PATCH: dynamic directory name completion

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

I've been playing around with dynamic directory names for referring to
recently used directories and in the process realised that rather than
having to overload _dynamic_directory_name in order to complete dynamic
directory names it would be much more natural to call the original
function, zsh_directory_name, with a new code letter.  You don't lose
anything at all by this---you can still overload _dynamic_directory_name
if you prefer.

Here's the change with a tested (but rather less useful than the code
I'm aiming at) example.

Index: Completion/Zsh/Context/_dynamic_directory_name
===================================================================
RCS file: /cvsroot/zsh/zsh/Completion/Zsh/Context/_dynamic_directory_name,v
retrieving revision 1.1
diff -p -u -r1.1 _dynamic_directory_name
--- Completion/Zsh/Context/_dynamic_directory_name	29 Sep 2008 17:40:55 -0000	1.1
+++ Completion/Zsh/Context/_dynamic_directory_name	11 Jun 2010 22:12:36 -0000
@@ -1,7 +1,7 @@
 #autoload
 
-# The core libraries don't check for dynamic directory name expansion;
-# this gets called from _subscript.  This is a placeholder for
-# people to overload.
-
-_message 'dynamic directory name: redefine _dynamic_directory_name to use'
+if [[ -n $functions[zsh_directory_name] ]]; then
+  zsh_directory_name c
+else
+  _message 'dynamic directory name: implemented as zsh_directory_name c'
+fi
Index: Doc/Zsh/expn.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/expn.yo,v
retrieving revision 1.115
diff -p -u -r1.115 expn.yo
--- Doc/Zsh/expn.yo	11 Jun 2010 20:08:02 -0000	1.115
+++ Doc/Zsh/expn.yo	11 Jun 2010 22:12:37 -0000
@@ -1451,6 +1451,12 @@ parts of the directory path, as describe
 length matched (16 in the example) is longer than that matched by any
 static name.
 
+The completion system calls `tt(zsh_directory_name c)' in order to
+completion dynamic names for directories.  The code for this should be
+as for any other completion function as described in
+ifnzman(noderef(Completion System))\
+ifzman(zmanref(zshcompsys)).
+
 As a working example, here is a function that expands any dynamic names
 beginning with the string tt(p:) to directories below
 tt(/home/pws/perforce).  In this simple case a static name for the
@@ -1461,16 +1467,28 @@ example(zsh_directory_name+LPAR()RPAR() 
   setopt extendedglob
   local -a match mbegin mend
   if [[ $1 = d ]]; then
+    # turn the directory into a name
     if [[ $2 = (#b)(/home/pws/perforce/)([^/]##)* ]]; then
       typeset -ga reply
       reply=(p:$match[2] $(( ${#match[1]} + ${#match[2]} )) )
     else
       return 1
     fi
-  else
+  elif [[ $1 = n ]]; then
+    # turn the name into a directory
     [[ $2 != (#b)p:(?*) ]] && return 1
     typeset -ga reply
     reply=(/home/pws/perforce/$match[1])
+  elif [[ $1 = c ]]; then
+    # complete names
+    local expl
+    local -a dirs
+    dirs=(/home/pws/perforce/*(/:t))
+    dirs=(p:${^dirs})
+    _wanted dynamic-dirs expl 'dynamic directory' compadd -S\] -a dirs
+    return
+  else
+    return 1
   fi
   return 0
 })

-- 
Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/