Make registry 1.3 package (and possibly others) dynamically loadable in Tcl 8.4

Reverted.  No good reason to partially hack 8.5 features
into (only one patch release of) 8.4.  If you need to support
Tcl 8.4, just don't use [tcl::pkgconfig].  If you're set on
moving to [tcl::pkgconfig], then that's an 8.5 features and 
you're choosing to drop 8.4 support.

3 files changed, 50 insertions, 22 deletions

diff --git a/ChangeLog b/ChangeLog
index de29b61..8ad896e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2012-07-16  Jan Nijtmans  <nijtmans@users.sf.net>
+
+	* library/init.tcl:  Make registry 1.3 package (and possibly others)
+	* tests/init.test:   dynamically loadable in Tcl 8.4.
+
 2012-07-05  Don Porter  <dgp@users.sourceforge.net>
 
 	* unix/tclUnixPipe.c:	[Bug 1189293] Make "<<" binary safe.
diff --git a/library/init.tcl b/library/init.tcl
index f2f85e1..4c4b6db 100644
--- a/library/init.tcl
+++ b/library/init.tcl
@@ -66,7 +66,7 @@ namespace eval tcl {
 	}
     }
 }
-  
+
 # Windows specific end of initialization
 
 if {(![interp issafe]) && $tcl_platform(platform) eq "windows"} {
@@ -187,7 +187,7 @@ proc unknown args {
     # may get modified if caught errors occur below.  The variables will
     # be restored just before re-executing the missing command.
 
-    # Safety check in case something unsets the variables 
+    # Safety check in case something unsets the variables
     # ::errorInfo or ::errorCode.  [Bug 1063707]
     if {![info exists errorCode]} {
 	set errorCode ""
@@ -222,7 +222,7 @@ proc unknown args {
 	    if {$code ==  1} {
 		#
 		# Compute stack trace contribution from the [uplevel].
-		# Note the dependence on how Tcl_AddErrorInfo, etc. 
+		# Note the dependence on how Tcl_AddErrorInfo, etc.
 		# construct the stack trace.
 		#
 		set cinfo $args
@@ -340,7 +340,7 @@ proc unknown args {
 # library file to create the procedure.  Returns 1 if it successfully
 # loaded the procedure, 0 otherwise.
 #
-# Arguments: 
+# Arguments:
 # cmd -			Name of the command to find and load.
 # namespace (optional)  The namespace where the command is being used - must be
 #                       a canonical namespace as returned [namespace current]
@@ -364,7 +364,7 @@ proc auto_load {cmd {namespace {}}} {
 	    #    info commands $name
 	    # Unfortunately, if the name has glob-magic chars in it like *
 	    # or [], it may not match.  For our purposes here, a better
-	    # route is to use 
+	    # route is to use
 	    #    namespace which -command $name
 	    if {[namespace which -command $name] ne ""} {
 		return 1
@@ -395,7 +395,7 @@ proc auto_load {cmd {namespace {}}} {
 # of available commands.  Returns 1 if the index is loaded, and 0 if
 # the index is already loaded and up to date.
 #
-# Arguments: 
+# Arguments:
 # None.
 
 proc auto_load_index {} {
@@ -424,7 +424,7 @@ proc auto_load_index {} {
 		    eval [read $f]
 		} elseif {$id eq "# Tcl autoload index file: each line identifies a Tcl"} {
 		    while {[gets $f line] >= 0} {
-			if {[string index $line 0] eq "#" 
+			if {[string index $line 0] eq "#"
 				|| ([llength $line] != 2)} {
 			    continue
 			}
@@ -484,7 +484,7 @@ proc auto_qualify {cmd namespace} {
 	    return [list [string range $cmd 2 end]]
 	}
     }
-    
+
     # Potentially returning 2 elements to try  :
     # (if the current namespace is not the global one)
 
@@ -542,13 +542,13 @@ proc auto_import {pattern} {
 
 # auto_execok --
 #
-# Returns string that indicates name of program to execute if 
+# Returns string that indicates name of program to execute if
 # name corresponds to a shell builtin or an executable in the
-# Windows search path, or "" otherwise.  Builds an associative 
-# array auto_execs that caches information about previous checks, 
+# Windows search path, or "" otherwise.  Builds an associative
+# array auto_execs that caches information about previous checks,
 # for speed.
 #
-# Arguments: 
+# Arguments:
 # name -			Name of a command.
 
 if {$tcl_platform(platform) eq "windows"} {
@@ -603,7 +603,7 @@ proc auto_execok name {
 
     set path "[file dirname [info nameof]];.;"
     if {[info exists env(WINDIR)]} {
-	set windir $env(WINDIR) 
+	set windir $env(WINDIR)
     }
     if {[info exists windir]} {
 	if {$tcl_platform(os) eq "Windows NT"} {
@@ -668,13 +668,13 @@ proc auto_execok name {
 # This procedure is called by Tcl's core when attempts to call the
 # filesystem's copydirectory function fail.  The semantics of the call
 # are that 'dest' does not yet exist, i.e. dest should become the exact
-# image of src.  If dest does exist, we throw an error.  
-# 
+# image of src.  If dest does exist, we throw an error.
+#
 # Note that making changes to this procedure can change the results
 # of running Tcl's tests.
 #
-# Arguments: 
-# action -              "renaming" or "copying" 
+# Arguments:
+# action -              "renaming" or "copying"
 # src -			source directory
 # dest -		destination directory
 proc tcl::CopyDirectory {action src dest} {
@@ -729,12 +729,12 @@ proc tcl::CopyDirectory {action src dest} {
     # Have to be careful to capture both visible and hidden files.
     # We will also be more generous to the file system and not
     # assume the hidden and non-hidden lists are non-overlapping.
-    # 
+    #
     # On Unix 'hidden' files begin with '.'.  On other platforms
     # or filesystems hidden files may have other interpretations.
     set filelist [concat [glob -nocomplain -directory $src *] \
       [glob -nocomplain -directory $src -types hidden *]]
-    
+
     foreach s [lsort -unique $filelist] {
 	if {([file tail $s] ne ".") && ([file tail $s] ne "..")} {
 	    file copy $s [file join $dest [file tail $s]]
@@ -742,3 +742,23 @@ proc tcl::CopyDirectory {action src dest} {
     }
     return
 }
+
+# ::tcl::pkgconfig --
+#
+# This procedure is undocumented. It is meant to make the dde
+# and registry packages distributed with Tcl 8.6 and the Thread
+# 2.7 package (and possibly others) dynamically loadable in Tcl 8.4.
+#
+# Arguments:
+# action -              "get"
+# key -			"debug" or "threaded"
+proc tcl::pkgconfig {{action {}} {key {}} args} {
+    if {$action eq "get"} {
+	if {$key eq "debug"} {
+	    return [info exists ::tcl_platform(debug)]
+	} elseif {$key eq "threaded"} {
+	    return [info exists ::tcl_platform(threaded)]
+	}
+    }
+    error {invalid command name "::tcl::pkgconfig"}
+}
diff --git a/tests/init.test b/tests/init.test
index 79142c4..c46ba48 100644
--- a/tests/init.test
+++ b/tests/init.test
@@ -117,13 +117,11 @@ test init-2.6 {load setLogCmd from safe:: - stage 1} {
     rename ::safe::setLogCmd {} ; # should not fail
 } {}
 
-test init-2.7 {oad setLogCmd from safe::  - stage 2} {
+test init-2.7 {load setLogCmd from safe::  - stage 2} {
     namespace eval safe setLogCmd 
     rename ::safe::setLogCmd {} ; # should not fail
 } {}
 
-
-
 test init-2.8 {load tcl::HistAdd} -setup {
     auto_reset
     catch {rename ::tcl::HistAdd {}}
@@ -134,6 +132,11 @@ test init-2.8 {load tcl::HistAdd} -setup {
     rename ::tcl::HistAdd {} ; 
 } -result {1 {wrong # args: should be "tcl:::HistAdd command ?exec?"}}
 
+test init-2.9 {undocumented tcl::pkgconfig} -setup {
+} -body {
+    list [catch {::tcl::pkgconfig} error] $error
+    } -cleanup {
+} -result {1 {invalid command name "::tcl::pkgconfig"}}
 
 test init-3.0 {random stuff in the auto_index, should still work} {
     set auto_index(foo:::bar::blah) {