Add autoenv, automatic environment setup

Using a hook, automatically detect when `.enter` and `.exit` scripts
and source them when changing the shells current directory.

autoenv/autoenv.plugin.zsh

@@ -11,9 +11,9 @@ _autoenv_entered=()
 _autoenv_enter() {
   local entered=$1
   # If entered has already been sourced, return.
-  (( ${+_autoenv_entered[${_autoenv_entered[(i)$entered]}]} )) && return
+  (( ${+_autoenv_entered[$entered]} )) && return
   # If the enter script is not authorized, return.
-  # TODO: _autoenv_authorized $entered/.enter || return
+  _autoenv_authorized $entered/.enter || return
   # Source the enter script.
   source $entered/.enter
   # Add the entered directory to the global entered array.
@@ -25,11 +25,11 @@ _autoenv_enter() {
 _autoenv_exit() {
   local entered=$1
   # If the exit script is not authorized, return.
-  # TODO: _autoenv_authorized $entered/.exit || return
+  _autoenv_authorized $entered/.exit || return
   # Source the exit script.
   source $entered/.exit
   # Remove the entered directory from the global entered array.
-  _autoenv_entered[${_autoenv_entered[(i)$entered]}]=()
+  _autoenv_entered-=$entered
 }
 
 # Find a directory containing a .enter file by searching up the directory tree
@@ -37,7 +37,7 @@ _autoenv_exit() {
 _autoenv_find_enter() {
   local current=$PWD
   # If an enter script is found in the current directory, return it.
-  [ -f "$current/.enter" ] && echo $current
+  [ -f $current/.enter ] && return $current
   # Loop until an enter script or the root directory is found.
   while true; do
     # Walk up one directory and make the path absolute.
@@ -45,7 +45,7 @@ _autoenv_find_enter() {
     # If the current directory equals the next directory, return.
     [[ $current == $next ]] && return || local current=$next
     # If an enter script is found in the current directory, return it.
-    [ -f $current/.enter ] && echo $current
+    [ -f $current/.enter ] && return $current
   done
 }
 
@@ -54,20 +54,21 @@ _autoenv_find_enter() {
 _autoenv_chpwd() {
   local entered
   # Loop over the entered directory stack.
-  for entered in $_autoenv_entered; do
+  for entered in _autoenv_entered; do
     # If the the current directory was previously entered then exit.
     # TODO: Verify what this condition expression actually does.
     ! [[ $PWD/ == $entered/* ]] && _autoenv_exit $entered
   done
   # Find the nearest enter script directory.
   local enter=`_autoenv_find_enter`
-  # If the enter directory exists, enter it.
-  [ -d "$enter" ] && _autoenv_enter $enter
+  # If the enter file doesn't exist, return.
+  ! [ -f $enter ] $enter && return
+  _autoenv_enter $enter
 }
 
 # Register the autoenv chpwd hook.
 autoload -U add-zsh-hook
-add-zsh-hook chpwd _autoenv_chpwd
+add-zsh-hook _autoenv_chpwd
 
 # Ensure autoenv is activated in the current directory on first load.
 _autoenv_chpwd