neovim

ex_eval.c (71398B)

---

/// @file ex_eval.c
///
/// Functions for Ex command line for the +eval feature.
#include <assert.h>
#include <inttypes.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>

#include "nvim/ascii_defs.h"
#include "nvim/charset.h"
#include "nvim/debugger.h"
#include "nvim/errors.h"
#include "nvim/eval.h"
#include "nvim/eval/typval.h"
#include "nvim/eval/typval_defs.h"
#include "nvim/eval/userfunc.h"
#include "nvim/eval/vars.h"
#include "nvim/eval_defs.h"
#include "nvim/ex_cmds_defs.h"
#include "nvim/ex_docmd.h"
#include "nvim/ex_eval.h"
#include "nvim/ex_eval_defs.h"
#include "nvim/gettext_defs.h"
#include "nvim/globals.h"
#include "nvim/memory.h"
#include "nvim/message.h"
#include "nvim/option_vars.h"
#include "nvim/regexp.h"
#include "nvim/regexp_defs.h"
#include "nvim/runtime.h"
#include "nvim/runtime_defs.h"
#include "nvim/strings.h"
#include "nvim/vim_defs.h"

#include "ex_eval.c.generated.h"

static const char e_multiple_else[] = N_("E583: Multiple :else");
static const char e_multiple_finally[] = N_("E607: Multiple :finally");

// 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 asynchronously 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.

// Values used for the Vim release.
#define THROW_ON_ERROR true
#define THROW_ON_ERROR_TRUE
#define THROW_ON_INTERRUPT true
#define THROW_ON_INTERRUPT_TRUE

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

static void discard_pending_return(typval_T *p)
{
 tv_free(p);
}

// 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 bool 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. "got_int" is also set by calling interrupt().
bool aborting(void)
{
 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(void)
{
 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.
bool should_abort(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.
bool aborted_in_try(void)
 FUNC_ATTR_PURE
{
 // 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.
bool cause_errthrow(const char *mesg, bool multiline, bool severe, bool *ignore)
 FUNC_ATTR_NONNULL_ALL
{
 msglist_T *elem;

 // 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 == _(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.  Therefore, 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) {
     msglist_T **plist = msg_list;
     while (*plist != NULL) {
       plist = &(*plist)->next;
     }

     elem = xmalloc(sizeof(msglist_T));
     elem->msg = xstrdup(mesg);
     elem->multiline = multiline;
     elem->next = NULL;
     elem->throw_msg = NULL;
     *plist = elem;
     if (plist == msg_list || severe) {
       // Skip the extra "Vim " prefix for message "E458".
       char *tmsg = elem->msg;
       if (strncmp(tmsg, "Vim E", 5) == 0
           && ascii_isdigit(tmsg[5])
           && ascii_isdigit(tmsg[6])
           && ascii_isdigit(tmsg[7])
           && tmsg[8] == ':'
           && tmsg[9] == ' ') {
         (*msg_list)->throw_msg = &tmsg[4];
       } else {
         (*msg_list)->throw_msg = tmsg;
       }
     }

     // Get the source name and lnum now, it may change before
     // reaching do_errthrow().
     elem->sfile = estack_sfile(ESTACK_NONE);
     elem->slnum = SOURCING_LNUM;
   }
   return true;
 }
}

/// Free a "msg_list" and the messages it contains.
static void free_msglist(msglist_T *l)
{
 msglist_T *messages = l;
 while (messages != NULL) {
   msglist_T *next = messages->next;
   xfree(messages->msg);
   xfree(messages->sfile);
   xfree(messages);
   messages = next;
 }
}

/// Free global "*msg_list" and the messages it contains, then set "*msg_list"
/// to NULL.
void free_global_msglist(void)
{
 free_msglist(*msg_list);
 *msg_list = NULL;
}

/// 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_T *cstack, char *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 or,
///          false otherwise.
bool do_intthrow(cstack_T *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);
 }
#ifdef THROW_TEST
}
#endif

 return true;
}

/// Get an exception message that is to be stored in current_exception->value.
char *get_exception_string(void *value, except_type_T type, char *cmdname, bool *should_free)
{
 char *ret;

 if (type == ET_ERROR) {
   char *val;
   *should_free = true;
   char *mesg = ((msglist_T *)value)->throw_msg;
   if (cmdname != NULL && *cmdname != NUL) {
     size_t cmdlen = strlen(cmdname);
     ret = xstrnsave("Vim(", 4 + cmdlen + 2 + strlen(mesg));
     STRCPY(&ret[4], cmdname);
     STRCPY(&ret[4 + cmdlen], "):");
     val = ret + 4 + cmdlen + 2;
   } else {
     ret = xstrnsave("Vim:", 4 + strlen(mesg));
     val = ret + 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 (char *p = mesg;; p++) {
     if (*p == NUL
         || (*p == 'E'
             && ascii_isdigit(p[1])
             && (p[2] == ':'
                 || (ascii_isdigit(p[2])
                     && (p[3] == ':'
                         || (ascii_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;
         snprintf(val + strlen(p), strlen(" (%s)"), " (%s)", &mesg[1]);
         p[-2] = '"';
       }
       break;
     }
   }
 } else {
   *should_free = false;
   ret = value;
 }

 return ret;
}

/// Throw a new exception.  "value" is the exception string for a
/// user or interrupt exception, or points to a message list in case of an
/// error exception.
///
/// @return  FAIL when out of memory or it was tried to throw an illegal user
///          exception.
static int throw_exception(void *value, except_type_T type, char *cmdname)
{
 // 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(value, "Vim", 3) == 0
       && (((char *)value)[3] == NUL || ((char *)value)[3] == ':'
           || ((char *)value)[3] == '(')) {
     emsg(_("E608: Cannot :throw exceptions with 'Vim' prefix"));
     goto fail;
   }
 }

 except_T *excp = xmalloc(sizeof(except_T));

 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 = (msglist_T *)value;
 }

 bool should_free;
 excp->value = get_exception_string(value, type, cmdname, &should_free);
 if (excp->value == NULL && should_free) {
   goto nomem;
 }

 excp->type = type;
 if (type == ET_ERROR && ((msglist_T *)value)->sfile != NULL) {
   msglist_T *entry = (msglist_T *)value;
   excp->throw_name = entry->sfile;
   entry->sfile = NULL;
   excp->throw_lnum = entry->slnum;
 } else {
   excp->throw_name = estack_sfile(ESTACK_NONE);
   if (excp->throw_name == NULL) {
     excp->throw_name = xstrdup("");
   }
   excp->throw_lnum = SOURCING_LNUM;
 }

 excp->stacktrace = stacktrace_create();
 tv_list_ref(excp->stacktrace);

 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(0, _("Exception thrown: %s"), excp->value);
   msg_puts("\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:
 xfree(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(except_T *excp, bool was_finished)
{
 if (current_exception == excp) {
   current_exception = NULL;
 }
 if (excp == NULL) {
   internal_error("discard_exception()");
   return;
 }

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

   char *saved_IObuff = xstrdup(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(0, was_finished ? _("Exception finished: %s") : _("Exception discarded: %s"), excp->value);
   msg_puts("\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();
   }
   xstrlcpy(IObuff, saved_IObuff, IOSIZE);
   xfree(saved_IObuff);
 }
 if (excp->type != ET_INTERRUPT) {
   xfree(excp->value);
 }
 if (excp->type == ET_ERROR) {
   free_msglist(excp->messages);
 }
 xfree(excp->throw_name);
 tv_list_unref(excp->stacktrace);
 xfree(excp);
}

/// Discard the exception currently being thrown.
void discard_current_exception(void)
{
 if (current_exception != NULL) {
   discard_exception(current_exception, false);
 }
 // Note: all globals manipulated here should be saved/restored in
 // try_enter/try_leave.
 did_throw = false;
 need_rethrow = false;
}

/// Put an exception on the caught stack.
static void catch_exception(except_T *excp)
{
 excp->caught = caught_stack;
 caught_stack = excp;
 set_vim_var_string(VV_EXCEPTION, excp->value, -1);
 set_vim_var_list(VV_STACKTRACE, excp->stacktrace);
 if (*excp->throw_name != NUL) {
   if (excp->throw_lnum != 0) {
     vim_snprintf(IObuff, IOSIZE, _("%s, line %" PRId64),
                  excp->throw_name, (int64_t)excp->throw_lnum);
   } else {
     vim_snprintf(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(0, _("Exception caught: %s"), excp->value);
   msg_puts("\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(except_T *excp)
{
 if (excp != caught_stack) {
   internal_error("finish_exception()");
 }
 caught_stack = caught_stack->caught;
 if (caught_stack != NULL) {
   set_vim_var_string(VV_EXCEPTION, caught_stack->value, -1);
   set_vim_var_list(VV_STACKTRACE, caught_stack->stacktrace);
   if (*caught_stack->throw_name != NUL) {
     if (caught_stack->throw_lnum != 0) {
       vim_snprintf(IObuff, IOSIZE,
                    _("%s, line %" PRId64), caught_stack->throw_name,
                    (int64_t)caught_stack->throw_lnum);
     } else {
       vim_snprintf(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);
   set_vim_var_list(VV_STACKTRACE, NULL);
 }

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

/// Save the current exception state in "estate"
void exception_state_save(exception_state_T *estate)
{
 estate->estate_current_exception = current_exception;
 estate->estate_did_throw = did_throw;
 estate->estate_need_rethrow = need_rethrow;
 estate->estate_trylevel = trylevel;
 estate->estate_did_emsg = did_emsg;
}

/// Restore the current exception state from "estate"
void exception_state_restore(exception_state_T *estate)
{
 // Handle any outstanding exceptions before restoring the state
 if (did_throw) {
   handle_did_throw();
 }
 current_exception = estate->estate_current_exception;
 did_throw = estate->estate_did_throw;
 need_rethrow = estate->estate_need_rethrow;
 trylevel = estate->estate_trylevel;
 did_emsg = estate->estate_did_emsg;
}

/// Clear the current exception state
void exception_state_clear(void)
{
 current_exception = NULL;
 did_throw = false;
 need_rethrow = false;
 trylevel = 0;
 did_emsg = 0;
}

// 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(int action, int pending, void *value)
{
 char *mesg;
 char *s;

 assert(value || !(pending & CSTP_THROW));

 switch (action) {
 case RP_MAKE:
   mesg = _("%s made pending");
   break;
 case RP_RESUME:
   mesg = _("%s resumed");
   break;
 // case RP_DISCARD:
 default:
   mesg = _("%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 = get_return_cmd(value);
   break;

 default:
   if (pending & CSTP_THROW) {
     vim_snprintf(IObuff, IOSIZE,
                  mesg, _("Exception"));
     mesg = concat_str(IObuff, ": %s");
     s = ((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");
   }
 }

 int 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(0, mesg, s);
 msg_puts("\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) {
   xfree(s);
 } else if (pending & CSTP_THROW) {
   xfree(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(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.
static void report_resume_pending(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.
static void report_discard_pending(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();
   }
 }
}

/// Handle ":eval".
void ex_eval(exarg_T *eap)
{
 typval_T tv;
 evalarg_T evalarg;

 fill_evalarg_from_eap(&evalarg, eap, eap->skip);

 if (eval0(eap->arg, &tv, eap, &evalarg) == OK) {
   tv_clear(&tv);
 }

 clear_evalarg(&evalarg, eap);
}

/// Handle ":if".
void ex_if(exarg_T *eap)
{
 cstack_T *const cstack = eap->cstack;

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

   bool skip = CHECK_SKIP;

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

   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;
   }
 }
}

/// Handle ":endif".
void ex_endif(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 = _("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)) {
     do_intthrow(eap->cstack);
   }

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

/// Handle ":else" and ":elseif".
void ex_else(exarg_T *eap)
{
 cstack_T *const cstack = eap->cstack;

 bool skip = CHECK_SKIP;

 if (cstack->cs_idx < 0
     || (cstack->cs_flags[cstack->cs_idx]
         & (CSF_WHILE | CSF_FOR | CSF_TRY))) {
   if (eap->cmdidx == CMD_else) {
     eap->errmsg = _("E581: :else without :if");
     return;
   }
   eap->errmsg = _("E582: :elseif without :if");
   skip = true;
 } else if (cstack->cs_flags[cstack->cs_idx] & CSF_ELSE) {
   if (eap->cmdidx == CMD_else) {
     eap->errmsg = _(e_multiple_else);
     return;
   }
   eap->errmsg = _("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) {
   do_intthrow(cstack);
   skip = true;
 }

 if (eap->cmdidx == CMD_elseif) {
   bool result = false;
   bool error;
   // When skipping we ignore most errors, but a missing expression is
   // wrong, perhaps it should have been "else".
   // A double quote here is the start of a string, not a comment.
   if (skip && *eap->arg != '"' && ends_excmd(*eap->arg)) {
     semsg(_(e_invexpr2), eap->arg);
   } else {
     result = eval_to_bool(eap->arg, &error, eap, skip, false);
   }

   // 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(exarg_T *eap)
{
 bool error;
 cstack_T *const cstack = eap->cstack;

 if (cstack->cs_idx == CSTACK_LEN - 1) {
   eap->errmsg = _("E585: :while/:for nesting too deep");
 } else {
   bool result;
   // 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;

   int skip = CHECK_SKIP;
   if (eap->cmdidx == CMD_while) {  // ":while bool-expr"
     result = eval_to_bool(eap->arg, &error, eap, skip, false);
   } else {  // ":for var in list-expr"
     evalarg_T evalarg;
     fill_evalarg_from_eap(&evalarg, eap, skip);
     void *fi;
     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, &evalarg);
       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;
     }
     clear_evalarg(&evalarg, eap);
   }

   // 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;
     }
   }
 }
}

/// Handle ":continue"
void ex_continue(exarg_T *eap)
{
 cstack_T *const cstack = eap->cstack;

 if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0) {
   eap->errmsg = _("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).  Therefore, deactivate all conditionals except the ":while"
   // itself (if reached).
   int idx = cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, false);
   assert(idx >= 0);
   if (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);
   }
 }
}

/// Handle ":break"
void ex_break(exarg_T *eap)
{
 cstack_T *const cstack = eap->cstack;

 if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0) {
   eap->errmsg = _("E587: :break without :while or :for");
 } else {
   // Deactivate 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".
   int 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);
   }
 }
}

/// Handle ":endwhile" and ":endfor"
void ex_endwhile(exarg_T *eap)
{
 cstack_T *const cstack = eap->cstack;
 const char *err;
 int csf;

 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 {
   int 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 = _("E732: Using :endfor with :while");
     } else if (fl & CSF_FOR) {
       eap->errmsg = _("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.
     int idx;
     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.
     cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, false);
     rewind_conditionals(cstack, idx, CSF_TRY, &cstack->cs_trylevel);
   } else if (cstack->cs_flags[cstack->cs_idx] & CSF_TRUE
              && !(cstack->cs_flags[cstack->cs_idx] & CSF_ACTIVE)
              && dbg_check_skipped(eap)) {
     // 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.
     do_intthrow(cstack);
   }

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

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

 if (*arg != NUL && *arg != '|' && *arg != '\n') {
   value = eval_to_string_skip(arg, eap, 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) {
     xfree(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_T *cstack)
{
 bool inactivate_try = false;

 // Cleanup and deactivate up to the next surrounding try conditional that
 // is not in its finally clause.  Normally, do not deactivate 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,
 // deactivate 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.

#ifndef THROW_ON_ERROR_TRUE
 if (did_emsg && !THROW_ON_ERROR) {
   inactivate_try = true;
   did_emsg = false;
 }
#endif
#ifndef THROW_ON_INTERRUPT_TRUE
 if (got_int && !THROW_ON_INTERRUPT) {
   inactivate_try = true;
   got_int = false;
 }
#endif
 int 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;
 }

 did_throw = true;
}

/// Handle ":try"
void ex_try(exarg_T *eap)
{
 cstack_T *const cstack = eap->cstack;

 if (cstack->cs_idx == CSTACK_LEN - 1) {
   eap->errmsg = _("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;

   int skip = CHECK_SKIP;

   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 = xmalloc(sizeof(*elem));
       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;
     }
   }
 }
}

/// Handle ":catch /{pattern}/" and ":catch"
void ex_catch(exarg_T *eap)
{
 int idx = 0;
 bool give_up = false;
 bool skip = false;
 char *end;
 char *save_cpo;
 regmatch_T regmatch;
 cstack_T *const cstack = eap->cstack;
 char *pat;

 if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0) {
   eap->errmsg = _("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 = _("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 = ".*";
   end = NULL;
   eap->nextcmd = find_nextcmd(eap->arg);
 } else {
   pat = eap->arg + 1;
   end = skip_regexp_err(pat, *eap->arg, true);
   if (end == NULL) {
     give_up = true;
   }
 }

 if (!give_up) {
   bool caught = false;
   // 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))) {
       semsg(_(e_trailing_arg), end);
       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)) {
       char save_char = 0;
       // 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 = empty_string_option;
       // Disable error messages, it will make current exception
       // invalid
       emsg_off++;
       regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
       emsg_off--;
       regmatch.rm_ic = false;
       if (end != NULL) {
         *end = save_char;
       }
       p_cpo = save_cpo;
       if (regmatch.regprog == NULL) {
         semsg(_(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.

         int prev_got_int = got_int;
         got_int = false;
         caught = vim_regexec_nl(&regmatch, current_exception->value, 0);
         got_int |= prev_got_int;
         vim_regfree(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) {
       internal_error("ex_catch()");
     }
   } 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);
 }
}

/// Handle ":finally"
void ex_finally(exarg_T *eap)
{
 int idx;
 int pending = CSTP_NONE;
 cstack_T *const cstack = eap->cstack;

 for (idx = cstack->cs_idx; idx >= 0; idx--) {
   if (cstack->cs_flags[idx] & CSF_TRY) {
     break;
   }
 }
 if (cstack->cs_trylevel <= 0 || idx < 0) {
   eap->errmsg = _("E606: :finally without :try");
   return;
 }

 if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
   eap->errmsg = get_end_emsg(cstack);
   // 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;
 }

 if (cstack->cs_flags[idx] & CSF_FINALLY) {
   // Give up for a multiple ":finally" and ignore it.
   eap->errmsg = _(e_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.
 int 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.
     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;
     assert(pending >= CHAR_MIN && pending <= CHAR_MAX);
     cstack->cs_pending[cstack->cs_idx] = (char)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) {
       internal_error("ex_finally()");
     }
   }

   // 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;
 }
}

/// Handle ":endtry"
void ex_endtry(exarg_T *eap)
{
 int idx;
 bool rethrow = false;
 char pending = CSTP_NONE;
 void *rettv = NULL;
 cstack_T *const cstack = eap->cstack;

 for (idx = cstack->cs_idx; idx >= 0; idx--) {
   if (cstack->cs_flags[idx] & CSF_TRY) {
     break;
   }
 }
 if (cstack->cs_trylevel <= 0 || idx < 0) {
   eap->errmsg = _("E602: :endtry without :try");
   return;
 }

 // 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.
 bool 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.
   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();
   }

   // report eap->errmsg, also when there already was an error
   did_emsg = false;
 } 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;
     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.
 cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, true);

 if (cstack->cs_idx >= 0 && (cstack->cs_flags[cstack->cs_idx] & CSF_TRY)) {
   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(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;
     current_exception = NULL;
   } 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;
 }
}

/// 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.
///
/// See comment above enter_cleanup() for how this function is used.
///
/// 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(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(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_global_msglist();
   }
 } else {
   // 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.

   // 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;
   } else if (pending & CSTP_ERROR) {
     // 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()).
     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.
///
///
/// @param searched_cond  Possible values are (CSF_WHILE | CSF_FOR) or CSF_TRY or 0,
///                       the latter meaning the innermost try conditional not
///                       in its finally clause.
/// @param inclusive      tells whether the conditional searched for should be made
///                       inactive itself (a try conditional not in its finally
///                       clause 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 (used by ex_endtry()).  This is normally
/// done only when such a try conditional is left.
///
/// @return  the cstack index where the search stopped.
int cleanup_conditionals(cstack_T *cstack, int searched_cond, int inclusive)
{
 int idx;
 bool 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) && cstack->cs_exception[idx] != NULL) {
             // 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) && !(cstack->cs_flags[idx] & CSF_FINISHED)) {
         finish_exception((except_T *)cstack->cs_exception[idx]);
         cstack->cs_flags[idx] |= CSF_FINISHED;
       }
       // 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;
     xfree(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 *get_end_emsg(cstack_T *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_T *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--;
 }
}

/// Handle ":endfunction" when not after a ":function"
void ex_endfunction(exarg_T *eap)
{
 semsg(_(e_str_not_inside_function), ":endfunction");
}

/// @return  true if the string "p" looks like a ":while" or ":for" command.
bool has_loop_cmd(char *p)
{
 // skip modifiers, white space and ':'
 while (true) {
   while (*p == ' ' || *p == '\t' || *p == ':') {
     p++;
   }
   int len = modifier_len(p);
   if (len == 0) {
     break;
   }
   p += len;
 }
 if ((p[0] == 'w' && p[1] == 'h')
     || (p[0] == 'f' && p[1] == 'o' && p[2] == 'r')) {
   return true;
 }
 return false;
}