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Message-Id: <199907052245.AAA07812@moolenaar.net>
To: Johannes Zellner <johannes@zellner.org>
Cc: vim development <vim-dev@vim.org>
Subject: patch 5.4n.5 (was: CursorHold & normal)
In-Reply-To: <Pine.LNX.4.10.9907051733440.29130-100000@krispc6.physik.uni-karlsruhe.de>
From: Bram Moolenaar <Bram@moolenaar.net>
Date: Tue, 06 Jul 1999 00:45:42 +0200
Sender: Bram@moolenaar.net
Content-type: text
Status: U


Johannes Zellner wrote:

> autocmd! CursorHold * normal j
> 
> and vim will hang, at least untill you type an error. Just a note.
> As I had my fingers in CursorHold I might take a look into this evening.

Interesting problem.  The CursorHold event is triggered while waiting for a
character, somewhere down from vgetc().  It then executes the ":normal"
command, which puts "j" in the input buffer and calls normal_cmd() to execute
it.  normal_cmd() then calls vgetc() to get the command character, but since
vgetc() can't work recursively, this is redirected to get_keystroke().  Thus
the "j" in the input buffer is never consumed...

This is too tricky to fix now.  This would probably require returning a
Cursor-hold key code from the input function and handling it at a higher
level.  I don't want to do that now.  Let's just forbid the use of ":normal"
here.  The real solution can be done later (hopefully in a generic way, event
handling has become a bit messy...).


Patch 5.4n.5
Problem:    When using ":normal" from a CursorHold autocommand Vim hangs.  The
            autocommand is executed down from vgetc().  Calling vgetc()
            recursively to execute the command doesn't work then.
Solution:   Forbid the use of ":normal" when vgetc_busy is set.  Give an error
            message when this happens.
Files:      src/ex_docmd.c, runtime/doc/autocmd.txt


*** ../vim-5.4n/src/ex_docmd.c	Sun Jul  4 20:35:46 1999
--- src/ex_docmd.c	Mon Jul  5 22:11:18 1999
***************
*** 6961,6966 ****
--- 6961,6973 ----
  	EMSG("Recursive use of :normal too deep");
  	return;
      }
+     /* Using ":normal" from a CursorHold autocommand event doesn't work,
+      * because vgetc() can't be used recursively. */
+     if (vgetc_busy)
+     {
+ 	EMSG("Cannot use :normal from event handler");
+ 	return;
+     }
      ++depth;
      msg_scroll = FALSE;	    /* no msg scrolling in Normal mode */
      restart_edit = 0;	    /* don't go to Insert mode */
*** ../vim-5.4n/runtime/doc/autocmd.txt	Sun Jul  4 20:36:25 1999
--- runtime/doc/autocmd.txt	Mon Jul  5 22:14:42 1999
***************
*** 1,4 ****
! *autocmd.txt*   For Vim version 5.4n.  Last change: 1999 Jul 03
  
  
  		  VIM REFERENCE MANUAL    by Bram Moolenaar
--- 1,4 ----
! *autocmd.txt*   For Vim version 5.4n.  Last change: 1999 Jul 05
  
  
  		  VIM REFERENCE MANUAL    by Bram Moolenaar
***************
*** 257,266 ****
  				until the user has pressed a key (i.e. doesn't
  				fire every 'updatetime' ms if you leave Vim to
  				make some coffee. :)  See |CursorHold-example|
! 				for previewing tags.  Note: In the future
! 				there will probably be another option to set
! 				the time.  {only on Amiga, Unix, Win32, MSDOS
! 				and all GUI versions}
  							*BufEnter*
  BufEnter			After entering a buffer.  Useful for setting
  				options for a file type.  Also executed when
--- 257,269 ----
  				until the user has pressed a key (i.e. doesn't
  				fire every 'updatetime' ms if you leave Vim to
  				make some coffee. :)  See |CursorHold-example|
! 				for previewing tags.
! 				Note: Interactive commands and ":normal"
! 				cannot be used for this event.
! 				Note: In the future there will probably be
! 				another option to set the time.
! 				{only on Amiga, Unix, Win32, MSDOS and all GUI
! 				versions}
  							*BufEnter*
  BufEnter			After entering a buffer.  Useful for setting
  				options for a file type.  Also executed when

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