Vista - TabExpansion for... command history. And issues...

TabExpansion for... command history. And issues...

I use very long command history, my profile imports previously exported
commands and I finish interactive PowerShell sessions by a wrapper of 'exit'
which exports commands. As a result I keep more than a thousand commands and
quite often I effectively reuse very old of them. Right, I do need a solution
for easy and convenient command search/extraction.

Windows console command history tools (F7, F8) are very primitive and,
worse, they work only on commands of the current session.

Sure, I composed a function which searches the history for a given pattern
and displays matched commands. But after that I have to take a mouse, select,
copy and paste a command, leave a mouse and press enter... The solution is
still not good, especially I hate a mouse in this operation (there is also a
keyboard only way but it is even more ugly).

Finally I have got an idea that it would be quite natural and convenient to
use TabExpansion for that. OK, it is easy: I created my own function
TabExpansion which is a copy of built-in one (Get-Content
function:TabExpansion), slightly extended it and added to my profile.

The idea:

PS> '<pattern>&[tab]
PS> <pattern without spaces>&[tab]

where <pattern> is a standard wildcard pattern (* is always appended to the
end internally). I use the ampersand indicator to avoid conflicts with
expansion of file system paths (they don't contain &) and most of the other
tab expansion cases (correct me if I miss something serious).

Examples:

PS> &[tab]
- just all commands

PS> get&[tab]
- commands starting with 'get'

PS> '*| group&[tab]
- commands containing '| group'

The code below should be inserted next line after "switch -regex ($lastWord)":

----- 8< -----

# Handle command history
# E.g. '<pattern>&[tab] or <pattern>&[tab]
'(.*)&$' {
$pattern = $matches[1] + '*'
$history = Get-History -Count $MaximumHistoryCount | % {
if ($_.CommandLine -like $pattern) {
$_.CommandLine
}
}
for($i = $history.Count; $i-- {
$history[$i]
}
break
}

----- 8< -----

This works *almost* perfectly. This is *almost* what I need so much. Why
almost?

Commands usually contain spaces. It turned out that tab expansion guts treat
such cases like this (note extra ' and &):

Case 1:
PS> '<pattern>&[tab]
Expanded:
PS> '<command>'

Case 2:
PS> <pattern>&[tab]
Expanded:
PS> & '<command>'

I do understand that I am trying to use a tool for what it is not designed.
As for the case 1 I even understand what PowerShell does. To be honest I have
no idea what PowerShell does in the case 2. Could anybody tell or better give
an example when it is used effectively?

This solution is still attractive to me even with all these oddities. Yes, I
remove unwanted ' and & manually every time and still think this way is quite
effective. The question is: do I have a chance to change this unwanted
results of tab expansion? Or at least to fool tab expansion somehow?

P.S. In fact I use not a built-in TabExpansion but a function from
TabExpansion.ps1
http://www.codeplex.com/SourceContro...tName=PsObject. Take a look, it's cool.

P.S. Quite dirty trick how to heal the mentioned problems is below. I do not
like this, but one can find this technique useful for something else.

The trick also uses TabExpansion but actually does nothing for it; instead
it sends few keystrokes to the current console window...

'Input':

PS> '<command>'^[tab]
PS> & '<command>'^[tab]

'Result':

PS> <command>

The code below should be inserted as one more switch case in TabExpansion
switch body:


----- 8< -----

# 'Heal' command lines: '<command>' or & '<command>'
'(.*)\^$' {
if ($line -like "& '*^" -or $line -like "'*^") {
& {
trap {
[void][Reflection.Assembly]::LoadWithPartialName(
'System.Windows.Forms')
continue
}
[void][System.Windows.Forms.SendKeys]
}
if ($line -like "& '*^") {
[System.Windows.Forms.SendKeys]::SendWait(
'{BS}{BS}{HOME}{DEL}{DEL}{DEL}{END}')
}
else {
[System.Windows.Forms.SendKeys]::SendWait(
'{BS}{BS}{HOME}{DEL}{END}')
}
}
break
}

----- 8< -----

--
Thanks,
Roman

One more tab expansion issue (not related to my approach for command history).

As I mentioned, in some cases when the function TabExpansion returns a
string with spaces it is expanded as:

PS> 'string with spaces'

or

PS> & 'string with spaces'

In both cases PowerShell just adds single quotes around a string and *does
not* care of single quotes inside a string at all. This behaviour looks
questionable in any case.

--
Thanks,
Roman

Roman Kuzmin wrote:
> TabExpansion for... command history. And issues...
>
> I use very long command history, my profile imports previously exported
> commands and I finish interactive PowerShell sessions by a wrapper of 'exit'
> which exports commands. As a result I keep more than a thousand commands and
> quite often I effectively reuse very old of them. Right, I do need a solution
> for easy and convenient command search/extraction.

I know what you mean...

Sorry I don't have an answer for the tab expansion questions. What I
did, though, was create a "last" command that searches the command
history backwards for a given regular expression.

It works something like:

% last pack
Run 'zipper pack c:\foo\bar2.zpr' (Y/N)? n
Run 'zipper pack c:\foo\bar.zpr' (Y/N)? y
....

It's still not nearly as good as bash's Ctrl-R history searching, but
with a good regular expression it finds the one I want pretty quickly.
Then you don't need to copy and paste with the mouse.

"Adam Milazzo" wrote:
> % last pack
> Run 'zipper pack c:\foo\bar2.zpr' (Y/N)? n
> Run 'zipper pack c:\foo\bar.zpr' (Y/N)? y
> ....

I was thinking of a similar solution. But approximately in 50% cases first I
have to modify a command a bit. That is why I am looking for a solution
giving me a command text just in the command line ready for both execution or
modification. TabExpansion of a pattern is exactly what I need. Unfortunately
it is not perfect due to added extra symbols & and '. It would be great to
know how to control results of tab expansion more precisely if it is possible.

--
Thanks,
Roman

At least it would be interesting to know, is it OK that tab expansion changes
my data? Perhaps it is not at all. If I can customize data for tab expansion,
then I guess, PowerShell must just display them as they are, it is my duty to
take care of spaces or whatever else in what I return back.

TabExpansion is a good ready to use tool to extend currently quite limited
UI according to a user needs. That's a pity that it behaves like it does now.
And I still do not see reasons for that.

--
Thanks,
Roman

In RC2, the strings returned by the TabExpansion function are no longer
automatically quoted so you may be able to do what you want.

-bruce
--
Bruce Payette [MSFT]
Windows PowerShell Technical Lead
Microsoft Corporation
This posting is provided "AS IS" with no warranties, and confers no rights.


"Roman Kuzmin" <RomanKuzmin@discussions.microsoft.com> wrote in message
news:776FCBFD-A950-4BCE-9478-202CEE7DA3CE@microsoft.com...
> "Adam Milazzo" wrote:
>> % last pack
>> Run 'zipper pack c:\foo\bar2.zpr' (Y/N)? n
>> Run 'zipper pack c:\foo\bar.zpr' (Y/N)? y
>> ....
>
> I was thinking of a similar solution. But approximately in 50% cases first
> I
> have to modify a command a bit. That is why I am looking for a solution
> giving me a command text just in the command line ready for both execution
> or
> modification. TabExpansion of a pattern is exactly what I need.
> Unfortunately
> it is not perfect due to added extra symbols & and '. It would be great to
> know how to control results of tab expansion more precisely if it is
> possible.
>
> --
> Thanks,
> Roman
>

"Bruce Payette [MSFT]" wrote:
> In RC2, the strings returned by the TabExpansion function are no longer
> automatically quoted so you may be able to do what you want.

What can I say? It's just great!! I do have plans for using TabExpansion
very intensively for my needs (actually I use it already but with weird
workaround).

--
Thanks,
Roman