PRE_EXEC?

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#1
Can the special PRE_EXEC alias prevent the execution of the current command (conditionally, of course)?

Again I was thinking of Steve's wanting to handle the loss of the current directory gracefully. This alias does it, but uses a plugin.
Code:
v:\> alias pre_exec
if not isdir %_cwd ( cdd v:\ & genbreak )
With that, if the network was disconnected and the current directory invalid, I see for example
Code:
\\lucky\v$> dir
TCC: (Sys) The specified network name is no longer available.
^C
v:\>
The error message is nice; the "^C" not so nice. I was wondering if it could be done with only built-in tools.
 
#3
PRE_EXEC is not executed until the next command is entered; PRE_INPUT is.
But what about the case the TCC instance is not in active use (may even be minimized or not the current TCMD tab)when the CWD becomes inaccessible?
 
#4
PRE_EXEC is not executed until the next command is entered; PRE_INPUT is.
But what about the case the TCC instance is not in active use (may even be minimized or not the current TCMD tab)when the CWD becomes inaccessible?
I suppose it won't matter until you activate it and try to do something with it.

I did manage (almost) instantaneous notification and automatic fallback to another directory with a plugin.
Code:
v:\> cwdcheck /?
CWDCHECK [1 (on) | 0 (off) | fallback_dir (sticky, changeable, implies 1)]
- with no args, status
It polls in a thread. With a polling interval of 2 seconds, it took 51 minutes before I could detect an increase in TCC's CPU time, and then, the increase was about 1/10 sec (and I cannot definitely attribute all of that increase to CWDCHECK). But I still am uneasy about the whole idea ... using any resources on something that happens once in a blue moon (and for many/most users, never).
 
#5
If one of the systems on your LAN is a laptop, it walks away easily without notifying the other systems in advance. Another frequent situation is a removable (real or virtual) drive on another system mapped to a local drive letter.
BTW, I have no issue with using a plug-in for this task - TCC is a large and wonderful toolbox, but it does not need to have all the tools in the world. This kind of extension is exactly what plug-ins are intended for.
 
#6
If one of the systems on your LAN is a laptop, it walks away easily without notifying the other systems in advance. Another frequent situation is a removable (real or virtual) drive on another system mapped to a local drive letter.
BTW, I have no issue with using a plug-in for this task - TCC is a large and wonderful toolbox, but it does not need to have all the tools in the world. This kind of extension is exactly what plug-ins are intended for.
It's in a private version of my little-touted 4THREADS plugin. I'll post a version here if you want to try it. But I must ask ... do you want it to generate Ctrl-C when it finds the CWD invalid and automatically changes to a fallback directory? I would suppose "Yes". That has the nice effect of causing a new prompt to appear (if you're at the command line) and the break could be handled before a batch file went on to some other error.
 
#11
I would appreciate it.
Do you still have the old one? The only one I found that seemed complete had the following help screen. Can you tell me if that's it? And I even found an obvious bug in that one ... if you asked for %WW_EVENT, it had CREATE and DESTROY reversed!
Code:
WATCHWIN [/C|/D] id  command  [class_regex  [caption_regex]]
 
/C - CREATE only; /D - DESTROY only; these affect all watches and
can only be set with the first watch
 
Default regex: "."; quote args with spaces; \" = literal quote
 
These variables exist for the duration of "command":
 
        WW_EVENT (CREATE/DESTROY), WW_ID, WW_TIME, WW_HANDLE
 
        with CREATE also WW_PID, WW_CAPTION, WW_CLASS, WW_MODULE
 
WATCHWIN /L(ist) [id_regex]
 
WATCHWIN /K(ill) [id_regex]