Index: modules/virtchannel_base/facade.tcl
==================================================================
--- modules/virtchannel_base/facade.tcl
+++ modules/virtchannel_base/facade.tcl
@@ -30,11 +30,11 @@
 # @@ Meta End
 
 # # ## ### ##### ######## #############
 ## TODO document the special options of the facade
 ## TODO log integration.
-## TODO document that facada takes ownership of the channel.
+## TODO document that facade takes ownership of the channel.
 
 package require Tcl 8.5
 package require TclOO
 package require logger
 package require tcl::chan::core
@@ -204,10 +204,22 @@
 	    -user $user
 
 	log::debug {[self] cgetall $myself -> $result}
 	return $result
     }
+
+    method seek {myself offset base} {
+	set value [::chan seek $chan $offset $base]
+	log::debug {[self] seek $myself $option $base -> $value}
+	return $value
+    }
+
+    method truncate {myself newloc} {
+	::chan truncate $chan $newloc
+	log::debug {[self] truncate $myself $newloc}
+	return
+    }
 
     # # ## ### ##### ######## #############
 
     # Internals. Methods. Event generation.
     method Readable {myself} {
@@ -228,7 +240,7 @@
 
     # # ## ### ##### ######## #############
 }
 
 # # ## ### ##### ######## #############
-package provide tcl::chan::facade 1.0.1
+package provide tcl::chan::facade 1.0.2
 return

Index: modules/virtchannel_base/halfpipe.tcl
==================================================================
--- modules/virtchannel_base/halfpipe.tcl
+++ modules/virtchannel_base/halfpipe.tcl
@@ -146,11 +146,11 @@
     # is to split the buffer into two. An append-only receive buffer
     # (`write`) for incoming data, and a `read` buffer with the
     # pointer. When the current read buffer is entirely consumed the
     # current receive buffer becomes the new read buffer and a new
     # empty receive buffer is started.
-    
+
     # # ## ### ##### ######## #############
 
     constructor {args} {
 	array set options {
 	    -write-command {}

Index: modules/virtchannel_base/memchan.tcl
==================================================================
--- modules/virtchannel_base/memchan.tcl
+++ modules/virtchannel_base/memchan.tcl
@@ -57,11 +57,11 @@
 	my allow write
 	my Events
 	next {*}$args
     }
 
-    variable content at 
+    variable content at
 
     method read {c n} {
 	# First determine the location of the last byte to read,
 	# relative to the current location, and limited by the maximum
 	# location we are allowed to access per the size of the
@@ -151,10 +151,28 @@
 	set at $newloc
 
 	my Events
 	return $at
     }
+
+    method truncate {c newloc} {
+	# Check if the new location is beyond the range given by the
+	# content.
+
+	set max [string length $content]
+	if {$newloc < 0} {
+	    return -code error "Cannot truncate before the start of the channel"
+	} elseif {$newloc > $max} {
+	    # We can truncate beyond the end of the current contents, add
+	    # a block of zeros.
+	    #puts XXX.PAD.[expr {$newloc - $max}]
+	    append content [binary format @[expr {$newloc - $max}]]
+	} elseif {$newloc < $max} {
+	    set content [string range $content 0 $newloc-1]
+	}
+	return
+    }
 
     method Events {} {
 	# Always readable -- Even if the seek location is at the end
 	# (or beyond).  In that case the readable events are fired
 	# endlessly until the eof indicated by the seek location is
@@ -163,7 +181,7 @@
 	my allow read
     }
 }
 
 # # ## ### ##### ######## #############
-package provide tcl::chan::memchan 1.0.4
+package provide tcl::chan::memchan 1.0.5
 return

Index: modules/virtchannel_base/pkgIndex.tcl
==================================================================
--- modules/virtchannel_base/pkgIndex.tcl
+++ modules/virtchannel_base/pkgIndex.tcl
@@ -1,17 +1,17 @@
 if {![package vsatisfies [package provide Tcl] 8.5]} {return}
 
 package ifneeded tcl::chan::cat 1.0.3      [list source [file join $dir cat.tcl]]
-package ifneeded tcl::chan::facade 1.0.1   [list source [file join $dir facade.tcl]]
+package ifneeded tcl::chan::facade 1.0.2   [list source [file join $dir facade.tcl]]
 package ifneeded tcl::chan::fifo 1         [list source [file join $dir fifo.tcl]]
 package ifneeded tcl::chan::fifo2 1        [list source [file join $dir fifo2.tcl]]
 package ifneeded tcl::chan::halfpipe 1.0.1 [list source [file join $dir halfpipe.tcl]]
-package ifneeded tcl::chan::memchan 1.0.4  [list source [file join $dir memchan.tcl]]
+package ifneeded tcl::chan::memchan 1.0.5  [list source [file join $dir memchan.tcl]]
 package ifneeded tcl::chan::null 1         [list source [file join $dir null.tcl]]
 package ifneeded tcl::chan::nullzero 1     [list source [file join $dir nullzero.tcl]]
 package ifneeded tcl::chan::random 1       [list source [file join $dir random.tcl]]
 package ifneeded tcl::chan::std 1.0.1      [list source [file join $dir std.tcl]]
 package ifneeded tcl::chan::string 1.0.3   [list source [file join $dir string.tcl]]
 package ifneeded tcl::chan::textwindow 1   [list source [file join $dir textwindow.tcl]]
-package ifneeded tcl::chan::variable 1.0.4 [list source [file join $dir variable.tcl]]
+package ifneeded tcl::chan::variable 1.0.5 [list source [file join $dir variable.tcl]]
 package ifneeded tcl::chan::zero 1         [list source [file join $dir zero.tcl]]
 package ifneeded tcl::randomseed 1         [list source [file join $dir randseed.tcl]]

Index: modules/virtchannel_base/string.tcl
==================================================================
--- modules/virtchannel_base/string.tcl
+++ modules/virtchannel_base/string.tcl
@@ -49,11 +49,11 @@
     method initialize {args} {
 	my Events
 	next {*}$args
     }
 
-    variable content at 
+    variable content at
 
     method read {c n} {
 
 	# First determine the location of the last byte to read,
 	# relative to the current location, and limited by the maximum

Index: modules/virtchannel_base/variable.tcl
==================================================================
--- modules/virtchannel_base/variable.tcl
+++ modules/virtchannel_base/variable.tcl
@@ -58,11 +58,11 @@
 	my allow write
 	my Events
 	next {*}$args
     }
 
-    variable varname at 
+    variable varname at
 
     method read {c n} {
 	# Bring connected variable for content into scope.
 
 	upvar #0 $varname content
@@ -163,10 +163,32 @@
 	set at $newloc
 
 	my Events
 	return $at
     }
+
+    method truncate {c newloc} {
+	# Bring connected variable for content into scope.
+
+	upvar #0 $varname content
+
+	# Check if the new location is beyond the range given by the
+	# content.
+
+	set max [string length $content]
+	if {$newloc < 0} {
+	    return -code error "Cannot truncate before the start of the channel"
+	} elseif {$newloc > $max} {
+	    # We can truncate beyond the end of the current contents, add
+	    # a block of zeros.
+	    #puts XXX.PAD.[expr {$newloc - $max}]
+	    append content [binary format @[expr {$newloc - $max}]]
+	} elseif {$newloc < $max} {
+	    set content [string range $content 0 $newloc-1]
+	}
+	return
+    }
 
     method Events {} {
 	# Always readable -- Even if the seek location is at the end
 	# (or beyond).  In that case the readable events are fired
 	# endlessly until the eof indicated by the seek location is
@@ -175,7 +197,7 @@
 	my allow read
     }
 }
 
 # # ## ### ##### ######## #############
-package provide tcl::chan::variable 1.0.4
+package provide tcl::chan::variable 1.0.5
 return

Index: modules/virtchannel_core/core.tcl
==================================================================
--- modules/virtchannel_core/core.tcl
+++ modules/virtchannel_core/core.tcl
@@ -43,11 +43,11 @@
 
 	set channel $thechannel
 	set supported {}
 	foreach m {
 	    initialize finalize watch read write seek configure cget
-	    cgetall blocking
+	    cgetall blocking truncate
 	} {
 	    if {$m in $methods} {
 		lappend supported $m
 	    }
 	}

Index: modules/virtchannel_core/events.tcl
==================================================================
--- modules/virtchannel_core/events.tcl
+++ modules/virtchannel_core/events.tcl
@@ -86,11 +86,11 @@
 
     # # ## ### ##### ######## #############
 
     # Event System State - Timer driven
 
-    variable timer allowed requested posting delay    
+    variable timer allowed requested posting delay
 
     # channel   = The channel to post events to - provided by superclass
     # timer     = Timer controlling the posting.
     # allowed   = Set of events allowed to post.
     # requested = Set of events requested by core.

Index: modules/virtchannel_transform/rot.tcl
==================================================================
--- modules/virtchannel_transform/rot.tcl
+++ modules/virtchannel_transform/rot.tcl
@@ -80,16 +80,14 @@
 		set n [binary format c \
 			   [expr { (($dx - 97 + $key) % 26) + 97 }]]
 	    } else {
 		set n $d
 	    }
-
 	    append result $n
-		
 	}
 	return $result
     }
 }
 
 # # ## ### ##### ######## #############
 package provide tcl::transform::rot 1
 return

