Command not found handler for non-searched commands?

Command not found handler for non-searched commands?

[Benjamin R. Haskell]

I use autocd quite a bit.  And often the first thing I want to do when 
starting a new project is to create a directory and cd into it.  I tried 
creating the following command_not_found_handler:

command_not_found_handler () {
   local dir create
   echo HEREIAM >&2
   (( $# == 1 )) || return 1
   [[ $1 == */* ]] || return 1
   dir=$1
   read -q "create?Create $dir [y/N]? " || return 1
   mkdir -p $dir || return 1
   cd $dir
}

But, it doesn't get called when I need it:

## when I don't need it:
$ fake-command-here
HEREIAM
zsh: command not found: fake-command-here

## when I do need it:
$ ~/tmp/one-off-project
zsh: no such file or directory: /home/bhaskell/tmp/one-off-project

I see from the description of how commands are found that it won't get 
called when there's a slash in the command.  Is there a way to force it? 
Otherwise, is there another, easy way to accomplish my goal?

-- 
Best,
Ben

Re: Command not found handler for non-searched commands?

[Benjamin R. Haskell]

On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:

> I use autocd quite a bit.  And often the first thing I want to do when 
> starting a new project is to create a directory and cd into it.  I tried 
> creating the following command_not_found_handler:
>

Okay.  Different tack, different problem:

preexec {
   __last_command=$1
   # ... etc.
}

trap '
   local dir= create=
   set -- ${=__last_command}
   (( $# == 1 )) || return 1
   [[ $1 == */* ]] || return 1
   dir=$1
   read -q "create?Create $dir [y/N]? " || return 1
   mkdir -p $dir || return 1
   cd $dir
' ZERR

Now $dir ends up containing '~/tmp/one-off-project', with the '~' 
unexpanded.  Seeing as how the directory doesn't yet exist, I can't just 
glob it.  Is there a function to do just named-directory expansion?

-- 
Best,
Ben

Re: Command not found handler for non-searched commands?

[Benjamin R. Haskell]

On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:

> On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:
>
>> I use autocd quite a bit.  And often the first thing I want to do when 
>> starting a new project is to create a directory and cd into it.  I tried 
>> creating the following command_not_found_handler:
>> 
>
> Okay.  Different tack, different problem:
>
> preexec {
>  __last_command=$1
>  # ... etc.
> }
>
> trap '
>  local dir= create=
>  set -- ${=__last_command}
>  (( $# == 1 )) || return 1
>  [[ $1 == */* ]] || return 1
>  dir=$1
>  read -q "create?Create $dir [y/N]? " || return 1
>  mkdir -p $dir || return 1
>  cd $dir
> ' ZERR
>
> Now $dir ends up containing '~/tmp/one-off-project', with the '~' 
> unexpanded.  Seeing as how the directory doesn't yet exist, I can't 
> just glob it.  Is there a function to do just named-directory 
> expansion?

Answered my own question, kind of...  I found the '~' parameter 
expansion flag.  Still don't 100% understand why pattern expansion 
(terminology?) is different than globbing w.r.t. non-existent files. 
Final solution ended up as the following (Difference is the 'dir=${~1}' 
line):


preexec {
  __last_command=$1
  # ... etc.
}

trap '
  local dir= create=
  set -- ${=__last_command}
  (( $# == 1 )) || return 1
  [[ $1 == */* ]] || return 1
  dir=${~1}
  read -q "create?Create $dir [y/N]? " || return 1
  mkdir -p $dir || return 1
  cd $dir
' ZERR

-- 
Best,
Ben

Re: Command not found handler for non-searched commands?

[Benjamin R. Haskell]

On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:

> On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:
> 
> > I use autocd quite a bit.  And often the first thing I want to do when
> > starting a new project is to create a directory and cd into it.  I tried
> > creating the following command_not_found_handler:
> > 
> 
> Okay.  Different tack, different problem:
> 
> preexec {
>  __last_command=$1
>  # ... etc.
> }
> 
> trap '
>  local dir= create=
>  set -- ${=__last_command}
>  (( $# == 1 )) || return 1
>  [[ $1 == */* ]] || return 1
>  dir=$1
>  read -q "create?Create $dir [y/N]? " || return 1
>  mkdir -p $dir || return 1
>  cd $dir
> ' ZERR
> 
> Now $dir ends up containing '~/tmp/one-off-project', with the '~' unexpanded.
> Seeing as how the directory doesn't yet exist, I can't just glob it.  Is there
> a function to do just named-directory expansion?

Answered my own question, kind of...  I found the '~' parameter expansion flag.
Still don't 100% understand why pattern expansion (terminology?) is different
than globbing w.r.t. non-existent files. Final solution ended up as the
following (Difference is the 'dir=${~1}' line):


preexec {
  __last_command=$1
  # ... etc.
}

trap '
  local dir= create=
  set -- ${=__last_command}
  (( $# == 1 )) || return 1
  [[ $1 == */* ]] || return 1
  dir=${~1}
  read -q "create?Create $dir [y/N]? " || return 1
  mkdir -p $dir || return 1
  cd $dir
' ZERR

-- 
Best,
Ben

Re: Command not found handler for non-searched commands?

[Benjamin R. Haskell]

On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:

> On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:
>
>> On Sun, 29 Apr 2012, Benjamin R. Haskell wrote:
>> 
>> > I use autocd quite a bit.  And often the first thing I want to do 
>> > when starting a new project is to create a directory and cd into 
>> > it.  I tried creating the following command_not_found_handler:
>> > 
>> Okay.  Different tack, different problem:
>> [...]
> Final solution ended up as the following [...]:
>
> preexec {
> __last_command=$1
> # ... etc.
> }
>
> trap '
> local dir= create=
> set -- ${=__last_command}
> (( $# == 1 )) || return 1
> [[ $1 == */* ]] || return 1
> dir=${~1}
> read -q "create?Create $dir [y/N]? " || return 1
> mkdir -p $dir || return 1
> cd $dir
> ' ZERR

Still talking to myself, but in case someone else follows my lead, I 
found fairly quickly that this wreaks havoc on unrelated non-zero 
error codes.  (e.g. `false ; echo yay` does not echo 'yay').

After reading the section from the manual on:

trap '' ZERR
vs.
TRAPZERR () { }

yet again, I realized I shouldn't be calling 'return' explicitly 
(because it returns from the calling context).  So, I'm now at:

preexec {
 	__last_command=$1
 	# ... etc.
}

trap '
 	local dir= choose=
 	set -- ${=__last_command}
 	if (( $# == 1 )) && [[ $1 == */* ]] ; then
 		if read -q "choose?Create $1 [y/N]? " ; then
 			dir=${~1}
 			if mkdir -p $dir ; then
 				cd $dir
 			fi
 		fi
 	fi
' ZERR


This still feels substantially heavier-weight than the 
command_not_found_handler I'd been hoping for.  But, it seems to be 
working.

-- 
Best,
Ben