
        force_abort = FALSE;
    }

    /*
     * If no try conditional is active and no exception is being thrown and
     * there has not been an error in a try conditional or a throw so far, do
     * nothing (for compatibility of non-EH scripts).  The message will then
     * be displayed by emsg().  When ":silent!" was used and we are not
     * currently throwing an exception, do nothing.  The message text will
     * then be stored to v:errmsg by emsg() without displaying it.
     */
    if (((trylevel == 0 && !cause_abort) || emsg_silent) && !did_throw)
        return FALSE;

    /*
     * Ignore an interrupt message when inside a try conditional or when an
     * exception is being thrown or when an error in a try conditional or
     * throw has been detected previously.  This is important in order that an
     * interrupt exception is catchable by the innermost try conditional and
     * not replaced by an interrupt message error exception.
     */
    if (mesg == (char_u *)_(e_interr))
    {
        *ignore = TRUE;
        return TRUE;
    }

    /*
     * Ensure that all commands in nested function calls and sourced files
     * are aborted immediately.
     */
    cause_abort = TRUE;

    /*
     * When an exception is being thrown, some commands (like conditionals) are
     * not skipped.  Errors in those commands may affect what of the subsequent
     * commands are regarded part of catch and finally clauses.  Catching the
     * exception would then cause execution of commands not intended by the
     * user, who wouldn't even get aware of the problem.  Therefor, discard the
     * exception currently being thrown to prevent it from being caught.  Just
     * execute finally clauses and terminate.
     */
    if (did_throw)
    {
        /* When discarding an interrupt exception, reset got_int to prevent the
         * same interrupt being converted to an exception again and discarding
         * the error exception we are about to throw here. */
        if (current_exception->type == ET_INTERRUPT)
            got_int = FALSE;
        discard_current_exception();
    }

#ifdef THROW_TEST
    if (!THROW_ON_ERROR)
    {
        /*
         * Print error message immediately without searching for a matching
         * catch clause; just finally clauses are executed before the script
         * is terminated.
         */
        return FALSE;
    }
    else
#endif
    {
        /*
         * Prepare the throw of an error exception, so that everything will
         * be aborted (except for executing finally clauses), until the error
         * exception is caught; if still uncaught at the top level, the error
         * message will be displayed and the script processing terminated
         * then.  -  This function has no access to the conditional stack.
         * Thus, the actual throw is made after the failing command has
         * returned.  -  Throw only the first of several errors in a row, except
         * a severe error is following.
         */
        if (msg_list != NULL)
        {
            plist = msg_list;
            while (*plist != NULL)
                plist = &(*plist)->next;

            elem = (struct msglist *)alloc((unsigned)sizeof(struct msglist));
            if (elem == NULL)
            {
                suppress_errthrow = TRUE;
                EMSG(_(e_outofmem));
            }
            else
            {
                elem->msg = vim_strsave(mesg);
                if (elem->msg == NULL)
                {
                    vim_free(elem);
                    suppress_errthrow = TRUE;
                    EMSG(_(e_outofmem));
                }
                else
                {
                    elem->next = NULL;
                    elem->throw_msg = NULL;
                    *plist = elem;
                    if (plist == msg_list || severe)
                    {
                        char_u      *tmsg;

                        /* Skip the extra "Vim " prefix for message "E458". */
                        tmsg = elem->msg;
                        if (STRNCMP(tmsg, "Vim E", 5) == 0
                                && VIM_ISDIGIT(tmsg[5])
                                && VIM_ISDIGIT(tmsg[6])
                                && VIM_ISDIGIT(tmsg[7])
                                && tmsg[8] == ':'
                                && tmsg[9] == ' ')
                            (*msg_list)->throw_msg = &tmsg[4];
                        else
                            (*msg_list)->throw_msg = tmsg;
                    }
                }
            }
        }
        return TRUE;
    }
}

/*
 * Free a "msg_list" and the messages it contains.
 */
    static void
free_msglist(l)
    struct msglist  *l;
{
    struct msglist  *messages, *next;

    messages = l;
    while (messages != NULL)
    {
        next = messages->next;
        vim_free(messages->msg);
        vim_free(messages);
        messages = next;
    }
}

/*
 * Throw the message specified in the call to cause_errthrow() above as an
 * error exception.  If cstack is NULL, postpone the throw until do_cmdline()
 * has returned (see do_one_cmd()).
 */
    void
do_errthrow(cstack, cmdname)
    struct condstack    *cstack;
    char_u              *cmdname;
{
    /*
     * Ensure that all commands in nested function calls and sourced files
     * are aborted immediately.
     */
    if (cause_abort)
    {
        cause_abort = FALSE;
        force_abort = TRUE;
    }

    /* If no exception is to be thrown or the conversion should be done after
     * returning to a previous invocation of do_one_cmd(), do nothing. */
    if (msg_list == NULL || *msg_list == NULL)
        return;

    if (throw_exception(*msg_list, ET_ERROR, cmdname) == FAIL)
        free_msglist(*msg_list);
    else
    {
        if (cstack != NULL)
            do_throw(cstack);
        else
            need_rethrow = TRUE;
    }
    *msg_list = NULL;
}

/*
 * do_intthrow(): Replace the current exception by an interrupt or interrupt
 * exception if appropriate.  Return TRUE if the current exception is discarded,
 * FALSE otherwise.
 */
    int
do_intthrow(cstack)
    struct condstack    *cstack;
{
    /*
     * If no interrupt occurred or no try conditional is active and no exception
     * is being thrown, do nothing (for compatibility of non-EH scripts).
     */
    if (!got_int || (trylevel == 0 && !did_throw))
        return FALSE;

#ifdef THROW_TEST       /* avoid warning for condition always true */
    if (!THROW_ON_INTERRUPT)
    {
        /*
         * The interrupt aborts everything except for executing finally clauses.
         * Discard any user or error or interrupt exception currently being
         * thrown.
         */
        if (did_throw)
            discard_current_exception();
    }
    else
#endif
    {
        /*
         * Throw an interrupt exception, so that everything will be aborted
         * (except for executing finally clauses), until the interrupt exception
         * is caught; if still uncaught at the top level, the script processing
         * will be terminated then.  -  If an interrupt exception is already
         * being thrown, do nothing.
         *
         */
        if (did_throw)
        {
            if (current_exception->type == ET_INTERRUPT)
                return FALSE;

            /* An interrupt exception replaces any user or error exception. */
            discard_current_exception();
        }
        if (throw_exception("Vim:Interrupt", ET_INTERRUPT, NULL) != FAIL)
            do_throw(cstack);
    }

    return TRUE;
}


/*
 * Throw a new exception.  Return FAIL when out of memory or it was tried to
 * throw an illegal user exception.  "value" is the exception string for a user
 * or interrupt exception, or points to a message list in case of an error
 * exception.
 */
    static int
throw_exception(value, type, cmdname)
    void        *value;
    int         type;
    char_u      *cmdname;
{
    except_T    *excp;
    char_u      *p, *mesg, *val;
    int         cmdlen;

    /*
     * Disallow faking Interrupt or error exceptions as user exceptions.  They
     * would be treated differently from real interrupt or error exceptions when
     * no active try block is found, see do_cmdline().
     */
    if (type == ET_USER)
    {
        if (STRNCMP((char_u *)value, "Vim", 3) == 0 &&
                (((char_u *)value)[3] == NUL || ((char_u *)value)[3] == ':' ||
                 ((char_u *)value)[3] == '('))
        {
            EMSG(_("E608: Cannot :throw exceptions with 'Vim' prefix"));
            goto fail;
        }
    }

    excp = (except_T *)alloc((unsigned)sizeof(except_T));
    if (excp == NULL)
        goto nomem;

    if (type == ET_ERROR)
    {
        /* Store the original message and prefix the exception value with
         * "Vim:" or, if a command name is given, "Vim(cmdname):". */
        excp->messages = (struct msglist *)value;
        mesg = excp->messages->throw_msg;
        if (cmdname != NULL && *cmdname != NUL)
        {
            cmdlen = (int)STRLEN(cmdname);
            excp->value = vim_strnsave((char_u *)"Vim(",
                                           4 + cmdlen + 2 + (int)STRLEN(mesg));
            if (excp->value == NULL)
                goto nomem;
            STRCPY(&excp->value[4], cmdname);
            STRCPY(&excp->value[4 + cmdlen], "):");
            val = excp->value + 4 + cmdlen + 2;
        }
        else
        {
            excp->value = vim_strnsave((char_u *)"Vim:", 4 + (int)STRLEN(mesg));
            if (excp->value == NULL)
                goto nomem;
            val = excp->value + 4;
        }

        /* msg_add_fname may have been used to prefix the message with a file
         * name in quotes.  In the exception value, put the file name in
         * parentheses and move it to the end. */
        for (p = mesg; ; p++)
        {
            if (*p == NUL
                    || (*p == 'E'
                        && VIM_ISDIGIT(p[1])
                        && (p[2] == ':'
                            || (VIM_ISDIGIT(p[2])
                                && (p[3] == ':'
                                    || (VIM_ISDIGIT(p[3])
                                        && p[4] == ':'))))))
            {
                if (*p == NUL || p == mesg)
                    STRCAT(val, mesg);  /* 'E123' missing or at beginning */
                else
                {
                    /* '"filename" E123: message text' */
                    if (mesg[0] != '"' || p-2 < &mesg[1] ||
                            p[-2] != '"' || p[-1] != ' ')
                        /* "E123:" is part of the file name. */
                        continue;

                    STRCAT(val, p);
                    p[-2] = NUL;
                    sprintf((char *)(val + STRLEN(p)), " (%s)", &mesg[1]);
                    p[-2] = '"';
                }
                break;
            }
        }
    }
    else
        excp->value = value;

    excp->type = type;
    excp->throw_name = vim_strsave(sourcing_name == NULL
                                              ? (char_u *)"" : sourcing_name);
    if (excp->throw_name == NULL)
    {
        if (type == ET_ERROR)
            vim_free(excp->value);
        goto nomem;
    }
    excp->throw_lnum = sourcing_lnum;

    if (p_verbose >= 13 || debug_break_level > 0)
    {
        int     save_msg_silent = msg_silent;

        if (debug_break_level > 0)
            msg_silent = FALSE;         /* display messages */
        else
            verbose_enter();
        ++no_wait_return;
        if (debug_break_level > 0 || *p_vfile == NUL)
            msg_scroll = TRUE;      /* always scroll up, don't overwrite */

        smsg((char_u *)_("Exception thrown: %s"), excp->value);
        msg_puts((char_u *)"\n");   /* don't overwrite this either */

        if (debug_break_level > 0 || *p_vfile == NUL)
            cmdline_row = msg_row;
        --no_wait_return;
        if (debug_break_level > 0)
            msg_silent = save_msg_silent;
        else
            verbose_leave();
    }

    current_exception = excp;
    return OK;

nomem:
    vim_free(excp);
    suppress_errthrow = TRUE;
    EMSG(_(e_outofmem));
fail:
    current_exception = NULL;
    return FAIL;
}

/*
 * Discard an exception.  "was_finished" is set when the exception has been
 * caught and the catch clause has been ended normally.
 */
    static void
discard_exception(excp, was_finished)
    except_T            *excp;
    int                 was_finished;
{
    char_u              *saved_IObuff;

    if (excp == NULL)
    {
        EMSG(_(e_internal));
        return;
    }

    if (p_verbose >= 13 || debug_break_level > 0)
    {
        int     save_msg_silent = msg_silent;

        saved_IObuff = vim_strsave(IObuff);
        if (debug_break_level > 0)
            msg_silent = FALSE;         /* display messages */
        else
            verbose_enter();
        ++no_wait_return;
        if (debug_break_level > 0 || *p_vfile == NUL)
            msg_scroll = TRUE;      /* always scroll up, don't overwrite */
        smsg(was_finished
                    ? (char_u *)_("Exception finished: %s")
                    : (char_u *)_("Exception discarded: %s"),
                excp->value);
        msg_puts((char_u *)"\n");   /* don't overwrite this either */
        if (debug_break_level > 0 || *p_vfile == NUL)
            cmdline_row = msg_row;
        --no_wait_return;
        if (debug_break_level > 0)
            msg_silent = save_msg_silent;
        else
            verbose_leave();
        STRCPY(IObuff, saved_IObuff);
        vim_free(saved_IObuff);
    }
    if (excp->type != ET_INTERRUPT)
        vim_free(excp->value);
    if (excp->type == ET_ERROR)
        free_msglist(excp->messages);
    vim_free(excp->throw_name);
    vim_free(excp);
}

/*
 * Discard the exception currently being thrown.
 */
    void
discard_current_exception()
{
    discard_exception(current_exception, FALSE);
    current_exception = NULL;
    did_throw = FALSE;
    need_rethrow = FALSE;
}

/*
 * Put an exception on the caught stack.
 */
    static void
catch_exception(excp)
    except_T    *excp;
{
    excp->caught = caught_stack;
    caught_stack = excp;
    set_vim_var_string(VV_EXCEPTION, excp->value, -1);
    if (*excp->throw_name != NUL)
    {
        if (excp->throw_lnum != 0)
            vim_snprintf((char *)IObuff, IOSIZE, _("%s, line %ld"),
                                    excp->throw_name, (long)excp->throw_lnum);
        else
            vim_snprintf((char *)IObuff, IOSIZE, "%s", excp->throw_name);
        set_vim_var_string(VV_THROWPOINT, IObuff, -1);
    }
    else
        /* throw_name not set on an exception from a command that was typed. */
        set_vim_var_string(VV_THROWPOINT, NULL, -1);

    if (p_verbose >= 13 || debug_break_level > 0)
    {
        int     save_msg_silent = msg_silent;

        if (debug_break_level > 0)
            msg_silent = FALSE;         /* display messages */
        else
            verbose_enter();
        ++no_wait_return;
        if (debug_break_level > 0 || *p_vfile == NUL)
            msg_scroll = TRUE;      /* always scroll up, don't overwrite */

        smsg((char_u *)_("Exception caught: %s"), excp->value);
        msg_puts((char_u *)"\n");   /* don't overwrite this either */

        if (debug_break_level > 0 || *p_vfile == NUL)
            cmdline_row = msg_row;
        --no_wait_return;
        if (debug_break_level > 0)
            msg_silent = save_msg_silent;
        else
            verbose_leave();
    }
}

/*
 * Remove an exception from the caught stack.
 */
    static void
finish_exception(excp)
    except_T    *excp;
{
    if (excp != caught_stack)
        EMSG(_(e_internal));
    caught_stack = caught_stack->caught;
    if (caught_stack != NULL)
    {
        set_vim_var_string(VV_EXCEPTION, caught_stack->value, -1);
        if (*caught_stack->throw_name != NUL)
        {
            if (caught_stack->throw_lnum != 0)
                vim_snprintf((char *)IObuff, IOSIZE,
                        _("%s, line %ld"), caught_stack->throw_name,
                        (long)caught_stack->throw_lnum);
            else
                vim_snprintf((char *)IObuff, IOSIZE, "%s",
                                                    caught_stack->throw_name);
            set_vim_var_string(VV_THROWPOINT, IObuff, -1);
        }
        else
            /* throw_name not set on an exception from a command that was
             * typed. */
            set_vim_var_string(VV_THROWPOINT, NULL, -1);
    }
    else
    {
        set_vim_var_string(VV_EXCEPTION, NULL, -1);
        set_vim_var_string(VV_THROWPOINT, NULL, -1);
    }

    /* Discard the exception, but use the finish message for 'verbose'. */
    discard_exception(excp, TRUE);
}

/*
 * Flags specifying the message displayed by report_pending.
 */
#define RP_MAKE         0
#define RP_RESUME       1
#define RP_DISCARD      2

/*
 * Report information about something pending in a finally clause if required by
 * the 'verbose' option or when debugging.  "action" tells whether something is
 * made pending or something pending is resumed or discarded.  "pending" tells
 * what is pending.  "value" specifies the return value for a pending ":return"
 * or the exception value for a pending exception.
 */
    static void
report_pending(action, pending, value)
    int         action;
    int         pending;
    void        *value;
{
    char_u      *mesg;
    char        *s;
    int         save_msg_silent;


    switch (action)
    {
        case RP_MAKE:
            mesg = (char_u *)_("%s made pending");
            break;
        case RP_RESUME:
            mesg = (char_u *)_("%s resumed");
            break;
        /* case RP_DISCARD: */
        default:
            mesg = (char_u *)_("%s discarded");
            break;
    }

    switch (pending)
    {
        case CSTP_NONE:
            return;

        case CSTP_CONTINUE:
            s = ":continue";
            break;
        case CSTP_BREAK:
            s = ":break";
            break;
        case CSTP_FINISH:
            s = ":finish";
            break;
        case CSTP_RETURN:
            /* ":return" command producing value, allocated */
            s = (char *)get_return_cmd(value);
            break;

        default:
            if (pending & CSTP_THROW)
            {
                vim_snprintf((char *)IObuff, IOSIZE,
                                                (char *)mesg, _("Exception"));
                mesg = vim_strnsave(IObuff, (int)STRLEN(IObuff) + 4);
                STRCAT(mesg, ": %s");
                s = (char *)((except_T *)value)->value;
            }
            else if ((pending & CSTP_ERROR) && (pending & CSTP_INTERRUPT))
                s = _("Error and interrupt");
            else if (pending & CSTP_ERROR)
                s = _("Error");
            else /* if (pending & CSTP_INTERRUPT) */
                s = _("Interrupt");
    }

    save_msg_silent = msg_silent;
    if (debug_break_level > 0)
        msg_silent = FALSE;     /* display messages */
    ++no_wait_return;
    msg_scroll = TRUE;          /* always scroll up, don't overwrite */
    smsg(mesg, (char_u *)s);
    msg_puts((char_u *)"\n");   /* don't overwrite this either */
    cmdline_row = msg_row;
    --no_wait_return;
    if (debug_break_level > 0)
        msg_silent = save_msg_silent;

    if (pending == CSTP_RETURN)
        vim_free(s);
    else if (pending & CSTP_THROW)
        vim_free(mesg);
}

/*
 * If something is made pending in a finally clause, report it if required by
 * the 'verbose' option or when debugging.
 */
    void
report_make_pending(pending, value)
    int         pending;
    void        *value;
{
    if (p_verbose >= 14 || debug_break_level > 0)
    {
        if (debug_break_level <= 0)
            verbose_enter();
        report_pending(RP_MAKE, pending, value);
        if (debug_break_level <= 0)
            verbose_leave();
    }
}

/*
 * If something pending in a finally clause is resumed at the ":endtry", report
 * it if required by the 'verbose' option or when debugging.
 */
    void
report_resume_pending(pending, value)
    int         pending;
    void        *value;
{
    if (p_verbose >= 14 || debug_break_level > 0)
    {
        if (debug_break_level <= 0)
            verbose_enter();
        report_pending(RP_RESUME, pending, value);
        if (debug_break_level <= 0)
            verbose_leave();
    }
}

/*
 * If something pending in a finally clause is discarded, report it if required
 * by the 'verbose' option or when debugging.
 */
    void
report_discard_pending(pending, value)
    int         pending;
    void        *value;
{
    if (p_verbose >= 14 || debug_break_level > 0)
    {
        if (debug_break_level <= 0)
            verbose_enter();
        report_pending(RP_DISCARD, pending, value);
        if (debug_break_level <= 0)
            verbose_leave();
    }
}


/*
 * ":if".
 */
    void
ex_if(eap)
    exarg_T     *eap;
{
    int         error;
    int         skip;
    int         result;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_idx == CSTACK_LEN - 1)
        eap->errmsg = (char_u *)N_("E579: :if nesting too deep");
    else
    {
        ++cstack->cs_idx;
        cstack->cs_flags[cstack->cs_idx] = 0;

        /*
         * Don't do something after an error, interrupt, or throw, or when there
         * is a surrounding conditional and it was not active.
         */
        skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
                && !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));

        result = eval_to_bool(eap->arg, &error, &eap->nextcmd, skip);

        if (!skip && !error)
        {
            if (result)
                cstack->cs_flags[cstack->cs_idx] = CSF_ACTIVE | CSF_TRUE;
        }
        else
            /* set TRUE, so this conditional will never get active */
            cstack->cs_flags[cstack->cs_idx] = CSF_TRUE;
    }
}

/*
 * ":endif".
 */
    void
ex_endif(eap)
    exarg_T     *eap;
{
    did_endif = TRUE;
    if (eap->cstack->cs_idx < 0
            || (eap->cstack->cs_flags[eap->cstack->cs_idx]
                                           & (CSF_WHILE | CSF_FOR | CSF_TRY)))
        eap->errmsg = (char_u *)N_("E580: :endif without :if");
    else
    {
        /*
         * When debugging or a breakpoint was encountered, display the debug
         * prompt (if not already done).  This shows the user that an ":endif"
         * is executed when the ":if" or a previous ":elseif" was not TRUE.
         * Handle a ">quit" debug command as if an interrupt had occurred before
         * the ":endif".  That is, throw an interrupt exception if appropriate.
         * Doing this here prevents an exception for a parsing error being
         * discarded by throwing the interrupt exception later on.
         */
        if (!(eap->cstack->cs_flags[eap->cstack->cs_idx] & CSF_TRUE)
                                                    && dbg_check_skipped(eap))
            (void)do_intthrow(eap->cstack);

        --eap->cstack->cs_idx;
    }
}

/*
 * ":else" and ":elseif".
 */
    void
ex_else(eap)
    exarg_T     *eap;
{
    int         error;
    int         skip;
    int         result;
    struct condstack    *cstack = eap->cstack;

    /*
     * Don't do something after an error, interrupt, or throw, or when there is
     * a surrounding conditional and it was not active.
     */
    skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
            && !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));

    if (cstack->cs_idx < 0
            || (cstack->cs_flags[cstack->cs_idx]
                                           & (CSF_WHILE | CSF_FOR | CSF_TRY)))
    {
        if (eap->cmdidx == CMD_else)
        {
            eap->errmsg = (char_u *)N_("E581: :else without :if");
            return;
        }
        eap->errmsg = (char_u *)N_("E582: :elseif without :if");
        skip = TRUE;
    }
    else if (cstack->cs_flags[cstack->cs_idx] & CSF_ELSE)
    {
        if (eap->cmdidx == CMD_else)
        {
            eap->errmsg = (char_u *)N_("E583: multiple :else");
            return;
        }
        eap->errmsg = (char_u *)N_("E584: :elseif after :else");
        skip = TRUE;
    }

    /* if skipping or the ":if" was TRUE, reset ACTIVE, otherwise set it */
    if (skip || cstack->cs_flags[cstack->cs_idx] & CSF_TRUE)
    {
        if (eap->errmsg == NULL)
            cstack->cs_flags[cstack->cs_idx] = CSF_TRUE;
        skip = TRUE;    /* don't evaluate an ":elseif" */
    }
    else
        cstack->cs_flags[cstack->cs_idx] = CSF_ACTIVE;

    /*
     * When debugging or a breakpoint was encountered, display the debug prompt
     * (if not already done).  This shows the user that an ":else" or ":elseif"
     * is executed when the ":if" or previous ":elseif" was not TRUE.  Handle
     * a ">quit" debug command as if an interrupt had occurred before the
     * ":else" or ":elseif".  That is, set "skip" and throw an interrupt
     * exception if appropriate.  Doing this here prevents that an exception
     * for a parsing errors is discarded when throwing the interrupt exception
     * later on.
     */
    if (!skip && dbg_check_skipped(eap) && got_int)
    {
        (void)do_intthrow(cstack);
        skip = TRUE;
    }

    if (eap->cmdidx == CMD_elseif)
    {
        result = eval_to_bool(eap->arg, &error, &eap->nextcmd, skip);
        /* When throwing error exceptions, we want to throw always the first
         * of several errors in a row.  This is what actually happens when
         * a conditional error was detected above and there is another failure
         * when parsing the expression.  Since the skip flag is set in this
         * case, the parsing error will be ignored by emsg(). */

        if (!skip && !error)
        {
            if (result)
                cstack->cs_flags[cstack->cs_idx] = CSF_ACTIVE | CSF_TRUE;
            else
                cstack->cs_flags[cstack->cs_idx] = 0;
        }
        else if (eap->errmsg == NULL)
            /* set TRUE, so this conditional will never get active */
            cstack->cs_flags[cstack->cs_idx] = CSF_TRUE;
    }
    else
        cstack->cs_flags[cstack->cs_idx] |= CSF_ELSE;
}

/*
 * Handle ":while" and ":for".
 */
    void
ex_while(eap)
    exarg_T     *eap;
{
    int         error;
    int         skip;
    int         result;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_idx == CSTACK_LEN - 1)
        eap->errmsg = (char_u *)N_("E585: :while/:for nesting too deep");
    else
    {
        /*
         * The loop flag is set when we have jumped back from the matching
         * ":endwhile" or ":endfor".  When not set, need to initialise this
         * cstack entry.
         */
        if ((cstack->cs_lflags & CSL_HAD_LOOP) == 0)
        {
            ++cstack->cs_idx;
            ++cstack->cs_looplevel;
            cstack->cs_line[cstack->cs_idx] = -1;
        }
        cstack->cs_flags[cstack->cs_idx] =
                               eap->cmdidx == CMD_while ? CSF_WHILE : CSF_FOR;

        /*
         * Don't do something after an error, interrupt, or throw, or when
         * there is a surrounding conditional and it was not active.
         */
        skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
                && !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));
        if (eap->cmdidx == CMD_while)
        {
            /*
             * ":while bool-expr"
             */
            result = eval_to_bool(eap->arg, &error, &eap->nextcmd, skip);
        }
        else
        {
            void *fi;

            /*
             * ":for var in list-expr"
             */
            if ((cstack->cs_lflags & CSL_HAD_LOOP) != 0)
            {
                /* Jumping here from a ":continue" or ":endfor": use the
                 * previously evaluated list. */
                fi = cstack->cs_forinfo[cstack->cs_idx];
                error = FALSE;
            }
            else
            {
                /* Evaluate the argument and get the info in a structure. */
                fi = eval_for_line(eap->arg, &error, &eap->nextcmd, skip);
                cstack->cs_forinfo[cstack->cs_idx] = fi;
            }

            /* use the element at the start of the list and advance */
            if (!error && fi != NULL && !skip)
                result = next_for_item(fi, eap->arg);
            else
                result = FALSE;

            if (!result)
            {
                free_for_info(fi);
                cstack->cs_forinfo[cstack->cs_idx] = NULL;
            }
        }

        /*
         * If this cstack entry was just initialised and is active, set the
         * loop flag, so do_cmdline() will set the line number in cs_line[].
         * If executing the command a second time, clear the loop flag.
         */
        if (!skip && !error && result)
        {
            cstack->cs_flags[cstack->cs_idx] |= (CSF_ACTIVE | CSF_TRUE);
            cstack->cs_lflags ^= CSL_HAD_LOOP;
        }
        else
        {
            cstack->cs_lflags &= ~CSL_HAD_LOOP;
            /* If the ":while" evaluates to FALSE or ":for" is past the end of
             * the list, show the debug prompt at the ":endwhile"/":endfor" as
             * if there was a ":break" in a ":while"/":for" evaluating to
             * TRUE. */
            if (!skip && !error)
                cstack->cs_flags[cstack->cs_idx] |= CSF_TRUE;
        }
    }
}

/*
 * ":continue"
 */
    void
ex_continue(eap)
    exarg_T     *eap;
{
    int         idx;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0)
        eap->errmsg = (char_u *)N_("E586: :continue without :while or :for");
    else
    {
        /* Try to find the matching ":while".  This might stop at a try
         * conditional not in its finally clause (which is then to be executed
         * next).  Therefor, inactivate all conditionals except the ":while"
         * itself (if reached). */
        idx = cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, FALSE);
        if (idx >= 0 && (cstack->cs_flags[idx] & (CSF_WHILE | CSF_FOR)))
        {
            rewind_conditionals(cstack, idx, CSF_TRY, &cstack->cs_trylevel);

            /*
             * Set CSL_HAD_CONT, so do_cmdline() will jump back to the
             * matching ":while".
             */
            cstack->cs_lflags |= CSL_HAD_CONT;  /* let do_cmdline() handle it */
        }
        else
        {
            /* If a try conditional not in its finally clause is reached first,
             * make the ":continue" pending for execution at the ":endtry". */
            cstack->cs_pending[idx] = CSTP_CONTINUE;
            report_make_pending(CSTP_CONTINUE, NULL);
        }
    }
}

/*
 * ":break"
 */
    void
ex_break(eap)
    exarg_T     *eap;
{
    int         idx;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0)
        eap->errmsg = (char_u *)N_("E587: :break without :while or :for");
    else
    {
        /* Inactivate conditionals until the matching ":while" or a try
         * conditional not in its finally clause (which is then to be
         * executed next) is found.  In the latter case, make the ":break"
         * pending for execution at the ":endtry". */
        idx = cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, TRUE);
        if (idx >= 0 && !(cstack->cs_flags[idx] & (CSF_WHILE | CSF_FOR)))
        {
            cstack->cs_pending[idx] = CSTP_BREAK;
            report_make_pending(CSTP_BREAK, NULL);
        }
    }
}

/*
 * ":endwhile" and ":endfor"
 */
    void
ex_endwhile(eap)
    exarg_T     *eap;
{
    struct condstack    *cstack = eap->cstack;
    int                 idx;
    char_u              *err;
    int                 csf;
    int                 fl;

    if (eap->cmdidx == CMD_endwhile)
    {
        err = e_while;
        csf = CSF_WHILE;
    }
    else
    {
        err = e_for;
        csf = CSF_FOR;
    }

    if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0)
        eap->errmsg = err;
    else
    {
        fl =  cstack->cs_flags[cstack->cs_idx];
        if (!(fl & csf))
        {
            /* If we are in a ":while" or ":for" but used the wrong endloop
             * command, do not rewind to the next enclosing ":for"/":while". */
            if (fl & CSF_WHILE)
                eap->errmsg = (char_u *)_("E732: Using :endfor with :while");
            else if (fl & CSF_FOR)
                eap->errmsg = (char_u *)_("E733: Using :endwhile with :for");
        }
        if (!(fl & (CSF_WHILE | CSF_FOR)))
        {
            if (!(fl & CSF_TRY))
                eap->errmsg = e_endif;
            else if (fl & CSF_FINALLY)
                eap->errmsg = e_endtry;
            /* Try to find the matching ":while" and report what's missing. */
            for (idx = cstack->cs_idx; idx > 0; --idx)
            {
                fl =  cstack->cs_flags[idx];
                if ((fl & CSF_TRY) && !(fl & CSF_FINALLY))
                {
                    /* Give up at a try conditional not in its finally clause.
                     * Ignore the ":endwhile"/":endfor". */
                    eap->errmsg = err;
                    return;
                }
                if (fl & csf)
                    break;
            }
            /* Cleanup and rewind all contained (and unclosed) conditionals. */
            (void)cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, FALSE);
            rewind_conditionals(cstack, idx, CSF_TRY, &cstack->cs_trylevel);
        }

        /*
         * When debugging or a breakpoint was encountered, display the debug
         * prompt (if not already done).  This shows the user that an
         * ":endwhile"/":endfor" is executed when the ":while" was not TRUE or
         * after a ":break".  Handle a ">quit" debug command as if an
         * interrupt had occurred before the ":endwhile"/":endfor".  That is,
         * throw an interrupt exception if appropriate.  Doing this here
         * prevents that an exception for a parsing error is discarded when
         * throwing the interrupt exception later on.
         */
        else if (cstack->cs_flags[cstack->cs_idx] & CSF_TRUE
                && !(cstack->cs_flags[cstack->cs_idx] & CSF_ACTIVE)
                && dbg_check_skipped(eap))
            (void)do_intthrow(cstack);

        /*
         * Set loop flag, so do_cmdline() will jump back to the matching
         * ":while" or ":for".
         */
        cstack->cs_lflags |= CSL_HAD_ENDLOOP;
    }
}


/*
 * ":throw expr"
 */
    void
ex_throw(eap)
    exarg_T     *eap;
{
    char_u      *arg = eap->arg;
    char_u      *value;

    if (*arg != NUL && *arg != '|' && *arg != '\n')
        value = eval_to_string_skip(arg, &eap->nextcmd, eap->skip);
    else
    {
        EMSG(_(e_argreq));
        value = NULL;
    }

    /* On error or when an exception is thrown during argument evaluation, do
     * not throw. */
    if (!eap->skip && value != NULL)
    {
        if (throw_exception(value, ET_USER, NULL) == FAIL)
            vim_free(value);
        else
            do_throw(eap->cstack);
    }
}

/*
 * Throw the current exception through the specified cstack.  Common routine
 * for ":throw" (user exception) and error and interrupt exceptions.  Also
 * used for rethrowing an uncaught exception.
 */
    void
do_throw(cstack)
    struct condstack    *cstack;
{
    int         idx;
    int         inactivate_try = FALSE;

    /*
     * Cleanup and inactivate up to the next surrounding try conditional that
     * is not in its finally clause.  Normally, do not inactivate the try
     * conditional itself, so that its ACTIVE flag can be tested below.  But
     * if a previous error or interrupt has not been converted to an exception,
     * inactivate the try conditional, too, as if the conversion had been done,
     * and reset the did_emsg or got_int flag, so this won't happen again at
     * the next surrounding try conditional.
     */
    if (did_emsg && !THROW_ON_ERROR)
    {
        inactivate_try = TRUE;
        did_emsg = FALSE;
    }
    if (got_int && !THROW_ON_INTERRUPT)
    {
        inactivate_try = TRUE;
        got_int = FALSE;
    }
    idx = cleanup_conditionals(cstack, 0, inactivate_try);
    if (idx >= 0)
    {
        /*
         * If this try conditional is active and we are before its first
         * ":catch", set THROWN so that the ":catch" commands will check
         * whether the exception matches.  When the exception came from any of
         * the catch clauses, it will be made pending at the ":finally" (if
         * present) and rethrown at the ":endtry".  This will also happen if
         * the try conditional is inactive.  This is the case when we are
         * throwing an exception due to an error or interrupt on the way from
         * a preceding ":continue", ":break", ":return", ":finish", error or
         * interrupt (not converted to an exception) to the finally clause or
         * from a preceding throw of a user or error or interrupt exception to
         * the matching catch clause or the finally clause.
         */
        if (!(cstack->cs_flags[idx] & CSF_CAUGHT))
        {
            if (cstack->cs_flags[idx] & CSF_ACTIVE)
                cstack->cs_flags[idx] |= CSF_THROWN;
            else
                /* THROWN may have already been set for a catchable exception
                 * that has been discarded.  Ensure it is reset for the new
                 * exception. */
                cstack->cs_flags[idx] &= ~CSF_THROWN;
        }
        cstack->cs_flags[idx] &= ~CSF_ACTIVE;
        cstack->cs_exception[idx] = current_exception;
    }
#if 0
    /* TODO: Add optimization below.  Not yet done because of interface
     * problems to eval.c and ex_cmds2.c. (Servatius) */
    else
    {
        /*
         * There are no catch clauses to check or finally clauses to execute.
         * End the current script or function.  The exception will be rethrown
         * in the caller.
         */
        if (getline_equal(eap->getline, eap->cookie, get_func_line))
            current_funccal->returned = TRUE;
        elseif (eap->get_func_line == getsourceline)
            ((struct source_cookie *)eap->cookie)->finished = TRUE;
    }
#endif

    did_throw = TRUE;
}

/*
 * ":try"
 */
    void
ex_try(eap)
    exarg_T     *eap;
{
    int         skip;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_idx == CSTACK_LEN - 1)
        eap->errmsg = (char_u *)N_("E601: :try nesting too deep");
    else
    {
        ++cstack->cs_idx;
        ++cstack->cs_trylevel;
        cstack->cs_flags[cstack->cs_idx] = CSF_TRY;
        cstack->cs_pending[cstack->cs_idx] = CSTP_NONE;

        /*
         * Don't do something after an error, interrupt, or throw, or when there
         * is a surrounding conditional and it was not active.
         */
        skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
                && !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));

        if (!skip)
        {
            /* Set ACTIVE and TRUE.  TRUE means that the corresponding ":catch"
             * commands should check for a match if an exception is thrown and
             * that the finally clause needs to be executed. */
            cstack->cs_flags[cstack->cs_idx] |= CSF_ACTIVE | CSF_TRUE;

            /*
             * ":silent!", even when used in a try conditional, disables
             * displaying of error messages and conversion of errors to
             * exceptions.  When the silent commands again open a try
             * conditional, save "emsg_silent" and reset it so that errors are
             * again converted to exceptions.  The value is restored when that
             * try conditional is left.  If it is left normally, the commands
             * following the ":endtry" are again silent.  If it is left by
             * a ":continue", ":break", ":return", or ":finish", the commands
             * executed next are again silent.  If it is left due to an
             * aborting error, an interrupt, or an exception, restoring
             * "emsg_silent" does not matter since we are already in the
             * aborting state and/or the exception has already been thrown.
             * The effect is then just freeing the memory that was allocated
             * to save the value.
             */
            if (emsg_silent)
            {
                eslist_T        *elem;

                elem = (eslist_T *)alloc((unsigned)sizeof(struct eslist_elem));
                if (elem == NULL)
                    EMSG(_(e_outofmem));
                else
                {
                    elem->saved_emsg_silent = emsg_silent;
                    elem->next = cstack->cs_emsg_silent_list;
                    cstack->cs_emsg_silent_list = elem;
                    cstack->cs_flags[cstack->cs_idx] |= CSF_SILENT;
                    emsg_silent = 0;
                }
            }
        }

    }
}

/*
 * ":catch /{pattern}/" and ":catch"
 */
    void
ex_catch(eap)
    exarg_T     *eap;
{
    int         idx = 0;
    int         give_up = FALSE;
    int         skip = FALSE;
    int         caught = FALSE;
    char_u      *end;
    int         save_char = 0;
    char_u      *save_cpo;
    regmatch_T  regmatch;
    int         prev_got_int;
    struct condstack    *cstack = eap->cstack;
    char_u      *pat;

    if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0)
    {
        eap->errmsg = (char_u *)N_("E603: :catch without :try");
        give_up = TRUE;
    }
    else
    {
        if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY))
        {
            /* Report what's missing if the matching ":try" is not in its
             * finally clause. */
            eap->errmsg = get_end_emsg(cstack);
            skip = TRUE;
        }
        for (idx = cstack->cs_idx; idx > 0; --idx)
            if (cstack->cs_flags[idx] & CSF_TRY)
                break;
        if (cstack->cs_flags[idx] & CSF_FINALLY)
        {
            /* Give up for a ":catch" after ":finally" and ignore it.
             * Just parse. */
            eap->errmsg = (char_u *)N_("E604: :catch after :finally");
            give_up = TRUE;
        }
        else
            rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
                                                       &cstack->cs_looplevel);
    }

    if (ends_excmd(*eap->arg))  /* no argument, catch all errors */
    {
        pat = (char_u *)".*";
        end = NULL;
        eap->nextcmd = find_nextcmd(eap->arg);
    }
    else
    {
        pat = eap->arg + 1;
        end = skip_regexp(pat, *eap->arg, TRUE, NULL);
    }

    if (!give_up)
    {
        /*
         * Don't do something when no exception has been thrown or when the
         * corresponding try block never got active (because of an inactive
         * surrounding conditional or after an error or interrupt or throw).
         */
        if (!did_throw || !(cstack->cs_flags[idx] & CSF_TRUE))
            skip = TRUE;

        /*
         * Check for a match only if an exception is thrown but not caught by
         * a previous ":catch".  An exception that has replaced a discarded
         * exception is not checked (THROWN is not set then).
         */
        if (!skip && (cstack->cs_flags[idx] & CSF_THROWN)
                && !(cstack->cs_flags[idx] & CSF_CAUGHT))
        {
            if (end != NULL && *end != NUL && !ends_excmd(*skipwhite(end + 1)))
            {
                EMSG(_(e_trailing));
                return;
            }

            /* When debugging or a breakpoint was encountered, display the
             * debug prompt (if not already done) before checking for a match.
             * This is a helpful hint for the user when the regular expression
             * matching fails.  Handle a ">quit" debug command as if an
             * interrupt had occurred before the ":catch".  That is, discard
             * the original exception, replace it by an interrupt exception,
             * and don't catch it in this try block. */
            if (!dbg_check_skipped(eap) || !do_intthrow(cstack))
            {
                /* Terminate the pattern and avoid the 'l' flag in 'cpoptions'
                 * while compiling it. */
                if (end != NULL)
                {
                    save_char = *end;
                    *end = NUL;
                }
                save_cpo  = p_cpo;
                p_cpo = (char_u *)"";
                regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
                regmatch.rm_ic = FALSE;
                if (end != NULL)
                    *end = save_char;
                p_cpo = save_cpo;
                if (regmatch.regprog == NULL)
                    EMSG2(_(e_invarg2), pat);
                else
                {
                    /*
                     * Save the value of got_int and reset it.  We don't want
                     * a previous interruption cancel matching, only hitting
                     * CTRL-C while matching should abort it.
                     */
                    prev_got_int = got_int;
                    got_int = FALSE;
                    caught = vim_regexec_nl(&regmatch, current_exception->value,
                            (colnr_T)0);
                    got_int |= prev_got_int;
                    vim_free(regmatch.regprog);
                }
            }
        }

        if (caught)
        {
            /* Make this ":catch" clause active and reset did_emsg, got_int,
             * and did_throw.  Put the exception on the caught stack. */
            cstack->cs_flags[idx] |= CSF_ACTIVE | CSF_CAUGHT;
            did_emsg = got_int = did_throw = FALSE;
            catch_exception((except_T *)cstack->cs_exception[idx]);
            /* It's mandatory that the current exception is stored in the cstack
             * so that it can be discarded at the next ":catch", ":finally", or
             * ":endtry" or when the catch clause is left by a ":continue",
             * ":break", ":return", ":finish", error, interrupt, or another
             * exception. */
            if (cstack->cs_exception[cstack->cs_idx] != current_exception)
                EMSG(_(e_internal));
        }
        else
        {
            /*
             * If there is a preceding catch clause and it caught the exception,
             * finish the exception now.  This happens also after errors except
             * when this ":catch" was after the ":finally" or not within
             * a ":try".  Make the try conditional inactive so that the
             * following catch clauses are skipped.  On an error or interrupt
             * after the preceding try block or catch clause was left by
             * a ":continue", ":break", ":return", or ":finish", discard the
             * pending action.
             */
            cleanup_conditionals(cstack, CSF_TRY, TRUE);
        }
    }

    if (end != NULL)
        eap->nextcmd = find_nextcmd(end);
}

/*
 * ":finally"
 */
    void
ex_finally(eap)
    exarg_T     *eap;
{
    int         idx;
    int         skip = FALSE;
    int         pending = CSTP_NONE;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0)
        eap->errmsg = (char_u *)N_("E606: :finally without :try");
    else
    {
        if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY))
        {
            eap->errmsg = get_end_emsg(cstack);
            for (idx = cstack->cs_idx - 1; idx > 0; --idx)
                if (cstack->cs_flags[idx] & CSF_TRY)
                    break;
            /* Make this error pending, so that the commands in the following
             * finally clause can be executed.  This overrules also a pending
             * ":continue", ":break", ":return", or ":finish". */
            pending = CSTP_ERROR;
        }
        else
            idx = cstack->cs_idx;

        if (cstack->cs_flags[idx] & CSF_FINALLY)
        {
            /* Give up for a multiple ":finally" and ignore it. */
            eap->errmsg = (char_u *)N_("E607: multiple :finally");
            return;
        }
        rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
                                                       &cstack->cs_looplevel);

        /*
         * Don't do something when the corresponding try block never got active
         * (because of an inactive surrounding conditional or after an error or
         * interrupt or throw) or for a ":finally" without ":try" or a multiple
         * ":finally".  After every other error (did_emsg or the conditional
         * errors detected above) or after an interrupt (got_int) or an
         * exception (did_throw), the finally clause must be executed.
         */
        skip = !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);

        if (!skip)
        {
            /* When debugging or a breakpoint was encountered, display the
             * debug prompt (if not already done).  The user then knows that the
             * finally clause is executed. */
            if (dbg_check_skipped(eap))
            {
                /* Handle a ">quit" debug command as if an interrupt had
                 * occurred before the ":finally".  That is, discard the
                 * original exception and replace it by an interrupt
                 * exception. */
                (void)do_intthrow(cstack);
            }

            /*
             * If there is a preceding catch clause and it caught the exception,
             * finish the exception now.  This happens also after errors except
             * when this is a multiple ":finally" or one not within a ":try".
             * After an error or interrupt, this also discards a pending
             * ":continue", ":break", ":finish", or ":return" from the preceding
             * try block or catch clause.
             */
            cleanup_conditionals(cstack, CSF_TRY, FALSE);

            /*
             * Make did_emsg, got_int, did_throw pending.  If set, they overrule
             * a pending ":continue", ":break", ":return", or ":finish".  Then
             * we have particularly to discard a pending return value (as done
             * by the call to cleanup_conditionals() above when did_emsg or
             * got_int is set).  The pending values are restored by the
             * ":endtry", except if there is a new error, interrupt, exception,
             * ":continue", ":break", ":return", or ":finish" in the following
             * finally clause.  A missing ":endwhile", ":endfor" or ":endif"
             * detected here is treated as if did_emsg and did_throw had
             * already been set, respectively in case that the error is not
             * converted to an exception, did_throw had already been unset.
             * We must not set did_emsg here since that would suppress the
             * error message.
             */
            if (pending == CSTP_ERROR || did_emsg || got_int || did_throw)
            {
                if (cstack->cs_pending[cstack->cs_idx] == CSTP_RETURN)
                {
                    report_discard_pending(CSTP_RETURN,
                                           cstack->cs_rettv[cstack->cs_idx]);
                    discard_pending_return(cstack->cs_rettv[cstack->cs_idx]);
                }
                if (pending == CSTP_ERROR && !did_emsg)
                    pending |= (THROW_ON_ERROR) ? CSTP_THROW : 0;
                else
                    pending |= did_throw ? CSTP_THROW : 0;
                pending |= did_emsg  ? CSTP_ERROR     : 0;
                pending |= got_int   ? CSTP_INTERRUPT : 0;
                cstack->cs_pending[cstack->cs_idx] = pending;

                /* It's mandatory that the current exception is stored in the
                 * cstack so that it can be rethrown at the ":endtry" or be
                 * discarded if the finally clause is left by a ":continue",
                 * ":break", ":return", ":finish", error, interrupt, or another
                 * exception.  When emsg() is called for a missing ":endif" or
                 * a missing ":endwhile"/":endfor" detected here, the
                 * exception will be discarded. */
                if (did_throw && cstack->cs_exception[cstack->cs_idx]
                                                         != current_exception)
                    EMSG(_(e_internal));
            }

            /*
             * Set CSL_HAD_FINA, so do_cmdline() will reset did_emsg,
             * got_int, and did_throw and make the finally clause active.
             * This will happen after emsg() has been called for a missing
             * ":endif" or a missing ":endwhile"/":endfor" detected here, so
             * that the following finally clause will be executed even then.
             */
            cstack->cs_lflags |= CSL_HAD_FINA;
        }
    }
}

/*
 * ":endtry"
 */
    void
ex_endtry(eap)
    exarg_T     *eap;
{
    int         idx;
    int         skip;
    int         rethrow = FALSE;
    int         pending = CSTP_NONE;
    void        *rettv = NULL;
    struct condstack    *cstack = eap->cstack;

    if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0)
        eap->errmsg = (char_u *)N_("E602: :endtry without :try");
    else
    {
        /*
         * Don't do something after an error, interrupt or throw in the try
         * block, catch clause, or finally clause preceding this ":endtry" or
         * when an error or interrupt occurred after a ":continue", ":break",
         * ":return", or ":finish" in a try block or catch clause preceding this
         * ":endtry" or when the try block never got active (because of an
         * inactive surrounding conditional or after an error or interrupt or
         * throw) or when there is a surrounding conditional and it has been
         * made inactive by a ":continue", ":break", ":return", or ":finish" in
         * the finally clause.  The latter case need not be tested since then
         * anything pending has already been discarded. */
        skip = did_emsg || got_int || did_throw ||
            !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);

        if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY))
        {
            eap->errmsg = get_end_emsg(cstack);
            /* Find the matching ":try" and report what's missing. */
            idx = cstack->cs_idx;
            do
                --idx;
            while (idx > 0 && !(cstack->cs_flags[idx] & CSF_TRY));
            rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
                                                       &cstack->cs_looplevel);
            skip = TRUE;

            /*
             * If an exception is being thrown, discard it to prevent it from
             * being rethrown at the end of this function.  It would be
             * discarded by the error message, anyway.  Resets did_throw.
             * This does not affect the script termination due to the error
             * since "trylevel" is decremented after emsg() has been called.
             */
            if (did_throw)
                discard_current_exception();
        }
        else
        {
            idx = cstack->cs_idx;

            /*
             * If we stopped with the exception currently being thrown at this
             * try conditional since we didn't know that it doesn't have
             * a finally clause, we need to rethrow it after closing the try
             * conditional.
             */
            if (did_throw && (cstack->cs_flags[idx] & CSF_TRUE)
                    && !(cstack->cs_flags[idx] & CSF_FINALLY))
                rethrow = TRUE;
        }

        /* If there was no finally clause, show the user when debugging or
         * a breakpoint was encountered that the end of the try conditional has
         * been reached: display the debug prompt (if not already done).  Do
         * this on normal control flow or when an exception was thrown, but not
         * on an interrupt or error not converted to an exception or when
         * a ":break", ":continue", ":return", or ":finish" is pending.  These
         * actions are carried out immediately.
         */
        if ((rethrow || (!skip
                        && !(cstack->cs_flags[idx] & CSF_FINALLY)
                        && !cstack->cs_pending[idx]))
                && dbg_check_skipped(eap))
        {
            /* Handle a ">quit" debug command as if an interrupt had occurred
             * before the ":endtry".  That is, throw an interrupt exception and
             * set "skip" and "rethrow". */
            if (got_int)
            {
                skip = TRUE;
                (void)do_intthrow(cstack);
                /* The do_intthrow() call may have reset did_throw or
                 * cstack->cs_pending[idx].*/
                rethrow = FALSE;
                if (did_throw && !(cstack->cs_flags[idx] & CSF_FINALLY))
                    rethrow = TRUE;
            }
        }

        /*
         * If a ":return" is pending, we need to resume it after closing the
         * try conditional; remember the return value.  If there was a finally
         * clause making an exception pending, we need to rethrow it.  Make it
         * the exception currently being thrown.
         */
        if (!skip)
        {
            pending = cstack->cs_pending[idx];
            cstack->cs_pending[idx] = CSTP_NONE;
            if (pending == CSTP_RETURN)
                rettv = cstack->cs_rettv[idx];
            else if (pending & CSTP_THROW)
                current_exception = cstack->cs_exception[idx];
        }

        /*
         * Discard anything pending on an error, interrupt, or throw in the
         * finally clause.  If there was no ":finally", discard a pending
         * ":continue", ":break", ":return", or ":finish" if an error or
         * interrupt occurred afterwards, but before the ":endtry" was reached.
         * If an exception was caught by the last of the catch clauses and there
         * was no finally clause, finish the exception now.  This happens also
         * after errors except when this ":endtry" is not within a ":try".
         * Restore "emsg_silent" if it has been reset by this try conditional.
         */
        (void)cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, TRUE);

        --cstack->cs_idx;
        --cstack->cs_trylevel;

        if (!skip)
        {
            report_resume_pending(pending,
                    (pending == CSTP_RETURN) ? rettv :
                    (pending & CSTP_THROW) ? (void *)current_exception : NULL);
            switch (pending)
            {
                case CSTP_NONE:
                    break;

                /* Reactivate a pending ":continue", ":break", ":return",
                 * ":finish" from the try block or a catch clause of this try
                 * conditional.  This is skipped, if there was an error in an
                 * (unskipped) conditional command or an interrupt afterwards
                 * or if the finally clause is present and executed a new error,
                 * interrupt, throw, ":continue", ":break", ":return", or
                 * ":finish". */
                case CSTP_CONTINUE:
                    ex_continue(eap);
                    break;
                case CSTP_BREAK:
                    ex_break(eap);
                    break;
                case CSTP_RETURN:
                    do_return(eap, FALSE, FALSE, rettv);
                    break;
                case CSTP_FINISH:
                    do_finish(eap, FALSE);
                    break;

                /* When the finally clause was entered due to an error,
                 * interrupt or throw (as opposed to a ":continue", ":break",
                 * ":return", or ":finish"), restore the pending values of
                 * did_emsg, got_int, and did_throw.  This is skipped, if there
                 * was a new error, interrupt, throw, ":continue", ":break",
                 * ":return", or ":finish".  in the finally clause. */
                default:
                    if (pending & CSTP_ERROR)
                        did_emsg = TRUE;
                    if (pending & CSTP_INTERRUPT)
                        got_int = TRUE;
                    if (pending & CSTP_THROW)
                        rethrow = TRUE;
                    break;
            }
        }

        if (rethrow)
            /* Rethrow the current exception (within this cstack). */
            do_throw(cstack);
    }
}

/*
 * enter_cleanup() and leave_cleanup()
 *
 * Functions to be called before/after invoking a sequence of autocommands for
 * cleanup for a failed command.  (Failure means here that a call to emsg()
 * has been made, an interrupt occurred, or there is an uncaught exception
 * from a previous autocommand execution of the same command.)
 *
 * Call enter_cleanup() with a pointer to a cleanup_T and pass the same
 * pointer to leave_cleanup().  The cleanup_T structure stores the pending
 * error/interrupt/exception state.
 */

/*
 * This function works a bit like ex_finally() except that there was not
 * actually an extra try block around the part that failed and an error or
 * interrupt has not (yet) been converted to an exception.  This function
 * saves the error/interrupt/ exception state and prepares for the call to
 * do_cmdline() that is going to be made for the cleanup autocommand
 * execution.
 */
    void
enter_cleanup(csp)
    cleanup_T   *csp;
{
    int         pending = CSTP_NONE;

    /*
     * Postpone did_emsg, got_int, did_throw.  The pending values will be
     * restored by leave_cleanup() except if there was an aborting error,
     * interrupt, or uncaught exception after this function ends.
     */
    if (did_emsg || got_int || did_throw || need_rethrow)
    {
        csp->pending = (did_emsg     ? CSTP_ERROR     : 0)
                     | (got_int      ? CSTP_INTERRUPT : 0)
                     | (did_throw    ? CSTP_THROW     : 0)
                     | (need_rethrow ? CSTP_THROW     : 0);

        /* If we are currently throwing an exception (did_throw), save it as
         * well.  On an error not yet converted to an exception, update
         * "force_abort" and reset "cause_abort" (as do_errthrow() would do).
         * This is needed for the do_cmdline() call that is going to be made
         * for autocommand execution.  We need not save *msg_list because
         * there is an extra instance for every call of do_cmdline(), anyway.
         */
        if (did_throw || need_rethrow)
            csp->exception = current_exception;
        else
        {
            csp->exception = NULL;
            if (did_emsg)
            {
                force_abort |= cause_abort;
                cause_abort = FALSE;
            }
        }
        did_emsg = got_int = did_throw = need_rethrow = FALSE;

        /* Report if required by the 'verbose' option or when debugging.  */
        report_make_pending(pending, csp->exception);
    }
    else
    {
        csp->pending = CSTP_NONE;
        csp->exception = NULL;
    }
}

/*
 * See comment above enter_cleanup() for how this function is used.
 *
 * This function is a bit like ex_endtry() except that there was not actually
 * an extra try block around the part that failed and an error or interrupt
 * had not (yet) been converted to an exception when the cleanup autocommand
 * sequence was invoked.
 *
 * This function has to be called with the address of the cleanup_T structure
 * filled by enter_cleanup() as an argument; it restores the error/interrupt/
 * exception state saved by that function - except there was an aborting
 * error, an interrupt or an uncaught exception during execution of the
 * cleanup autocommands.  In the latter case, the saved error/interrupt/
 * exception state is discarded.
 */
    void
leave_cleanup(csp)
    cleanup_T   *csp;
{
    int         pending = csp->pending;

    if (pending == CSTP_NONE)   /* nothing to do */
        return;

    /* If there was an aborting error, an interrupt, or an uncaught exception
     * after the corresponding call to enter_cleanup(), discard what has been
     * made pending by it.  Report this to the user if required by the
     * 'verbose' option or when debugging. */
    if (aborting() || need_rethrow)
    {
        if (pending & CSTP_THROW)
            /* Cancel the pending exception (includes report). */
            discard_exception((except_T *)csp->exception, FALSE);
        else
            report_discard_pending(pending, NULL);

        /* If an error was about to be converted to an exception when
         * enter_cleanup() was called, free the message list. */
        if (msg_list != NULL)
        {
            free_msglist(*msg_list);
            *msg_list = NULL;
        }
    }

    /*
     * If there was no new error, interrupt, or throw between the calls
     * to enter_cleanup() and leave_cleanup(), restore the pending
     * error/interrupt/exception state.
     */
    else
    {
        /*
         * If there was an exception being thrown when enter_cleanup() was
         * called, we need to rethrow it.  Make it the exception currently
         * being thrown.
         */
        if (pending & CSTP_THROW)
            current_exception = csp->exception;

        /*
         * If an error was about to be converted to an exception when
         * enter_cleanup() was called, let "cause_abort" take the part of
         * "force_abort" (as done by cause_errthrow()).
         */
        else if (pending & CSTP_ERROR)
        {
            cause_abort = force_abort;
            force_abort = FALSE;
        }

        /*
         * Restore the pending values of did_emsg, got_int, and did_throw.
         */
        if (pending & CSTP_ERROR)
            did_emsg = TRUE;
        if (pending & CSTP_INTERRUPT)
            got_int = TRUE;
        if (pending & CSTP_THROW)
            need_rethrow = TRUE;    /* did_throw will be set by do_one_cmd() */

        /* Report if required by the 'verbose' option or when debugging. */
        report_resume_pending(pending,
                   (pending & CSTP_THROW) ? (void *)current_exception : NULL);
    }
}


/*
 * Make conditionals inactive and discard what's pending in finally clauses
 * until the conditional type searched for or a try conditional not in its
 * finally clause is reached.  If this is in an active catch clause, finish
 * the caught exception.
 * Return the cstack index where the search stopped.
 * Values used for "searched_cond" are (CSF_WHILE | CSF_FOR) or CSF_TRY or 0,
 * the latter meaning the innermost try conditional not in its finally clause.
 * "inclusive" tells whether the conditional searched for should be made
 * inactive itself (a try conditional not in its finally claused possibly find
 * before is always made inactive).  If "inclusive" is TRUE and
 * "searched_cond" is CSF_TRY|CSF_SILENT, the saved former value of
 * "emsg_silent", if reset when the try conditional finally reached was
 * entered, is restored (unsed by ex_endtry()).  This is normally done only
 * when such a try conditional is left.
 */
    int
cleanup_conditionals(cstack, searched_cond, inclusive)
    struct condstack   *cstack;
    int         searched_cond;
    int         inclusive;
{
    int         idx;
    int         stop = FALSE;

    for (idx = cstack->cs_idx; idx >= 0; --idx)
    {
        if (cstack->cs_flags[idx] & CSF_TRY)
        {
            /*
             * Discard anything pending in a finally clause and continue the
             * search.  There may also be a pending ":continue", ":break",
             * ":return", or ":finish" before the finally clause.  We must not
             * discard it, unless an error or interrupt occurred afterwards.
             */
            if (did_emsg || got_int || (cstack->cs_flags[idx] & CSF_FINALLY))
            {
                switch (cstack->cs_pending[idx])
                {
                    case CSTP_NONE:
                        break;

                    case CSTP_CONTINUE:
                    case CSTP_BREAK:
                    case CSTP_FINISH:
                        report_discard_pending(cstack->cs_pending[idx], NULL);
                        cstack->cs_pending[idx] = CSTP_NONE;
                        break;

                    case CSTP_RETURN:
                        report_discard_pending(CSTP_RETURN,
                                                      cstack->cs_rettv[idx]);
                        discard_pending_return(cstack->cs_rettv[idx]);
                        cstack->cs_pending[idx] = CSTP_NONE;
                        break;

                    default:
                        if (cstack->cs_flags[idx] & CSF_FINALLY)
                        {
                            if (cstack->cs_pending[idx] & CSTP_THROW)
                            {
                                /* Cancel the pending exception.  This is in the
                                 * finally clause, so that the stack of the
                                 * caught exceptions is not involved. */
                                discard_exception((except_T *)
                                        cstack->cs_exception[idx],
                                        FALSE);
                            }
                            else
                                report_discard_pending(cstack->cs_pending[idx],
                                        NULL);
                            cstack->cs_pending[idx] = CSTP_NONE;
                        }
                        break;
                }
            }

            /*
             * Stop at a try conditional not in its finally clause.  If this try
             * conditional is in an active catch clause, finish the caught
             * exception.
             */
            if (!(cstack->cs_flags[idx] & CSF_FINALLY))
            {
                if ((cstack->cs_flags[idx] & CSF_ACTIVE)
                        && (cstack->cs_flags[idx] & CSF_CAUGHT))
                    finish_exception((except_T *)cstack->cs_exception[idx]);
                /* Stop at this try conditional - except the try block never
                 * got active (because of an inactive surrounding conditional
                 * or when the ":try" appeared after an error or interrupt or
                 * throw). */
                if (cstack->cs_flags[idx] & CSF_TRUE)
                {
                    if (searched_cond == 0 && !inclusive)
                        break;
                    stop = TRUE;
                }
            }
        }

        /* Stop on the searched conditional type (even when the surrounding
         * conditional is not active or something has been made pending).
         * If "inclusive" is TRUE and "searched_cond" is CSF_TRY|CSF_SILENT,
         * check first whether "emsg_silent" needs to be restored. */
        if (cstack->cs_flags[idx] & searched_cond)
        {
            if (!inclusive)
                break;
            stop = TRUE;
        }
        cstack->cs_flags[idx] &= ~CSF_ACTIVE;
        if (stop && searched_cond != (CSF_TRY | CSF_SILENT))
            break;

        /*
         * When leaving a try conditional that reset "emsg_silent" on its
         * entry after saving the original value, restore that value here and
         * free the memory used to store it.
         */
        if ((cstack->cs_flags[idx] & CSF_TRY)
                && (cstack->cs_flags[idx] & CSF_SILENT))
        {
            eslist_T    *elem;

            elem = cstack->cs_emsg_silent_list;
            cstack->cs_emsg_silent_list = elem->next;
            emsg_silent = elem->saved_emsg_silent;
            vim_free(elem);
            cstack->cs_flags[idx] &= ~CSF_SILENT;
        }
        if (stop)
            break;
    }
    return idx;
}

/*
 * Return an appropriate error message for a missing endwhile/endfor/endif.
 */
   static char_u *
get_end_emsg(cstack)
    struct condstack    *cstack;
{
    if (cstack->cs_flags[cstack->cs_idx] & CSF_WHILE)
        return e_endwhile;
    if (cstack->cs_flags[cstack->cs_idx] & CSF_FOR)
        return e_endfor;
    return e_endif;
}


/*
 * Rewind conditionals until index "idx" is reached.  "cond_type" and
 * "cond_level" specify a conditional type and the address of a level variable
 * which is to be decremented with each skipped conditional of the specified
 * type.
 * Also free "for info" structures where needed.
 */
    void
rewind_conditionals(cstack, idx, cond_type, cond_level)
    struct condstack   *cstack;
    int         idx;
    int         cond_type;
    int         *cond_level;
{
    while (cstack->cs_idx > idx)
    {
        if (cstack->cs_flags[cstack->cs_idx] & cond_type)
            --*cond_level;
        if (cstack->cs_flags[cstack->cs_idx] & CSF_FOR)
            free_for_info(cstack->cs_forinfo[cstack->cs_idx]);
        --cstack->cs_idx;
    }
}

/*
 * ":endfunction" when not after a ":function"
 */
/*ARGSUSED*/
    void
ex_endfunction(eap)
    exarg_T     *eap;
{
    EMSG(_("E193: :endfunction not inside a function"));
}

/*
 * Return TRUE if the string "p" looks like a ":while" or ":for" command.
 */
    int
has_loop_cmd(p)
    char_u      *p;
{
    p = skipwhite(p);
    while (*p == ':')
        p = skipwhite(p + 1);
    if ((p[0] == 'w' && p[1] == 'h')
            || (p[0] == 'f' && p[1] == 'o' && p[2] == 'r'))
        return TRUE;
    return FALSE;
}

#endif /* FEAT_EVAL */