Merge core-8-6-branch. This removes the work currently being done in "sebres-8-6-clock-speedup-cr1" branch, but that will be merged again as soon as the work is done.

All other changes in "trunk" since then (e.g. the INST_STR_CONCAT1 performance improvement, and the removal of SunOS-4) are retained.

2 files changed, 2693 insertions, 283 deletions

diff --git a/library/clock.tcl b/library/clock.tcl
index 471deff..8e4b657 100644
--- a/library/clock.tcl
+++ b/library/clock.tcl
@@ -10,7 +10,6 @@
 #----------------------------------------------------------------------
 #
 # Copyright (c) 2004,2005,2006,2007 by Kevin B. Kenny
-# Copyright (c) 2015 by Sergey G. Brester aka sebres.
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
@@ -288,12 +287,6 @@ proc ::tcl::clock::Initialize {} {
 
     variable FEB_28	       58
 
-    # Default configuration
-
-    configure -default-locale  [mclocale]
-    #configure -year-century    2000 \
-    #          -century-switch  38
-
     # Translation table to map Windows TZI onto cities, so that the Olson
     # rules can apply.  In some cases the mapping is ambiguous, so it's wise
     # to specify $::env(TCL_TZ) rather than simply depending on the system
@@ -390,6 +383,152 @@ proc ::tcl::clock::Initialize {} {
 	{46800 0 3600 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0}   :Pacific/Tongatapu
     }]
 
+    # Groups of fields that specify the date, priorities, and code bursts that
+    # determine Julian Day Number given those groups.  The code in [clock
+    # scan] will choose the highest priority (lowest numbered) set of fields
+    # that determines the date.
+
+    variable DateParseActions {
+
+	{ seconds } 0 {}
+
+	{ julianDay } 1 {}
+
+	{ era century yearOfCentury month dayOfMonth } 2 {
+	    dict set date year [expr { 100 * [dict get $date century]
+				       + [dict get $date yearOfCentury] }]
+	    set date [GetJulianDayFromEraYearMonthDay $date[set date {}] \
+			  $changeover]
+	}
+	{ era century yearOfCentury dayOfYear } 2 {
+	    dict set date year [expr { 100 * [dict get $date century]
+				       + [dict get $date yearOfCentury] }]
+	    set date [GetJulianDayFromEraYearDay $date[set date {}] \
+			  $changeover]
+	}
+
+	{ century yearOfCentury month dayOfMonth } 3 {
+	    dict set date era CE
+	    dict set date year [expr { 100 * [dict get $date century]
+				       + [dict get $date yearOfCentury] }]
+	    set date [GetJulianDayFromEraYearMonthDay $date[set date {}] \
+			  $changeover]
+	}
+	{ century yearOfCentury dayOfYear } 3 {
+	    dict set date era CE
+	    dict set date year [expr { 100 * [dict get $date century]
+				       + [dict get $date yearOfCentury] }]
+	    set date [GetJulianDayFromEraYearDay $date[set date {}] \
+			  $changeover]
+	}
+	{ iso8601Century iso8601YearOfCentury iso8601Week dayOfWeek } 3 {
+	    dict set date era CE
+	    dict set date iso8601Year \
+		[expr { 100 * [dict get $date iso8601Century]
+			+ [dict get $date iso8601YearOfCentury] }]
+	    set date [GetJulianDayFromEraYearWeekDay $date[set date {}] \
+			 $changeover]
+	}
+
+	{ yearOfCentury month dayOfMonth } 4 {
+	    set date [InterpretTwoDigitYear $date[set date {}] $baseTime]
+	    dict set date era CE
+	    set date [GetJulianDayFromEraYearMonthDay $date[set date {}] \
+			  $changeover]
+	}
+	{ yearOfCentury dayOfYear } 4 {
+	    set date [InterpretTwoDigitYear $date[set date {}] $baseTime]
+	    dict set date era CE
+	    set date [GetJulianDayFromEraYearDay $date[set date {}] \
+			  $changeover]
+	}
+	{ iso8601YearOfCentury iso8601Week dayOfWeek } 4 {
+	    set date [InterpretTwoDigitYear \
+			  $date[set date {}] $baseTime \
+			  iso8601YearOfCentury iso8601Year]
+	    dict set date era CE
+	    set date [GetJulianDayFromEraYearWeekDay $date[set date {}] \
+			 $changeover]
+	}
+
+	{ month dayOfMonth } 5 {
+	    set date [AssignBaseYear $date[set date {}] \
+			  $baseTime $timeZone $changeover]
+	    set date [GetJulianDayFromEraYearMonthDay $date[set date {}] \
+			  $changeover]
+	}
+	{ dayOfYear } 5 {
+	    set date [AssignBaseYear $date[set date {}] \
+			  $baseTime $timeZone $changeover]
+	    set date [GetJulianDayFromEraYearDay $date[set date {}] \
+			 $changeover]
+	}
+	{ iso8601Week dayOfWeek } 5 {
+	    set date [AssignBaseIso8601Year $date[set date {}] \
+			  $baseTime $timeZone $changeover]
+	    set date [GetJulianDayFromEraYearWeekDay $date[set date {}] \
+			 $changeover]
+	}
+
+	{ dayOfMonth } 6 {
+	    set date [AssignBaseMonth $date[set date {}] \
+			  $baseTime $timeZone $changeover]
+	    set date [GetJulianDayFromEraYearMonthDay $date[set date {}] \
+			  $changeover]
+	}
+
+	{ dayOfWeek } 7 {
+	    set date [AssignBaseWeek $date[set date {}] \
+			  $baseTime $timeZone $changeover]
+	    set date [GetJulianDayFromEraYearWeekDay $date[set date {}] \
+			 $changeover]
+	}
+
+	{} 8 {
+	    set date [AssignBaseJulianDay $date[set date {}] \
+			  $baseTime $timeZone $changeover]
+	}
+    }
+
+    # Groups of fields that specify time of day, priorities, and code that
+    # processes them
+
+    variable TimeParseActions {
+
+	seconds 1 {}
+
+	{ hourAMPM minute second amPmIndicator } 2 {
+	    dict set date secondOfDay [InterpretHMSP $date]
+	}
+	{ hour minute second } 2 {
+	    dict set date secondOfDay [InterpretHMS $date]
+	}
+
+	{ hourAMPM minute amPmIndicator } 3 {
+	    dict set date second 0
+	    dict set date secondOfDay [InterpretHMSP $date]
+	}
+	{ hour minute } 3 {
+	    dict set date second 0
+	    dict set date secondOfDay [InterpretHMS $date]
+	}
+
+	{ hourAMPM amPmIndicator } 4 {
+	    dict set date minute 0
+	    dict set date second 0
+	    dict set date secondOfDay [InterpretHMSP $date]
+	}
+	{ hour } 4 {
+	    dict set date minute 0
+	    dict set date second 0
+	    dict set date secondOfDay [InterpretHMS $date]
+	}
+
+	{ } 5 {
+	    dict set date secondOfDay 0
+	}
+    }
+
     # Legacy time zones, used primarily for parsing RFC822 dates.
 
     variable LegacyTimeZone [dict create \
@@ -484,17 +623,17 @@ proc ::tcl::clock::Initialize {} {
 
     # Caches
 
-    variable LocaleFormats \
-			[dict create];	# Dictionary with localized formats
-
-    variable LocaleNumeralCache \
-			[dict create];	# Dictionary whose keys are locale
+    variable LocaleNumeralCache {};	# Dictionary whose keys are locale
 					# names and whose values are pairs
 					# comprising regexes matching numerals
 					# in the given locales and dictionaries
 					# mapping the numerals to their numeric
 					# values.
-    variable TimeZoneBad [dict create]; # Dictionary whose keys are time zone
+    # variable CachedSystemTimeZone;    # If 'CachedSystemTimeZone' exists,
+					# it contains the value of the
+					# system time zone, as determined from
+					# the environment.
+    variable TimeZoneBad {};	        # Dictionary whose keys are time zone
     					# names and whose values are 1 if
 					# the time zone is unknown and 0
     					# if it is known.
@@ -506,147 +645,1644 @@ proc ::tcl::clock::Initialize {} {
     variable FormatProc;		# Array mapping format group
 					# and locale to the name of a procedure
 					# that renders the given format
-
-    variable mcLocales	 [dict create];	# Dictionary with loaded locales
-    variable mcMergedCat [dict create];	# Dictionary with merged locale catalogs
 }
 ::tcl::clock::Initialize
 
 #----------------------------------------------------------------------
+#
+# clock format --
+#
+#	Formats a count of seconds since the Posix Epoch as a time of day.
+#
+# The 'clock format' command formats times of day for output.  Refer to the
+# user documentation to see what it does.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::format { args } {
+
+    variable FormatProc
+    variable TZData
+
+    lassign [ParseFormatArgs {*}$args] format locale timezone
+    set locale [string tolower $locale]
+    set clockval [lindex $args 0]
+
+    # Get the data for time changes in the given zone
+
+    if {$timezone eq ""} {
+	set timezone [GetSystemTimeZone]
+    }
+    if {![info exists TZData($timezone)]} {
+	if {[catch {SetupTimeZone $timezone} retval opts]} {
+	    dict unset opts -errorinfo
+	    return -options $opts $retval
+	}
+    }
 
-# mcget --
+    # Build a procedure to format the result. Cache the built procedure's name
+    # in the 'FormatProc' array to avoid losing its internal representation,
+    # which contains the name resolution.
+
+    set procName formatproc'$format'$locale
+    set procName [namespace current]::[string map {: {\:} \\ {\\}} $procName]
+    if {[info exists FormatProc($procName)]} {
+	set procName $FormatProc($procName)
+    } else {
+	set FormatProc($procName) \
+	    [ParseClockFormatFormat $procName $format $locale]
+    }
+
+    return [$procName $clockval $timezone]
+
+}
+
+#----------------------------------------------------------------------
 #
-#	Return the merged translation catalog for the ::tcl::clock namespace
-#	Searching of catalog is similar to "msgcat::mc".
+# ParseClockFormatFormat --
 #
-#	Contrary to "msgcat::mc" may additionally load a package catalog
-#	on demand.
+#	Builds and caches a procedure that formats a time value.
 #
-# Arguments:
-#	loc	The locale used for translation.
+# Parameters:
+#	format -- Format string to use
+#	locale -- Locale in which the format string is to be interpreted
 #
 # Results:
-#	Returns the dictionary object as whole catalog of the package/locale.
-#
-proc mcget {loc} {
-    variable mcMergedCat
-    switch -- $loc system {
-	set loc [GetSystemLocale]
-    } current {
-	set loc [mclocale]
-    }
-    if {$loc eq {C}} {
-	set loclist [msgcat::PackagePreferences ::tcl::clock]
-	set loc [lindex $loclist 0]
-    } else {
-    	set loc [string tolower $loc]
+#	Returns the name of the newly-built procedure.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::ParseClockFormatFormat {procName format locale} {
+
+    if {[namespace which $procName] ne {}} {
+	return $procName
     }
 
-    # try to retrieve now if already available:
-    if {[dict exists $mcMergedCat $loc]} {
-	set mrgcat [dict get $mcMergedCat $loc]
-	return [dict smartref $mrgcat]
+    # Map away the locale-dependent composite format groups
+
+    EnterLocale $locale
+
+    # Change locale if a fresh locale has been given on the command line.
+
+    try {
+	return [ParseClockFormatFormat2 $format $locale $procName]
+    } trap CLOCK {result opts} {
+	dict unset opts -errorinfo
+	return -options $opts $result
     }
+}
 
-    # get locales list for given locale (de_de -> {de_de de {}})
-    variable mcLocales
-    if {[dict exists $mcLocales $loc]} {
-	set loclist [dict get $mcLocales $loc]
-    } else {
-	# save current locale:
-	set prevloc [mclocale]
-	# lazy load catalog on demand (set it will load the catalog)
-	mcpackagelocale set $loc
-	set loclist [msgcat::GetPreferences $loc]
-	dict set $mcLocales $loc $loclist
-	# restore:
-        if {$prevloc ne $loc} {
-	   mcpackagelocale set $prevloc
-	}
-    }
-    # get whole catalog:
-    mcMerge $loclist
+proc ::tcl::clock::ParseClockFormatFormat2 {format locale procName} {
+    set didLocaleEra 0
+    set didLocaleNumerals 0
+    set preFormatCode \
+	[string map [list @GREGORIAN_CHANGE_DATE@ \
+				       [mc GREGORIAN_CHANGE_DATE]] \
+	     {
+		 variable TZData
+		 set date [GetDateFields $clockval \
+			       $TZData($timezone) \
+			       @GREGORIAN_CHANGE_DATE@]
+	     }]
+    set formatString {}
+    set substituents {}
+    set state {}
+
+    set format [LocalizeFormat $locale $format]
+
+    foreach char [split $format {}] {
+	switch -exact -- $state {
+	    {} {
+		if { [string equal % $char] } {
+		    set state percent
+		} else {
+		    append formatString $char
+		}
+	    }
+	    percent {			# Character following a '%' character
+		set state {}
+		switch -exact -- $char {
+		    % {			# A literal character, '%'
+			append formatString %%
+		    }
+		    a {			# Day of week, abbreviated
+			append formatString %s
+			append substituents \
+			    [string map \
+				 [list @DAYS_OF_WEEK_ABBREV@ \
+				      [list [mc DAYS_OF_WEEK_ABBREV]]] \
+				 { [lindex @DAYS_OF_WEEK_ABBREV@ \
+					[expr {[dict get $date dayOfWeek] \
+						   % 7}]]}]
+		    }
+		    A {			# Day of week, spelt out.
+			append formatString %s
+			append substituents \
+			    [string map \
+				 [list @DAYS_OF_WEEK_FULL@ \
+				      [list [mc DAYS_OF_WEEK_FULL]]] \
+				 { [lindex @DAYS_OF_WEEK_FULL@ \
+					[expr {[dict get $date dayOfWeek] \
+						   % 7}]]}]
+		    }
+		    b - h {		# Name of month, abbreviated.
+			append formatString %s
+			append substituents \
+			    [string map \
+				 [list @MONTHS_ABBREV@ \
+				      [list [mc MONTHS_ABBREV]]] \
+				 { [lindex @MONTHS_ABBREV@ \
+					[expr {[dict get $date month]-1}]]}]
+		    }
+		    B {			# Name of month, spelt out
+			append formatString %s
+			append substituents \
+			    [string map \
+				 [list @MONTHS_FULL@ \
+				      [list [mc MONTHS_FULL]]] \
+				 { [lindex @MONTHS_FULL@ \
+					[expr {[dict get $date month]-1}]]}]
+		    }
+		    C {			# Century number
+			append formatString %02d
+			append substituents \
+			    { [expr {[dict get $date year] / 100}]}
+		    }
+		    d {			# Day of month, with leading zero
+			append formatString %02d
+			append substituents { [dict get $date dayOfMonth]}
+		    }
+		    e {			# Day of month, without leading zero
+			append formatString %2d
+			append substituents { [dict get $date dayOfMonth]}
+		    }
+		    E {			# Format group in a locale-dependent
+					# alternative era
+			set state percentE
+			if {!$didLocaleEra} {
+			    append preFormatCode \
+				[string map \
+				     [list @LOCALE_ERAS@ \
+					  [list [mc LOCALE_ERAS]]] \
+				     {
+					 set date [GetLocaleEra \
+						       $date[set date {}] \
+						       @LOCALE_ERAS@]}] \n
+			    set didLocaleEra 1
+			}
+			if {!$didLocaleNumerals} {
+			    append preFormatCode \
+				[list set localeNumerals \
+				     [mc LOCALE_NUMERALS]] \n
+			    set didLocaleNumerals 1
+			}
+		    }
+		    g {			# Two-digit year relative to ISO8601
+					# week number
+			append formatString %02d
+			append substituents \
+			    { [expr { [dict get $date iso8601Year] % 100 }]}
+		    }
+		    G {			# Four-digit year relative to ISO8601
+					# week number
+			append formatString %02d
+			append substituents { [dict get $date iso8601Year]}
+		    }
+		    H {			# Hour in the 24-hour day, leading zero
+			append formatString %02d
+			append substituents \
+			    { [expr { [dict get $date localSeconds] \
+					  / 3600 % 24}]}
+		    }
+		    I {			# Hour AM/PM, with leading zero
+			append formatString %02d
+			append substituents \
+			    { [expr { ( ( ( [dict get $date localSeconds] \
+					    % 86400 ) \
+					  + 86400 \
+					  - 3600 ) \
+					/ 3600 ) \
+				      % 12 + 1 }] }
+		    }
+		    j {			# Day of year (001-366)
+			append formatString %03d
+			append substituents { [dict get $date dayOfYear]}
+		    }
+		    J {			# Julian Day Number
+			append formatString %07ld
+			append substituents { [dict get $date julianDay]}
+		    }
+		    k {			# Hour (0-23), no leading zero
+			append formatString %2d
+			append substituents \
+			    { [expr { [dict get $date localSeconds]
+				      / 3600
+				      % 24 }]}
+		    }
+		    l {			# Hour (12-11), no leading zero
+			append formatString %2d
+			append substituents \
+			    { [expr { ( ( ( [dict get $date localSeconds]
+					   % 86400 )
+					 + 86400
+					 - 3600 )
+				       / 3600 )
+				     % 12 + 1 }]}
+		    }
+		    m {			# Month number, leading zero
+			append formatString %02d
+			append substituents { [dict get $date month]}
+		    }
+		    M {			# Minute of the hour, leading zero
+			append formatString %02d
+			append substituents \
+			    { [expr { [dict get $date localSeconds]
+				      / 60
+				      % 60 }]}
+		    }
+		    n {			# A literal newline
+			append formatString \n
+		    }
+		    N {			# Month number, no leading zero
+			append formatString %2d
+			append substituents { [dict get $date month]}
+		    }
+		    O {			# A format group in the locale's
+					# alternative numerals
+			set state percentO
+			if {!$didLocaleNumerals} {
+			    append preFormatCode \
+				[list set localeNumerals \
+				     [mc LOCALE_NUMERALS]] \n
+			    set didLocaleNumerals 1
+			}
+		    }
+		    p {			# Localized 'AM' or 'PM' indicator
+					# converted to uppercase
+			append formatString %s
+			append preFormatCode \
+			    [list set AM [string toupper [mc AM]]] \n \
+			    [list set PM [string toupper [mc PM]]] \n
+			append substituents \
+			    { [expr {(([dict get $date localSeconds]
+				       % 86400) < 43200) ?
+				     $AM : $PM}]}
+		    }
+		    P {			# Localized 'AM' or 'PM' indicator
+			append formatString %s
+			append preFormatCode \
+			    [list set am [mc AM]] \n \
+			    [list set pm [mc PM]] \n
+			append substituents \
+			    { [expr {(([dict get $date localSeconds]
+				       % 86400) < 43200) ?
+				     $am : $pm}]}
+
+		    }
+		    Q {			# Hi, Jeff!
+			append formatString %s
+			append substituents { [FormatStarDate $date]}
+		    }
+		    s {			# Seconds from the Posix Epoch
+			append formatString %s
+			append substituents { [dict get $date seconds]}
+		    }
+		    S {			# Second of the minute, with
+			# leading zero
+			append formatString %02d
+			append substituents \
+			    { [expr { [dict get $date localSeconds]
+				      % 60 }]}
+		    }
+		    t {			# A literal tab character
+			append formatString \t
+		    }
+		    u {			# Day of the week (1-Monday, 7-Sunday)
+			append formatString %1d
+			append substituents { [dict get $date dayOfWeek]}
+		    }
+		    U {			# Week of the year (00-53). The
+					# first Sunday of the year is the
+					# first day of week 01
+			append formatString %02d
+			append preFormatCode {
+			    set dow [dict get $date dayOfWeek]
+			    if { $dow == 7 } {
+				set dow 0
+			    }
+			    incr dow
+			    set UweekNumber \
+				[expr { ( [dict get $date dayOfYear]
+					  - $dow + 7 )
+					/ 7 }]
+			}
+			append substituents { $UweekNumber}
+		    }
+		    V {			# The ISO8601 week number
+			append formatString %02d
+			append substituents { [dict get $date iso8601Week]}
+		    }
+		    w {			# Day of the week (0-Sunday,
+					# 6-Saturday)
+			append formatString %1d
+			append substituents \
+			    { [expr { [dict get $date dayOfWeek] % 7 }]}
+		    }
+		    W {			# Week of the year (00-53). The first
+					# Monday of the year is the first day
+					# of week 01.
+			append preFormatCode {
+			    set WweekNumber \
+				[expr { ( [dict get $date dayOfYear]
+					  - [dict get $date dayOfWeek]
+					  + 7 )
+					/ 7 }]
+			}
+			append formatString %02d
+			append substituents { $WweekNumber}
+		    }
+		    y {			# The two-digit year of the century
+			append formatString %02d
+			append substituents \
+			    { [expr { [dict get $date year] % 100 }]}
+		    }
+		    Y {			# The four-digit year
+			append formatString %04d
+			append substituents { [dict get $date year]}
+		    }
+		    z {			# The time zone as hours and minutes
+					# east (+) or west (-) of Greenwich
+			append formatString %s
+			append substituents { [FormatNumericTimeZone \
+						   [dict get $date tzOffset]]}
+		    }
+		    Z {			# The name of the time zone
+			append formatString %s
+			append substituents { [dict get $date tzName]}
+		    }
+		    % {			# A literal percent character
+			append formatString %%
+		    }
+		    default {		# An unknown escape sequence
+			append formatString %% $char
+		    }
+		}
+	    }
+	    percentE {			# Character following %E
+		set state {}
+		switch -exact -- $char {
+		    E {
+			append formatString %s
+			append substituents { } \
+			    [string map \
+				 [list @BCE@ [list [mc BCE]] \
+				      @CE@ [list [mc CE]]] \
+				      {[dict get {BCE @BCE@ CE @CE@} \
+					    [dict get $date era]]}]
+		    }
+		    C {			# Locale-dependent era
+			append formatString %s
+			append substituents { [dict get $date localeEra]}
+		    }
+		    y {			# Locale-dependent year of the era
+			append preFormatCode {
+			    set y [dict get $date localeYear]
+			    if { $y >= 0 && $y < 100 } {
+				set Eyear [lindex $localeNumerals $y]
+			    } else {
+				set Eyear $y
+			    }
+			}
+			append formatString %s
+			append substituents { $Eyear}
+		    }
+		    default {		# Unknown %E format group
+			append formatString %%E $char
+		    }
+		}
+	    }
+	    percentO {			# Character following %O
+		set state {}
+		switch -exact -- $char {
+		    d - e {		# Day of the month in alternative
+			# numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [dict get $date dayOfMonth]]}
+		    }
+		    H - k {		# Hour of the day in alternative
+					# numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [expr { [dict get $date localSeconds]
+					   / 3600
+					   % 24 }]]}
+		    }
+		    I - l {		# Hour (12-11) AM/PM in alternative
+					# numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [expr { ( ( ( [dict get $date localSeconds]
+						 % 86400 )
+					       + 86400
+					       - 3600 )
+					     / 3600 )
+					   % 12 + 1 }]]}
+		    }
+		    m {			# Month number in alternative numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals [dict get $date month]]}
+		    }
+		    M {			# Minute of the hour in alternative
+					# numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [expr { [dict get $date localSeconds]
+					   / 60
+					   % 60 }]]}
+		    }
+		    S {			# Second of the minute in alternative
+					# numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [expr { [dict get $date localSeconds]
+					   % 60 }]]}
+		    }
+		    u {			# Day of the week (Monday=1,Sunday=7)
+					# in alternative numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [dict get $date dayOfWeek]]}
+			}
+		    w {			# Day of the week (Sunday=0,Saturday=6)
+					# in alternative numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [expr { [dict get $date dayOfWeek] % 7 }]]}
+		    }
+		    y {			# Year of the century in alternative
+					# numerals
+			append formatString %s
+			append substituents \
+			    { [lindex $localeNumerals \
+				   [expr { [dict get $date year] % 100 }]]}
+		    }
+		    default {	# Unknown format group
+			append formatString %%O $char
+		    }
+		}
+	    }
+	}
+    }
+
+    # Clean up any improperly terminated groups
+
+    switch -exact -- $state {
+	percent {
+	    append formatString %%
+	}
+	percentE {
+	    append retval %%E
+	}
+	percentO {
+	    append retval %%O
+	}
+    }
+
+    proc $procName {clockval timezone} "
+        $preFormatCode
+        return \[::format [list $formatString] $substituents\]
+    "
+
+    #    puts [list $procName [info args $procName] [info body $procName]]
+
+    return $procName
+}
+
+#----------------------------------------------------------------------
+#
+# clock scan --
+#
+#	Inputs a count of seconds since the Posix Epoch as a time of day.
+#
+# The 'clock format' command scans times of day on input.  Refer to the user
+# documentation to see what it does.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::scan { args } {
+
+    set format {}
+
+    # Check the count of args
+
+    if { [llength $args] < 1 || [llength $args] % 2 != 1 } {
+	set cmdName "clock scan"
+	return -code error \
+	    -errorcode [list CLOCK wrongNumArgs] \
+	    "wrong \# args: should be\
+             \"$cmdName string\
+             ?-base seconds?\
+             ?-format string? ?-gmt boolean?\
+             ?-locale LOCALE? ?-timezone ZONE?\""
+    }
+
+    # Set defaults
+
+    set base [clock seconds]
+    set string [lindex $args 0]
+    set format {}
+    set gmt 0
+    set locale c
+    set timezone [GetSystemTimeZone]
+
+    # Pick up command line options.
+
+    foreach { flag value } [lreplace $args 0 0] {
+	set saw($flag) {}
+	switch -exact -- $flag {
+	    -b - -ba - -bas - -base {
+		set base $value
+	    }
+	    -f - -fo - -for - -form - -forma - -format {
+		set format $value
+	    }
+	    -g - -gm - -gmt {
+		set gmt $value
+	    }
+	    -l - -lo - -loc - -loca - -local - -locale {
+		set locale [string tolower $value]
+	    }
+	    -t - -ti - -tim - -time - -timez - -timezo - -timezon - -timezone {
+		set timezone $value
+	    }
+	    default {
+		return -code error \
+		    -errorcode [list CLOCK badOption $flag] \
+		    "bad option \"$flag\",\
+                     must be -base, -format, -gmt, -locale or -timezone"
+	    }
+	}
+    }
+
+    # Check options for validity
+
+    if { [info exists saw(-gmt)] && [info exists saw(-timezone)] } {
+	return -code error \
+	    -errorcode [list CLOCK gmtWithTimezone] \
+	    "cannot use -gmt and -timezone in same call"
+    }
+    if { [catch { expr { wide($base) } } result] } {
+	return -code error "expected integer but got \"$base\""
+    }
+    if { ![string is boolean -strict $gmt] } {
+	return -code error "expected boolean value but got \"$gmt\""
+    } elseif { $gmt } {
+	set timezone :GMT
+    }
+
+    if { ![info exists saw(-format)] } {
+	# Perhaps someday we'll localize the legacy code. Right now, it's not
+	# localized.
+	if { [info exists saw(-locale)] } {
+	    return -code error \
+		-errorcode [list CLOCK flagWithLegacyFormat] \
+		"legacy \[clock scan\] does not support -locale"
+
+	}
+	return [FreeScan $string $base $timezone $locale]
+    }
+
+    # Change locale if a fresh locale has been given on the command line.
+
+    EnterLocale $locale
+
+    try {
+	# Map away the locale-dependent composite format groups
+
+	set scanner [ParseClockScanFormat $format $locale]
+	return [$scanner $string $base $timezone]
+    } trap CLOCK {result opts} {
+	# Conceal location of generation of expected errors
+	dict unset opts -errorinfo
+	return -options $opts $result
+    }
 }
 
-# mcMerge --
+#----------------------------------------------------------------------
+#
+# FreeScan --
 #
-#	Merge message catalog dictionaries to one dictionary.
+#	Scans a time in free format
 #
-# Arguments:
-#	locales		List of locales to merge.
+# Parameters:
+#	string - String containing the time to scan
+#	base - Base time, expressed in seconds from the Epoch
+#	timezone - Default time zone in which the time will be expressed
+#	locale - (Unused) Name of the locale where the time will be scanned.
 #
 # Results:
-#	Returns the (weak pointer) to merged dictionary of message catalog.
-#
-proc mcMerge {locales} {
-    variable mcMergedCat
-    if {[dict exists $mcMergedCat [set loc [lindex $locales 0]]]} {
-	set mrgcat [dict get $mcMergedCat $loc]
-	return [dict smartref $mrgcat]
-    }
-    # package msgcat currently does not provide possibility to get whole catalog:
-    upvar ::msgcat::Msgs Msgs
-    set ns ::tcl::clock
-    # Merge sequential locales (in reverse order, e. g. {} -> en -> en_en):
-    if {[llength $locales] > 1} {
-	set mrgcat [mcMerge [lrange $locales 1 end]]
-	if {[dict exists $Msgs $ns $loc]} {
-	    set mrgcat [dict merge $mrgcat [dict get $Msgs $ns $loc]]
+#	Returns the date and time extracted from the string in seconds from
+#	the epoch
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::FreeScan { string base timezone locale } {
+
+    variable TZData
+
+    # Get the data for time changes in the given zone
+
+    try {
+	SetupTimeZone $timezone
+    } on error {retval opts} {
+	dict unset opts -errorinfo
+	return -options $opts $retval
+    }
+
+    # Extract year, month and day from the base time for the parser to use as
+    # defaults
+
+    set date [GetDateFields $base $TZData($timezone) 2361222]
+    dict set date secondOfDay [expr {
+	[dict get $date localSeconds] % 86400
+    }]
+
+    # Parse the date.  The parser will return a list comprising date, time,
+    # time zone, relative month/day/seconds, relative weekday, ordinal month.
+
+    try {
+	set scanned [Oldscan $string \
+		     [dict get $date year] \
+		     [dict get $date month] \
+		     [dict get $date dayOfMonth]]
+	lassign $scanned \
+	    parseDate parseTime parseZone parseRel \
+	    parseWeekday parseOrdinalMonth
+    } on error message {
+	return -code error \
+	    "unable to convert date-time string \"$string\": $message"
+    }
+
+    # If the caller supplied a date in the string, update the 'date' dict with
+    # the value. If the caller didn't specify a time with the date, default to
+    # midnight.
+
+    if { [llength $parseDate] > 0 } {
+	lassign $parseDate y m d
+	if { $y < 100 } {
+	    if { $y >= 39 } {
+		incr y 1900
+	    } else {
+		incr y 2000
+	    }
 	}
-    } else {
-	if {[dict exists $Msgs $ns $loc]} {
-	    set mrgcat [dict get $Msgs $ns $loc]
+	dict set date era CE
+	dict set date year $y
+	dict set date month $m
+	dict set date dayOfMonth $d
+	if { $parseTime eq {} } {
+	    set parseTime 0
+	}
+    }
+
+    # If the caller supplied a time zone in the string, it comes back as a
+    # two-element list; the first element is the number of minutes east of
+    # Greenwich, and the second is a Daylight Saving Time indicator (1 == yes,
+    # 0 == no, -1 == unknown). We make it into a time zone indicator of
+    # +-hhmm.
+
+    if { [llength $parseZone] > 0 } {
+	lassign $parseZone minEast dstFlag
+	set timezone [FormatNumericTimeZone \
+			  [expr { 60 * $minEast + 3600 * $dstFlag }]]
+	SetupTimeZone $timezone
+    }
+    dict set date tzName $timezone
+
+    # Assemble date, time, zone into seconds-from-epoch
+
+    set date [GetJulianDayFromEraYearMonthDay $date[set date {}] 2361222]
+    if { $parseTime ne {} } {
+	dict set date secondOfDay $parseTime
+    } elseif { [llength $parseWeekday] != 0
+	       || [llength $parseOrdinalMonth] != 0
+	       || ( [llength $parseRel] != 0
+		    && ( [lindex $parseRel 0] != 0
+			 || [lindex $parseRel 1] != 0 ) ) } {
+	dict set date secondOfDay 0
+    }
+
+    dict set date localSeconds [expr {
+	-210866803200
+	+ ( 86400 * wide([dict get $date julianDay]) )
+	+ [dict get $date secondOfDay]
+    }]
+    dict set date tzName $timezone
+    set date [ConvertLocalToUTC $date[set date {}] $TZData($timezone) 2361222]
+    set seconds [dict get $date seconds]
+
+    # Do relative times
+
+    if { [llength $parseRel] > 0 } {
+	lassign $parseRel relMonth relDay relSecond
+	set seconds [add $seconds \
+			 $relMonth months $relDay days $relSecond seconds \
+			 -timezone $timezone -locale $locale]
+    }
+
+    # Do relative weekday
+
+    if { [llength $parseWeekday] > 0 } {
+	lassign $parseWeekday dayOrdinal dayOfWeek
+	set date2 [GetDateFields $seconds $TZData($timezone) 2361222]
+	dict set date2 era CE
+	set jdwkday [WeekdayOnOrBefore $dayOfWeek [expr {
+	    [dict get $date2 julianDay] + 6
+	}]]
+	incr jdwkday [expr { 7 * $dayOrdinal }]
+	if { $dayOrdinal > 0 } {
+	    incr jdwkday -7
+	}
+	dict set date2 secondOfDay \
+	    [expr { [dict get $date2 localSeconds] % 86400 }]
+	dict set date2 julianDay $jdwkday
+	dict set date2 localSeconds [expr {
+	    -210866803200
+	    + ( 86400 * wide([dict get $date2 julianDay]) )
+	    + [dict get $date secondOfDay]
+	}]
+	dict set date2 tzName $timezone
+	set date2 [ConvertLocalToUTC $date2[set date2 {}] $TZData($timezone) \
+		       2361222]
+	set seconds [dict get $date2 seconds]
+
+    }
+
+    # Do relative month
+
+    if { [llength $parseOrdinalMonth] > 0 } {
+	lassign $parseOrdinalMonth monthOrdinal monthNumber
+	if { $monthOrdinal > 0 } {
+	    set monthDiff [expr { $monthNumber - [dict get $date month] }]
+	    if { $monthDiff <= 0 } {
+		incr monthDiff 12
+	    }
+	    incr monthOrdinal -1
 	} else {
-	    set mrgcat [dict create]
+	    set monthDiff [expr { [dict get $date month] - $monthNumber }]
+	    if { $monthDiff >= 0 } {
+		incr monthDiff -12
+	    }
+	    incr monthOrdinal
+	}
+	set seconds [add $seconds $monthOrdinal years $monthDiff months \
+			 -timezone $timezone -locale $locale]
+    }
+
+    return $seconds
+}
+
+
+#----------------------------------------------------------------------
+#
+# ParseClockScanFormat --
+#
+#	Parses a format string given to [clock scan -format]
+#
+# Parameters:
+#	formatString - The format being parsed
+#	locale - The current locale
+#
+# Results:
+#	Constructs and returns a procedure that accepts the string being
+#	scanned, the base time, and the time zone.  The procedure will either
+#	return the scanned time or else throw an error that should be rethrown
+#	to the caller of [clock scan]
+#
+# Side effects:
+#	The given procedure is defined in the ::tcl::clock namespace.  Scan
+#	procedures are not deleted once installed.
+#
+# Why do we parse dates by defining a procedure to parse them?  The reason is
+# that by doing so, we have one convenient place to cache all the information:
+# the regular expressions that match the patterns (which will be compiled),
+# the code that assembles the date information, everything lands in one place.
+# In this way, when a given format is reused at run time, all the information
+# of how to apply it is available in a single place.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::ParseClockScanFormat {formatString locale} {
+    # Check whether the format has been parsed previously, and return the
+    # existing recognizer if it has.
+
+    set procName scanproc'$formatString'$locale
+    set procName [namespace current]::[string map {: {\:} \\ {\\}} $procName]
+    if { [namespace which $procName] != {} } {
+	return $procName
+    }
+
+    variable DateParseActions
+    variable TimeParseActions
+
+    # Localize the %x, %X, etc. groups
+
+    set formatString [LocalizeFormat $locale $formatString]
+
+    # Condense whitespace
+
+    regsub -all {[[:space:]]+} $formatString { } formatString
+
+    # Walk through the groups of the format string.  In this loop, we
+    # accumulate:
+    #	- a regular expression that matches the string,
+    #   - the count of capturing brackets in the regexp
+    #   - a set of code that post-processes the fields captured by the regexp,
+    #   - a dictionary whose keys are the names of fields that are present
+    #     in the format string.
+
+    set re {^[[:space:]]*}
+    set captureCount 0
+    set postcode {}
+    set fieldSet [dict create]
+    set fieldCount 0
+    set postSep {}
+    set state {}
+
+    foreach c [split $formatString {}] {
+	switch -exact -- $state {
+	    {} {
+		if { $c eq "%" } {
+		    set state %
+		} elseif { $c eq " " } {
+		    append re {[[:space:]]+}
+		} else {
+		    if { ! [string is alnum $c] } {
+			append re "\\"
+		    }
+		    append re $c
+		}
+	    }
+	    % {
+		set state {}
+		switch -exact -- $c {
+		    % {
+			append re %
+		    }
+		    { } {
+			append re "\[\[:space:\]\]*"
+		    }
+		    a - A { 		# Day of week, in words
+			set l {}
+			foreach \
+			    i {7 1 2 3 4 5 6} \
+			    abr [mc DAYS_OF_WEEK_ABBREV] \
+			    full [mc DAYS_OF_WEEK_FULL] {
+				dict set l [string tolower $abr] $i
+				dict set l [string tolower $full] $i
+				incr i
+			    }
+			lassign [UniquePrefixRegexp $l] regex lookup
+			append re ( $regex )
+			dict set fieldSet dayOfWeek [incr fieldCount]
+			append postcode "dict set date dayOfWeek \[" \
+			    "dict get " [list $lookup] " " \
+			    \[ {string tolower $field} [incr captureCount] \] \
+			    "\]\n"
+		    }
+		    b - B - h {		# Name of month
+			set i 0
+			set l {}
+			foreach \
+			    abr [mc MONTHS_ABBREV] \
+			    full [mc MONTHS_FULL] {
+				incr i
+				dict set l [string tolower $abr] $i
+				dict set l [string tolower $full] $i
+			    }
+			lassign [UniquePrefixRegexp $l] regex lookup
+			append re ( $regex )
+			dict set fieldSet month [incr fieldCount]
+			append postcode "dict set date month \[" \
+			    "dict get " [list $lookup] \
+			    " " \[ {string tolower $field} \
+			    [incr captureCount] \] \
+			    "\]\n"
+		    }
+		    C {			# Gregorian century
+			append re \\s*(\\d\\d?)
+			dict set fieldSet century [incr fieldCount]
+			append postcode "dict set date century \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    d - e {		# Day of month
+			append re \\s*(\\d\\d?)
+			dict set fieldSet dayOfMonth [incr fieldCount]
+			append postcode "dict set date dayOfMonth \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    E {			# Prefix for locale-specific codes
+			set state %E
+		    }
+		    g {			# ISO8601 2-digit year
+			append re \\s*(\\d\\d)
+			dict set fieldSet iso8601YearOfCentury \
+			    [incr fieldCount]
+			append postcode \
+			    "dict set date iso8601YearOfCentury \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    G {			# ISO8601 4-digit year
+			append re \\s*(\\d\\d)(\\d\\d)
+			dict set fieldSet iso8601Century [incr fieldCount]
+			dict set fieldSet iso8601YearOfCentury \
+			    [incr fieldCount]
+			append postcode \
+			    "dict set date iso8601Century \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n" \
+			    "dict set date iso8601YearOfCentury \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    H - k {		# Hour of day
+			append re \\s*(\\d\\d?)
+			dict set fieldSet hour [incr fieldCount]
+			append postcode "dict set date hour \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    I - l {		# Hour, AM/PM
+			append re \\s*(\\d\\d?)
+			dict set fieldSet hourAMPM [incr fieldCount]
+			append postcode "dict set date hourAMPM \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    j {			# Day of year
+			append re \\s*(\\d\\d?\\d?)
+			dict set fieldSet dayOfYear [incr fieldCount]
+			append postcode "dict set date dayOfYear \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    J {			# Julian Day Number
+			append re \\s*(\\d+)
+			dict set fieldSet julianDay [incr fieldCount]
+			append postcode "dict set date julianDay \[" \
+			    "::scan \$field" [incr captureCount] " %ld" \
+			    "\]\n"
+		    }
+		    m - N {		# Month number
+			append re \\s*(\\d\\d?)
+			dict set fieldSet month [incr fieldCount]
+			append postcode "dict set date month \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    M {			# Minute
+			append re \\s*(\\d\\d?)
+			dict set fieldSet minute [incr fieldCount]
+			append postcode "dict set date minute \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    n {			# Literal newline
+			append re \\n
+		    }
+		    O {			# Prefix for locale numerics
+			set state %O
+		    }
+		    p - P { 		# AM/PM indicator
+			set l [list [string tolower [mc AM]] 0 \
+				   [string tolower [mc PM]] 1]
+			lassign [UniquePrefixRegexp $l] regex lookup
+			append re ( $regex )
+			dict set fieldSet amPmIndicator [incr fieldCount]
+			append postcode "dict set date amPmIndicator \[" \
+			    "dict get " [list $lookup] " \[string tolower " \
+			    "\$field" \
+			    [incr captureCount] \
+			    "\]\]\n"
+		    }
+		    Q {			# Hi, Jeff!
+			append re {Stardate\s+([-+]?\d+)(\d\d\d)[.](\d)}
+			incr captureCount
+			dict set fieldSet seconds [incr fieldCount]
+			append postcode {dict set date seconds } \[ \
+			    {ParseStarDate $field} [incr captureCount] \
+			    { $field} [incr captureCount] \
+			    { $field} [incr captureCount] \
+			    \] \n
+		    }
+		    s {			# Seconds from Posix Epoch
+			# This next case is insanely difficult, because it's
+			# problematic to determine whether the field is
+			# actually within the range of a wide integer.
+			append re {\s*([-+]?\d+)}
+			dict set fieldSet seconds [incr fieldCount]
+			append postcode {dict set date seconds } \[ \
+			    {ScanWide $field} [incr captureCount] \] \n
+		    }
+		    S {			# Second
+			append re \\s*(\\d\\d?)
+			dict set fieldSet second [incr fieldCount]
+			append postcode "dict set date second \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    t {			# Literal tab character
+			append re \\t
+		    }
+		    u - w {		# Day number within week, 0 or 7 == Sun
+					# 1=Mon, 6=Sat
+			append re \\s*(\\d)
+			dict set fieldSet dayOfWeek [incr fieldCount]
+			append postcode {::scan $field} [incr captureCount] \
+			    { %d dow} \n \
+			    {
+				if { $dow == 0 } {
+				    set dow 7
+				} elseif { $dow > 7 } {
+				    return -code error \
+					-errorcode [list CLOCK badDayOfWeek] \
+					"day of week is greater than 7"
+				}
+				dict set date dayOfWeek $dow
+			    }
+		    }
+		    U {			# Week of year. The first Sunday of
+					# the year is the first day of week
+					# 01. No scan rule uses this group.
+			append re \\s*\\d\\d?
+		    }
+		    V {			# Week of ISO8601 year
+
+			append re \\s*(\\d\\d?)
+			dict set fieldSet iso8601Week [incr fieldCount]
+			append postcode "dict set date iso8601Week \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    W {			# Week of the year (00-53). The first
+					# Monday of the year is the first day
+					# of week 01. No scan rule uses this
+					# group.
+			append re \\s*\\d\\d?
+		    }
+		    y {			# Two-digit Gregorian year
+			append re \\s*(\\d\\d?)
+			dict set fieldSet yearOfCentury [incr fieldCount]
+			append postcode "dict set date yearOfCentury \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    Y {			# 4-digit Gregorian year
+			append re \\s*(\\d\\d)(\\d\\d)
+			dict set fieldSet century [incr fieldCount]
+			dict set fieldSet yearOfCentury [incr fieldCount]
+			append postcode \
+			    "dict set date century \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n" \
+			    "dict set date yearOfCentury \[" \
+			    "::scan \$field" [incr captureCount] " %d" \
+			    "\]\n"
+		    }
+		    z - Z {			# Time zone name
+			append re {(?:([-+]\d\d(?::?\d\d(?::?\d\d)?)?)|([[:alnum:]]{1,4}))}
+			dict set fieldSet tzName [incr fieldCount]
+			append postcode \
+			    {if } \{ { $field} [incr captureCount] \
+			    { ne "" } \} { } \{ \n \
+			    {dict set date tzName $field} \
+			    $captureCount \n \
+			    \} { else } \{ \n \
+			    {dict set date tzName } \[ \
+			    {ConvertLegacyTimeZone $field} \
+			    [incr captureCount] \] \n \
+			    \} \n \
+		    }
+		    % {			# Literal percent character
+			append re %
+		    }
+		    default {
+			append re %
+			if { ! [string is alnum $c] } {
+			    append re \\
+			    }
+			append re $c
+		    }
+		}
+	    }
+	    %E {
+		switch -exact -- $c {
+		    C {			# Locale-dependent era
+			set d {}
+			foreach triple [mc LOCALE_ERAS] {
+			    lassign $triple t symbol year
+			    dict set d [string tolower $symbol] $year
+			}
+			lassign [UniquePrefixRegexp $d] regex lookup
+			append re (?: $regex )
+		    }
+		    E {
+			set l {}
+			dict set l [string tolower [mc BCE]] BCE
+			dict set l [string tolower [mc CE]] CE
+			dict set l b.c.e. BCE
+			dict set l c.e. CE
+			dict set l b.c. BCE
+			dict set l a.d. CE
+			lassign [UniquePrefixRegexp $l] regex lookup
+			append re ( $regex )
+			dict set fieldSet era [incr fieldCount]
+			append postcode "dict set date era \["\
+			    "dict get " [list $lookup] \
+			    { } \[ {string tolower $field} \
+			    [incr captureCount] \] \
+			    "\]\n"
+		    }
+		    y {			# Locale-dependent year of the era
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			incr captureCount
+		    }
+		    default {
+			append re %E
+			if { ! [string is alnum $c] } {
+			    append re \\
+			    }
+			append re $c
+		    }
+		}
+		set state {}
+	    }
+	    %O {
+		switch -exact -- $c {
+		    d - e {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet dayOfMonth [incr fieldCount]
+			append postcode "dict set date dayOfMonth \[" \
+			    "dict get " [list $lookup] " \$field" \
+			    [incr captureCount] \
+			    "\]\n"
+		    }
+		    H - k {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet hour [incr fieldCount]
+			append postcode "dict set date hour \[" \
+			    "dict get " [list $lookup] " \$field" \
+			    [incr captureCount] \
+			    "\]\n"
+		    }
+		    I - l {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet hourAMPM [incr fieldCount]
+			append postcode "dict set date hourAMPM \[" \
+			    "dict get " [list $lookup] " \$field" \
+			    [incr captureCount] \
+			    "\]\n"
+		    }
+		    m {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet month [incr fieldCount]
+			append postcode "dict set date month \[" \
+			    "dict get " [list $lookup] " \$field" \
+			    [incr captureCount] \
+			    "\]\n"
+		    }
+		    M {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet minute [incr fieldCount]
+			append postcode "dict set date minute \[" \
+			    "dict get " [list $lookup] " \$field" \
+			    [incr captureCount] \
+			    "\]\n"
+		    }
+		    S {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet second [incr fieldCount]
+			append postcode "dict set date second \[" \
+			    "dict get " [list $lookup] " \$field" \
+			    [incr captureCount] \
+			    "\]\n"
+		    }
+		    u - w {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet dayOfWeek [incr fieldCount]
+			append postcode "set dow \[dict get " [list $lookup] \
+			    { $field} [incr captureCount] \] \n \
+			    {
+				if { $dow == 0 } {
+				    set dow 7
+				} elseif { $dow > 7 } {
+				    return -code error \
+					-errorcode [list CLOCK badDayOfWeek] \
+					"day of week is greater than 7"
+				}
+				dict set date dayOfWeek $dow
+			    }
+		    }
+		    y {
+			lassign [LocaleNumeralMatcher $locale] regex lookup
+			append re $regex
+			dict set fieldSet yearOfCentury [incr fieldCount]
+			append postcode {dict set date yearOfCentury } \[ \
+			    {dict get } [list $lookup] { $field} \
+			    [incr captureCount] \] \n
+		    }
+		    default {
+			append re %O
+			if { ! [string is alnum $c] } {
+			    append re \\
+			    }
+			append re $c
+		    }
+		}
+		set state {}
+	    }
+	}
+    }
+
+    # Clean up any unfinished format groups
+
+    append re $state \\s*\$
+
+    # Build the procedure
+
+    set procBody {}
+    append procBody "variable ::tcl::clock::TZData" \n
+    append procBody "if \{ !\[ regexp -nocase [list $re] \$string ->"
+    for { set i 1 } { $i <= $captureCount } { incr i } {
+	append procBody " " field $i
+    }
+    append procBody "\] \} \{" \n
+    append procBody {
+	return -code error -errorcode [list CLOCK badInputString] \
+	    {input string does not match supplied format}
+    }
+    append procBody \}\n
+    append procBody "set date \[dict create\]" \n
+    append procBody {dict set date tzName $timeZone} \n
+    append procBody $postcode
+    append procBody [list set changeover [mc GREGORIAN_CHANGE_DATE]] \n
+
+    # Set up the time zone before doing anything with a default base date
+    # that might need a timezone to interpret it.
+
+    if { ![dict exists $fieldSet seconds]
+	    && ![dict exists $fieldSet starDate] } {
+	if { [dict exists $fieldSet tzName] } {
+	    append procBody {
+		set timeZone [dict get $date tzName]
+	    }
+	}
+	append procBody {
+	    ::tcl::clock::SetupTimeZone $timeZone
+	}
+    }
+
+    # Add code that gets Julian Day Number from the fields.
+
+    append procBody [MakeParseCodeFromFields $fieldSet $DateParseActions]
+
+    # Get time of day
+
+    append procBody [MakeParseCodeFromFields $fieldSet $TimeParseActions]
+
+    # Assemble seconds from the Julian day and second of the day.
+    # Convert to local time unless epoch seconds or stardate are
+    # being processed - they're always absolute
+
+    if { ![dict exists $fieldSet seconds]
+         && ![dict exists $fieldSet starDate] } {
+	append procBody {
+	    if { [dict get $date julianDay] > 5373484 } {
+		return -code error -errorcode [list CLOCK dateTooLarge] \
+		    "requested date too large to represent"
+	    }
+	    dict set date localSeconds [expr {
+		-210866803200
+		+ ( 86400 * wide([dict get $date julianDay]) )
+		+ [dict get $date secondOfDay]
+	    }]
+	}
+
+	# Finally, convert the date to local time
+
+	append procBody {
+	    set date [::tcl::clock::ConvertLocalToUTC $date[set date {}] \
+			  $TZData($timeZone) $changeover]
+	}
+    }
+
+    # Return result
+
+    append procBody {return [dict get $date seconds]} \n
+
+    proc $procName { string baseTime timeZone } $procBody
+
+    # puts [list proc $procName [list string baseTime timeZone] $procBody]
+
+    return $procName
+}
+
+#----------------------------------------------------------------------
+#
+# LocaleNumeralMatcher --
+#
+#	Composes a regexp that captures the numerals in the given locale, and
+#	a dictionary to map them to conventional numerals.
+#
+# Parameters:
+#	locale - Name of the current locale
+#
+# Results:
+#	Returns a two-element list comprising the regexp and the dictionary.
+#
+# Side effects:
+#	Caches the result.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::LocaleNumeralMatcher {l} {
+    variable LocaleNumeralCache
+
+    if { ![dict exists $LocaleNumeralCache $l] } {
+	set d {}
+	set i 0
+	set sep \(
+	foreach n [mc LOCALE_NUMERALS] {
+	    dict set d $n $i
+	    regsub -all {[^[:alnum:]]} $n \\\\& subex
+	    append re $sep $subex
+	    set sep |
+	    incr i
+	}
+	append re \)
+	dict set LocaleNumeralCache $l [list $re $d]
+    }
+    return [dict get $LocaleNumeralCache $l]
+}
+
+
+
+#----------------------------------------------------------------------
+#
+# UniquePrefixRegexp --
+#
+#	Composes a regexp that performs unique-prefix matching.  The RE
+#	matches one of a supplied set of strings, or any unique prefix
+#	thereof.
+#
+# Parameters:
+#	data - List of alternating match-strings and values.
+#	       Match-strings with distinct values are considered
+#	       distinct.
+#
+# Results:
+#	Returns a two-element list.  The first is a regexp that matches any
+#	unique prefix of any of the strings.  The second is a dictionary whose
+#	keys are match values from the regexp and whose values are the
+#	corresponding values from 'data'.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::UniquePrefixRegexp { data } {
+    # The 'successors' dictionary will contain, for each string that is a
+    # prefix of any key, all characters that may follow that prefix.  The
+    # 'prefixMapping' dictionary will have keys that are prefixes of keys and
+    # values that correspond to the keys.
+
+    set prefixMapping [dict create]
+    set successors [dict create {} {}]
+
+    # Walk the key-value pairs
+
+    foreach { key value } $data {
+	# Construct all prefixes of the key;
+
+	set prefix {}
+	foreach char [split $key {}] {
+	    set oldPrefix $prefix
+	    dict set successors $oldPrefix $char {}
+	    append prefix $char
+
+	    # Put the prefixes in the 'prefixMapping' and 'successors'
+	    # dictionaries
+
+	    dict lappend prefixMapping $prefix $value
+	    if { ![dict exists $successors $prefix] } {
+		dict set successors $prefix {}
+	    }
 	}
     }
-    dict set mcMergedCat $loc $mrgcat
-    # return smart reference (shared dict as object with exact one ref-counter)
-    return [dict smartref $mrgcat]
+
+    # Identify those prefixes that designate unique values, and those that are
+    # the full keys
+
+    set uniquePrefixMapping {}
+    dict for { key valueList } $prefixMapping {
+	if { [llength $valueList] == 1 } {
+	    dict set uniquePrefixMapping $key [lindex $valueList 0]
+	}
+    }
+    foreach { key value } $data {
+	dict set uniquePrefixMapping $key $value
+    }
+
+    # Construct the re.
+
+    return [list \
+		[MakeUniquePrefixRegexp $successors $uniquePrefixMapping {}] \
+		$uniquePrefixMapping]
 }
 
 #----------------------------------------------------------------------
 #
-# GetSystemLocale --
+# MakeUniquePrefixRegexp --
 #
-#	Determines the system locale, which corresponds to "system"
-#	keyword for locale parameter of 'clock' command.
+#	Service procedure for 'UniquePrefixRegexp' that constructs a regular
+#	expresison that matches the unique prefixes.
 #
 # Parameters:
+#	successors - Dictionary whose keys are all prefixes
+#		     of keys passed to 'UniquePrefixRegexp' and whose
+#		     values are dictionaries whose keys are the characters
+#		     that may follow those prefixes.
+#	uniquePrefixMapping - Dictionary whose keys are the unique
+#			      prefixes and whose values are not examined.
+#	prefixString - Current prefix being processed.
+#
+# Results:
+#	Returns a constructed regular expression that matches the set of
+#	unique prefixes beginning with the 'prefixString'.
+#
+# Side effects:
 #	None.
 #
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::MakeUniquePrefixRegexp { successors
+					  uniquePrefixMapping
+					  prefixString } {
+
+    # Get the characters that may follow the current prefix string
+
+    set schars [lsort -ascii [dict keys [dict get $successors $prefixString]]]
+    if { [llength $schars] == 0 } {
+	return {}
+    }
+
+    # If there is more than one successor character, or if the current prefix
+    # is a unique prefix, surround the generated re with non-capturing
+    # parentheses.
+
+    set re {}
+    if {
+	[dict exists $uniquePrefixMapping $prefixString]
+	|| [llength $schars] > 1
+    } then {
+	append re "(?:"
+    }
+
+    # Generate a regexp that matches the successors.
+
+    set sep ""
+    foreach { c } $schars {
+	set nextPrefix $prefixString$c
+	regsub -all {[^[:alnum:]]} $c \\\\& rechar
+	append re $sep $rechar \
+	    [MakeUniquePrefixRegexp \
+		 $successors $uniquePrefixMapping $nextPrefix]
+	set sep |
+    }
+
+    # If the current prefix is a unique prefix, make all following text
+    # optional. Otherwise, if there is more than one successor character,
+    # close the non-capturing parentheses.
+
+    if { [dict exists $uniquePrefixMapping $prefixString] } {
+	append re ")?"
+    } elseif { [llength $schars] > 1 } {
+	append re ")"
+    }
+
+    return $re
+}
+
+#----------------------------------------------------------------------
+#
+# MakeParseCodeFromFields --
+#
+#	Composes Tcl code to extract the Julian Day Number from a dictionary
+#	containing date fields.
+#
+# Parameters:
+#	dateFields -- Dictionary whose keys are fields of the date,
+#	              and whose values are the rightmost positions
+#		      at which those fields appear.
+#	parseActions -- List of triples: field set, priority, and
+#			code to emit.  Smaller priorities are better, and
+#			the list must be in ascending order by priority
+#
 # Results:
-#	Returns the system locale.
+#	Returns a burst of code that extracts the day number from the given
+#	date.
 #
 # Side effects:
-#	None
+#	None.
 #
 #----------------------------------------------------------------------
 
-proc ::tcl::clock::GetSystemLocale {} {
-    if { $::tcl_platform(platform) ne {windows} } {
-	# On a non-windows platform, the 'system' locale is the same as
-	# the 'current' locale
+proc ::tcl::clock::MakeParseCodeFromFields { dateFields parseActions } {
 
-	return [mclocale]
+    set currPrio 999
+    set currFieldPos [list]
+    set currCodeBurst {
+	error "in ::tcl::clock::MakeParseCodeFromFields: can't happen"
     }
 
-    # On a windows platform, the 'system' locale is adapted from the
-    # 'current' locale by applying the date and time formats from the
-    # Control Panel.  First, load the 'current' locale if it's not yet
-    # loaded
+    foreach { fieldSet prio parseAction } $parseActions {
+	# If we've found an answer that's better than any that follow, quit
+	# now.
+
+	if { $prio > $currPrio } {
+	    break
+	}
+
+	# Accumulate the field positions that are used in the current field
+	# grouping.
+
+	set fieldPos [list]
+	set ok true
+	foreach field $fieldSet {
+	    if { ! [dict exists $dateFields $field] } {
+		set ok 0
+		break
+	    }
+	    lappend fieldPos [dict get $dateFields $field]
+	}
+
+	# Quit if we don't have a complete set of fields
+	if { !$ok } {
+	    continue
+	}
+
+	# Determine whether the current answer is better than the last.
+
+	set fPos [lsort -integer -decreasing $fieldPos]
 
-    mcpackagelocale set [mclocale]
+	if { $prio ==  $currPrio } {
+	    foreach currPos $currFieldPos newPos $fPos {
+		if {
+		    ![string is integer $newPos]
+		    || ![string is integer $currPos]
+		    || $newPos > $currPos
+		} then {
+		    break
+		}
+		if { $newPos < $currPos } {
+		    set ok 0
+		    break
+		}
+	    }
+	}
+	if { !$ok } {
+	    continue
+	}
 
-    # Make a new locale string for the system locale, and get the
-    # Control Panel information
+	# Remember the best possibility for extracting date information
 
-    set locale [mclocale]_windows
-    if { ! [mcpackagelocale present $locale] } {
-	LoadWindowsDateTimeFormats $locale
+	set currPrio $prio
+	set currFieldPos $fPos
+	set currCodeBurst $parseAction
     }
 
-    return $locale
+    return $currCodeBurst
 }
 
 #----------------------------------------------------------------------
@@ -667,14 +2303,34 @@ proc ::tcl::clock::GetSystemLocale {} {
 #----------------------------------------------------------------------
 
 proc ::tcl::clock::EnterLocale { locale } {
-    switch -- $locale system {
-    	set locale [GetSystemLocale]
-    } current {
+    if { $locale eq {system} } {
+	if { $::tcl_platform(platform) ne {windows} } {
+	    # On a non-windows platform, the 'system' locale is the same as
+	    # the 'current' locale
+
+	    set locale current
+	} else {
+	    # On a windows platform, the 'system' locale is adapted from the
+	    # 'current' locale by applying the date and time formats from the
+	    # Control Panel.  First, load the 'current' locale if it's not yet
+	    # loaded
+
+	    mcpackagelocale set [mclocale]
+
+	    # Make a new locale string for the system locale, and get the
+	    # Control Panel information
+
+	    set locale [mclocale]_windows
+	    if { ! [mcpackagelocale present $locale] } {
+		LoadWindowsDateTimeFormats $locale
+	    }
+	}
+    }
+    if { $locale eq {current}} {
 	set locale [mclocale]
     }
-    # Select the locale, eventually load it
+    # Eventually load the locale
     mcpackagelocale set $locale
-    return $locale
 }
 
 #----------------------------------------------------------------------
@@ -824,64 +2480,485 @@ proc ::tcl::clock::LoadWindowsDateTimeFormats { locale } {
 #
 #----------------------------------------------------------------------
 
-proc ::tcl::clock::LocalizeFormat { locale format {fmtkey {}} } {
-    variable LocaleFormats
+proc ::tcl::clock::LocalizeFormat { locale format } {
 
-    if { $fmtkey eq {} } { set fmtkey FMT_$format }
-    if { [catch {
-    	set locfmt [dict get $LocaleFormats $locale $fmtkey]
-    }] } {
+    # message catalog key to cache this format
+    set key FORMAT_$format
 
-    	# get map list cached or build it:
-	if { [catch {
-	    set mlst [dict get $LocaleFormats $locale MLST]
-	}] } {
+    if { [::msgcat::mcexists -exactlocale -exactnamespace $key] } {
+	return [mc $key]
+    }
+    # Handle locale-dependent format groups by mapping them out of the format
+    # string.  Note that the order of the [string map] operations is
+    # significant because later formats can refer to later ones; for example
+    # %c can refer to %X, which in turn can refer to %T.
+
+    set list {
+	%% %%
+	%D %m/%d/%Y
+	%+ {%a %b %e %H:%M:%S %Z %Y}
+    }
+    lappend list %EY [string map $list [mc LOCALE_YEAR_FORMAT]]
+    lappend list %T  [string map $list [mc TIME_FORMAT_24_SECS]]
+    lappend list %R  [string map $list [mc TIME_FORMAT_24]]
+    lappend list %r  [string map $list [mc TIME_FORMAT_12]]
+    lappend list %X  [string map $list [mc TIME_FORMAT]]
+    lappend list %EX [string map $list [mc LOCALE_TIME_FORMAT]]
+    lappend list %x  [string map $list [mc DATE_FORMAT]]
+    lappend list %Ex [string map $list [mc LOCALE_DATE_FORMAT]]
+    lappend list %c  [string map $list [mc DATE_TIME_FORMAT]]
+    lappend list %Ec [string map $list [mc LOCALE_DATE_TIME_FORMAT]]
+    set format [string map $list $format]
+
+    ::msgcat::mcset $locale $key $format
+    return $format
+}
 
-	    # message catalog dictionary:
-	    set mcd [mcget $locale]
+#----------------------------------------------------------------------
+#
+# FormatNumericTimeZone --
+#
+#	Formats a time zone as +hhmmss
+#
+# Parameters:
+#	z - Time zone in seconds east of Greenwich
+#
+# Results:
+#	Returns the time zone formatted in a numeric form
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
 
-	    # Handle locale-dependent format groups by mapping them out of the format
-	    # string.  Note that the order of the [string map] operations is
-	    # significant because later formats can refer to later ones; for example
-	    # %c can refer to %X, which in turn can refer to %T.
+proc ::tcl::clock::FormatNumericTimeZone { z } {
+    if { $z < 0 } {
+	set z [expr { - $z }]
+	set retval -
+    } else {
+	set retval +
+    }
+    append retval [::format %02d [expr { $z / 3600 }]]
+    set z [expr { $z % 3600 }]
+    append retval [::format %02d [expr { $z / 60 }]]
+    set z [expr { $z % 60 }]
+    if { $z != 0 } {
+	append retval [::format %02d $z]
+    }
+    return $retval
+}
 
-	    set mlst {
-		%% %%
-		%D %m/%d/%Y
-		%+ {%a %b %e %H:%M:%S %Z %Y}
-	    }
-	    lappend mlst %EY [string map $mlst [dict get $mcd LOCALE_YEAR_FORMAT]]
-	    lappend mlst %T  [string map $mlst [dict get $mcd TIME_FORMAT_24_SECS]]
-	    lappend mlst %R  [string map $mlst [dict get $mcd TIME_FORMAT_24]]
-	    lappend mlst %r  [string map $mlst [dict get $mcd TIME_FORMAT_12]]
-	    lappend mlst %X  [string map $mlst [dict get $mcd TIME_FORMAT]]
-	    lappend mlst %EX [string map $mlst [dict get $mcd LOCALE_TIME_FORMAT]]
-	    lappend mlst %x  [string map $mlst [dict get $mcd DATE_FORMAT]]
-	    lappend mlst %Ex [string map $mlst [dict get $mcd LOCALE_DATE_FORMAT]]
-	    lappend mlst %c  [string map $mlst [dict get $mcd DATE_TIME_FORMAT]]
-	    lappend mlst %Ec [string map $mlst [dict get $mcd LOCALE_DATE_TIME_FORMAT]]
+#----------------------------------------------------------------------
+#
+# FormatStarDate --
+#
+#	Formats a date as a StarDate.
+#
+# Parameters:
+#	date - Dictionary containing 'year', 'dayOfYear', and
+#	       'localSeconds' fields.
+#
+# Results:
+#	Returns the given date formatted as a StarDate.
+#
+# Side effects:
+#	None.
+#
+# Jeff Hobbs put this in to support an atrocious pun about Tcl being
+# "Enterprise ready."  Now we're stuck with it.
+#
+#----------------------------------------------------------------------
 
-	    dict set LocaleFormats $locale MLST $mlst
-	}
+proc ::tcl::clock::FormatStarDate { date } {
+    variable Roddenberry
+
+    # Get day of year, zero based
+
+    set doy [expr { [dict get $date dayOfYear] - 1 }]
+
+    # Determine whether the year is a leap year
+
+    set lp [IsGregorianLeapYear $date]
+
+    # Convert day of year to a fractional year
+
+    if { $lp } {
+	set fractYear [expr { 1000 * $doy / 366 }]
+    } else {
+	set fractYear [expr { 1000 * $doy / 365 }]
+    }
+
+    # Put together the StarDate
+
+    return [::format "Stardate %02d%03d.%1d" \
+		[expr { [dict get $date year] - $Roddenberry }] \
+		$fractYear \
+		[expr { [dict get $date localSeconds] % 86400
+			/ ( 86400 / 10 ) }]]
+}
+
+#----------------------------------------------------------------------
+#
+# ParseStarDate --
+#
+#	Parses a StarDate
+#
+# Parameters:
+#	year - Year from the Roddenberry epoch
+#	fractYear - Fraction of a year specifiying the day of year.
+#	fractDay - Fraction of a day
+#
+# Results:
+#	Returns a count of seconds from the Posix epoch.
+#
+# Side effects:
+#	None.
+#
+# Jeff Hobbs put this in to support an atrocious pun about Tcl being
+# "Enterprise ready."  Now we're stuck with it.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::ParseStarDate { year fractYear fractDay } {
+    variable Roddenberry
+
+    # Build a tentative date from year and fraction.
+
+    set date [dict create \
+		  gregorian 1 \
+		  era CE \
+		  year [expr { $year + $Roddenberry }] \
+		  dayOfYear [expr { $fractYear * 365 / 1000 + 1 }]]
+    set date [GetJulianDayFromGregorianEraYearDay $date[set date {}]]
+
+    # Determine whether the given year is a leap year
+
+    set lp [IsGregorianLeapYear $date]
+
+    # Reconvert the fractional year according to whether the given year is a
+    # leap year
+
+    if { $lp } {
+	dict set date dayOfYear \
+	    [expr { $fractYear * 366 / 1000 + 1 }]
+    } else {
+	dict set date dayOfYear \
+	    [expr { $fractYear * 365 / 1000 + 1 }]
+    }
+    dict unset date julianDay
+    dict unset date gregorian
+    set date [GetJulianDayFromGregorianEraYearDay $date[set date {}]]
+
+    return [expr {
+	86400 * [dict get $date julianDay]
+	- 210866803200
+	+ ( 86400 / 10 ) * $fractDay
+    }]
+}
 
-	# translate copy of format (don't use format object here, because otherwise
-	# it can lose its internal representation (string map - convert to unicode)
-	set locfmt [string map $mlst [string range " $format" 1 end]]
+#----------------------------------------------------------------------
+#
+# ScanWide --
+#
+#	Scans a wide integer from an input
+#
+# Parameters:
+#	str - String containing a decimal wide integer
+#
+# Results:
+#	Returns the string as a pure wide integer.  Throws an error if the
+#	string is misformatted or out of range.
+#
+#----------------------------------------------------------------------
 
-	# cache it:
-	dict set LocaleFormats $locale $fmtkey $locfmt
+proc ::tcl::clock::ScanWide { str } {
+    set count [::scan $str {%ld %c} result junk]
+    if { $count != 1 } {
+	return -code error -errorcode [list CLOCK notAnInteger $str] \
+	    "\"$str\" is not an integer"
+    }
+    if { [incr result 0] != $str } {
+	return -code error -errorcode [list CLOCK integervalueTooLarge] \
+	    "integer value too large to represent"
     }
+    return $result
+}
 
-    # Save original format as long as possible, because of internal
-    # representation (performance).
-    # Note that in this case such format will be never localized (also
-    # using another locales). To prevent this return a duplicate (but
-    # it may be slower).
-    if {$locfmt eq $format} {
-        set locfmt $format
+#----------------------------------------------------------------------
+#
+# InterpretTwoDigitYear --
+#
+#	Given a date that contains only the year of the century, determines
+#	the target value of a two-digit year.
+#
+# Parameters:
+#	date - Dictionary containing fields of the date.
+#	baseTime - Base time relative to which the date is expressed.
+#	twoDigitField - Name of the field that stores the two-digit year.
+#			Default is 'yearOfCentury'
+#	fourDigitField - Name of the field that will receive the four-digit
+#	                 year.  Default is 'year'
+#
+# Results:
+#	Returns the dictionary augmented with the four-digit year, stored in
+#	the given key.
+#
+# Side effects:
+#	None.
+#
+# The current rule for interpreting a two-digit year is that the year shall be
+# between 1937 and 2037, thus staying within the range of a 32-bit signed
+# value for time.  This rule may change to a sliding window in future
+# versions, so the 'baseTime' parameter (which is currently ignored) is
+# provided in the procedure signature.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::InterpretTwoDigitYear { date baseTime
+					   { twoDigitField yearOfCentury }
+					   { fourDigitField year } } {
+    set yr [dict get $date $twoDigitField]
+    if { $yr <= 37 } {
+	dict set date $fourDigitField [expr { $yr + 2000 }]
+    } else {
+	dict set date $fourDigitField [expr { $yr + 1900 }]
     }
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
+# AssignBaseYear --
+#
+#	Places the number of the current year into a dictionary.
+#
+# Parameters:
+#	date - Dictionary value to update
+#	baseTime - Base time from which to extract the year, expressed
+#		   in seconds from the Posix epoch
+#	timezone - the time zone in which the date is being scanned
+#	changeover - the Julian Day on which the Gregorian calendar
+#		     was adopted in the target locale.
+#
+# Results:
+#	Returns the dictionary with the current year assigned.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AssignBaseYear { date baseTime timezone changeover } {
+    variable TZData
+
+    # Find the Julian Day Number corresponding to the base time, and
+    # find the Gregorian year corresponding to that Julian Day.
+
+    set date2 [GetDateFields $baseTime $TZData($timezone) $changeover]
+
+    # Store the converted year
+
+    dict set date era [dict get $date2 era]
+    dict set date year [dict get $date2 year]
+
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
+# AssignBaseIso8601Year --
+#
+#	Determines the base year in the ISO8601 fiscal calendar.
+#
+# Parameters:
+#	date - Dictionary containing the fields of the date that
+#	       is to be augmented with the base year.
+#	baseTime - Base time expressed in seconds from the Posix epoch.
+#	timeZone - Target time zone
+#	changeover - Julian Day of adoption of the Gregorian calendar in
+#		     the target locale.
+#
+# Results:
+#	Returns the given date with "iso8601Year" set to the
+#	base year.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AssignBaseIso8601Year {date baseTime timeZone changeover} {
+    variable TZData
+
+    # Find the Julian Day Number corresponding to the base time
+
+    set date2 [GetDateFields $baseTime $TZData($timeZone) $changeover]
+
+    # Calculate the ISO8601 date and transfer the year
+
+    dict set date era CE
+    dict set date iso8601Year [dict get $date2 iso8601Year]
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
+# AssignBaseMonth --
+#
+#	Places the number of the current year and month into a
+#	dictionary.
+#
+# Parameters:
+#	date - Dictionary value to update
+#	baseTime - Time from which the year and month are to be
+#	           obtained, expressed in seconds from the Posix epoch.
+#	timezone - Name of the desired time zone
+#	changeover - Julian Day on which the Gregorian calendar was adopted.
+#
+# Results:
+#	Returns the dictionary with the base year and month assigned.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AssignBaseMonth {date baseTime timezone changeover} {
+    variable TZData
+
+    # Find the year and month corresponding to the base time
+
+    set date2 [GetDateFields $baseTime $TZData($timezone) $changeover]
+    dict set date era [dict get $date2 era]
+    dict set date year [dict get $date2 year]
+    dict set date month [dict get $date2 month]
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
+# AssignBaseWeek --
+#
+#	Determines the base year and week in the ISO8601 fiscal calendar.
+#
+# Parameters:
+#	date - Dictionary containing the fields of the date that
+#	       is to be augmented with the base year and week.
+#	baseTime - Base time expressed in seconds from the Posix epoch.
+#	changeover - Julian Day on which the Gregorian calendar was adopted
+#		     in the target locale.
+#
+# Results:
+#	Returns the given date with "iso8601Year" set to the
+#	base year and "iso8601Week" to the week number.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AssignBaseWeek {date baseTime timeZone changeover} {
+    variable TZData
+
+    # Find the Julian Day Number corresponding to the base time
+
+    set date2 [GetDateFields $baseTime $TZData($timeZone) $changeover]
 
-    return $locfmt
+    # Calculate the ISO8601 date and transfer the year
+
+    dict set date era CE
+    dict set date iso8601Year [dict get $date2 iso8601Year]
+    dict set date iso8601Week [dict get $date2 iso8601Week]
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
+# AssignBaseJulianDay --
+#
+#	Determines the base day for a time-of-day conversion.
+#
+# Parameters:
+#	date - Dictionary that is to get the base day
+#	baseTime - Base time expressed in seconds from the Posix epoch
+#	changeover - Julian day on which the Gregorian calendar was
+#		     adpoted in the target locale.
+#
+# Results:
+#	Returns the given dictionary augmented with a 'julianDay' field
+#	that contains the base day.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AssignBaseJulianDay { date baseTime timeZone changeover } {
+    variable TZData
+
+    # Find the Julian Day Number corresponding to the base time
+
+    set date2 [GetDateFields $baseTime $TZData($timeZone) $changeover]
+    dict set date julianDay [dict get $date2 julianDay]
+
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
+# InterpretHMSP --
+#
+#	Interprets a time in the form "hh:mm:ss am".
+#
+# Parameters:
+#	date -- Dictionary containing "hourAMPM", "minute", "second"
+#	        and "amPmIndicator" fields.
+#
+# Results:
+#	Returns the number of seconds from local midnight.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::InterpretHMSP { date } {
+    set hr [dict get $date hourAMPM]
+    if { $hr == 12 } {
+	set hr 0
+    }
+    if { [dict get $date amPmIndicator] } {
+	incr hr 12
+    }
+    dict set date hour $hr
+    return [InterpretHMS $date[set date {}]]
+}
+
+#----------------------------------------------------------------------
+#
+# InterpretHMS --
+#
+#	Interprets a 24-hour time "hh:mm:ss"
+#
+# Parameters:
+#	date -- Dictionary containing the "hour", "minute" and "second"
+#	        fields.
+#
+# Results:
+#	Returns the given dictionary augmented with a "secondOfDay"
+#	field containing the number of seconds from local midnight.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::InterpretHMS { date } {
+    return [expr {
+	( [dict get $date hour] * 60
+	  + [dict get $date minute] ) * 60
+	+ [dict get $date second]
+    }]
 }
 
 #----------------------------------------------------------------------
@@ -898,12 +2975,13 @@ proc ::tcl::clock::LocalizeFormat { locale format {fmtkey {}} } {
 #	Returns the system time zone.
 #
 # Side effects:
-#	Stores the sustem time zone in engine configuration, since
-#	determining it may be an expensive process.
+#	Stores the sustem time zone in the 'CachedSystemTimeZone'
+#	variable, since determining it may be an expensive process.
 #
 #----------------------------------------------------------------------
 
 proc ::tcl::clock::GetSystemTimeZone {} {
+    variable CachedSystemTimeZone
     variable TimeZoneBad
 
     if {[set result [getenv TCL_TZ]] ne {}} {
@@ -912,33 +2990,61 @@ proc ::tcl::clock::GetSystemTimeZone {} {
 	set timezone $result
     }
     if {![info exists timezone]} {
-        # ask engine for the cached timezone:
-        set timezone [configure -system-tz]
-        if { $timezone ne "" } {
-            return $timezone
+        # Cache the time zone only if it was detected by one of the
+        # expensive methods.
+        if { [info exists CachedSystemTimeZone] } {
+            set timezone $CachedSystemTimeZone
+        } elseif { $::tcl_platform(platform) eq {windows} } {
+            set timezone [GuessWindowsTimeZone]
+        } elseif { [file exists /etc/localtime]
+                   && ![catch {ReadZoneinfoFile \
+                                   Tcl/Localtime /etc/localtime}] } {
+            set timezone :Tcl/Localtime
+        } else {
+            set timezone :localtime
         }
-	if { $::tcl_platform(platform) eq {windows} } {
-	    set timezone [GuessWindowsTimeZone]
-	} elseif { [file exists /etc/localtime]
-	           && ![catch {ReadZoneinfoFile \
-	                           Tcl/Localtime /etc/localtime}] } {
-	    set timezone :Tcl/Localtime
-	} else {
-	    set timezone :localtime
-	}
+	set CachedSystemTimeZone $timezone
     }
     if { ![dict exists $TimeZoneBad $timezone] } {
-	catch {set timezone [SetupTimeZone $timezone]}
+	dict set TimeZoneBad $timezone [catch {SetupTimeZone $timezone}]
     }
-
-    if { [dict exists $TimeZoneBad $timezone] } {
-	set timezone :localtime
+    if { [dict get $TimeZoneBad $timezone] } {
+	return :localtime
+    } else {
+	return $timezone
     }
+}
+
+#----------------------------------------------------------------------
+#
+# ConvertLegacyTimeZone --
+#
+#	Given an alphanumeric time zone identifier and the system time zone,
+#	convert the alphanumeric identifier to an unambiguous time zone.
+#
+# Parameters:
+#	tzname - Name of the time zone to convert
+#
+# Results:
+#	Returns a time zone name corresponding to tzname, but in an
+#	unambiguous form, generally +hhmm.
+#
+# This procedure is implemented primarily to allow the parsing of RFC822
+# date/time strings.  Processing a time zone name on input is not recommended
+# practice, because there is considerable room for ambiguity; for instance, is
+# BST Brazilian Standard Time, or British Summer Time?
+#
+#----------------------------------------------------------------------
 
-    # tell backend - current system timezone:
-    configure -system-tz $timezone
+proc ::tcl::clock::ConvertLegacyTimeZone { tzname } {
+    variable LegacyTimeZone
 
-    return $timezone
+    set tzname [string tolower $tzname]
+    if { ![dict exists $LegacyTimeZone $tzname] } {
+	return -code error -errorcode [list CLOCK badTZName $tzname] \
+	    "time zone \"$tzname\" not found"
+    }
+    return [dict get $LegacyTimeZone $tzname]
 }
 
 #----------------------------------------------------------------------
@@ -958,17 +3064,10 @@ proc ::tcl::clock::GetSystemTimeZone {} {
 #
 #----------------------------------------------------------------------
 
-proc ::tcl::clock::SetupTimeZone { timezone {alias {}} } {
+proc ::tcl::clock::SetupTimeZone { timezone } {
     variable TZData
 
     if {! [info exists TZData($timezone)] } {
-
-    	variable TimeZoneBad
-	if { [dict exists $TimeZoneBad $timezone] } {
-	    return -code error \
-		-errorcode [list CLOCK badTimeZone $timezone] \
-		"time zone \"$timezone\" not found"
-	}
 	variable MINWIDE
 	if { $timezone eq {:localtime} } {
 	    # Nothing to do, we'll convert using the localtime function
@@ -1006,7 +3105,6 @@ proc ::tcl::clock::SetupTimeZone { timezone {alias {}} } {
 		    LoadZoneinfoFile [string range $timezone 1 end]
 		}]
 	    } then {
-	    	dict set TimeZoneBad $timezone 1
 		return -code error \
 		    -errorcode [list CLOCK badTimeZone $timezone] \
 		    "time zone \"$timezone\" not found"
@@ -1018,43 +3116,25 @@ proc ::tcl::clock::SetupTimeZone { timezone {alias {}} } {
 		if { [lindex [dict get $opts -errorcode] 0] eq {CLOCK} } {
 		    dict unset opts -errorinfo
 		}
-		dict set TimeZoneBad $timezone 1
 		return -options $opts $data
 	    } else {
 		set TZData($timezone) $data
 	    }
 
 	} else {
-
-	    variable LegacyTimeZone
-
 	    # We couldn't parse this as a POSIX time zone.  Try again with a
 	    # time zone file - this time without a colon
 
 	    if { [catch { LoadTimeZoneFile $timezone }]
 		 && [catch { LoadZoneinfoFile $timezone } - opts] } {
-
-		# Check may be a legacy zone:
-
-		if { $alias eq {} && ![catch {
-		    set tzname [dict get $LegacyTimeZone [string tolower $timezone]]
-		}] } {
-		    set tzname [::tcl::clock::SetupTimeZone $tzname $timezone]
-		    set TZData($timezone) $TZData($tzname)
-		    # tell backend - timezone is initialized and return shared timezone object:
-		    return [configure -setup-tz $timezone]
-		}
-
 		dict unset opts -errorinfo
-		dict set TimeZoneBad $timezone 1
 		return -options $opts "time zone $timezone not found"
 	    }
 	    set TZData($timezone) $TZData(:$timezone)
 	}
     }
 
-    # tell backend - timezone is initialized and return shared timezone object:
-    configure -setup-tz $timezone
+    return
 }
 
 #----------------------------------------------------------------------
@@ -1125,12 +3205,12 @@ proc ::tcl::clock::GuessWindowsTimeZone {} {
     if { [dict exists $WinZoneInfo $data] } {
 	set tzname [dict get $WinZoneInfo $data]
 	if { ! [dict exists $TimeZoneBad $tzname] } {
-	    catch {set tzname [SetupTimeZone $tzname]}
+	    dict set TimeZoneBad $tzname [catch {SetupTimeZone $tzname}]
 	}
     } else {
 	set tzname {}
     }
-    if { $tzname eq {} || [dict exists $TimeZoneBad $tzname] } {
+    if { $tzname eq {} || [dict get $TimeZoneBad $tzname] } {
 	lassign $data \
 	    bias stdBias dstBias \
 	    stdYear stdMonth stdDayOfWeek stdDayOfMonth \
@@ -1857,6 +3937,43 @@ proc ::tcl::clock::DeterminePosixDSTTime { z bound y } {
 
 #----------------------------------------------------------------------
 #
+# GetLocaleEra --
+#
+#	Given local time expressed in seconds from the Posix epoch,
+#	determine localized era and year within the era.
+#
+# Parameters:
+#	date - Dictionary that must contain the keys, 'localSeconds',
+#	       whose value is expressed as the appropriate local time;
+#	       and 'year', whose value is the Gregorian year.
+#	etable - Value of the LOCALE_ERAS key in the message catalogue
+#	         for the target locale.
+#
+# Results:
+#	Returns the dictionary, augmented with the keys, 'localeEra' and
+#	'localeYear'.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::GetLocaleEra { date etable } {
+    set index [BSearch $etable [dict get $date localSeconds]]
+    if { $index < 0} {
+	dict set date localeEra \
+	    [::format %02d [expr { [dict get $date year] / 100 }]]
+	dict set date localeYear [expr {
+	    [dict get $date year] % 100
+	}]
+    } else {
+	dict set date localeEra [lindex $etable $index 1]
+	dict set date localeYear [expr {
+	    [dict get $date year] - [lindex $etable $index 2]
+	}]
+    }
+    return $date
+}
+
+#----------------------------------------------------------------------
+#
 # GetJulianDayFromEraYearDay --
 #
 #	Given a year, month and day on the Gregorian calendar, determines
@@ -2034,6 +4151,331 @@ proc ::tcl::clock::WeekdayOnOrBefore { weekday j } {
 
 #----------------------------------------------------------------------
 #
+# BSearch --
+#
+#	Service procedure that does binary search in several places inside the
+#	'clock' command.
+#
+# Parameters:
+#	list - List of lists, sorted in ascending order by the
+#	       first elements
+#	key - Value to search for
+#
+# Results:
+#	Returns the index of the greatest element in $list that is less than
+#	or equal to $key.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::BSearch { list key } {
+    if {[llength $list] == 0} {
+	return -1
+    }
+    if { $key < [lindex $list 0 0] } {
+	return -1
+    }
+
+    set l 0
+    set u [expr { [llength $list] - 1 }]
+
+    while { $l < $u } {
+	# At this point, we know that
+	#   $k >= [lindex $list $l 0]
+	#   Either $u == [llength $list] or else $k < [lindex $list $u+1 0]
+	# We find the midpoint of the interval {l,u} rounded UP, compare
+	# against it, and set l or u to maintain the invariant.  Note that the
+	# interval shrinks at each step, guaranteeing convergence.
+
+	set m [expr { ( $l + $u + 1 ) / 2 }]
+	if { $key >= [lindex $list $m 0] } {
+	    set l $m
+	} else {
+	    set u [expr { $m - 1 }]
+	}
+    }
+
+    return $l
+}
+
+#----------------------------------------------------------------------
+#
+# clock add --
+#
+#	Adds an offset to a given time.
+#
+# Syntax:
+#	clock add clockval ?count unit?... ?-option value?
+#
+# Parameters:
+#	clockval -- Starting time value
+#	count -- Amount of a unit of time to add
+#	unit -- Unit of time to add, must be one of:
+#			years year months month weeks week
+#			days day hours hour minutes minute
+#			seconds second
+#
+# Options:
+#	-gmt BOOLEAN
+#		(Deprecated) Flag synonymous with '-timezone :GMT'
+#	-timezone ZONE
+#		Name of the time zone in which calculations are to be done.
+#	-locale NAME
+#		Name of the locale in which calculations are to be done.
+#		Used to determine the Gregorian change date.
+#
+# Results:
+#	Returns the given time adjusted by the given offset(s) in
+#	order.
+#
+# Notes:
+#	It is possible that adding a number of months or years will adjust the
+#	day of the month as well.  For instance, the time at one month after
+#	31 January is either 28 or 29 February, because February has fewer
+#	than 31 days.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::add { clockval args } {
+    if { [llength $args] % 2 != 0 } {
+	set cmdName "clock add"
+	return -code error \
+	    -errorcode [list CLOCK wrongNumArgs] \
+	    "wrong \# args: should be\
+             \"$cmdName clockval ?number units?...\
+             ?-gmt boolean? ?-locale LOCALE? ?-timezone ZONE?\""
+    }
+    if { [catch { expr {wide($clockval)} } result] } {
+	return -code error $result
+    }
+
+    set offsets {}
+    set gmt 0
+    set locale c
+    set timezone [GetSystemTimeZone]
+
+    foreach { a b } $args {
+	if { [string is integer -strict $a] } {
+	    lappend offsets $a $b
+	} else {
+	    switch -exact -- $a {
+		-g - -gm - -gmt {
+		    set gmt $b
+		}
+		-l - -lo - -loc - -loca - -local - -locale {
+		    set locale [string tolower $b]
+		}
+		-t - -ti - -tim - -time - -timez - -timezo - -timezon -
+		-timezone {
+		    set timezone $b
+		}
+		default {
+		    throw [list CLOCK badOption $a] \
+			"bad option \"$a\",\
+                         must be -gmt, -locale or -timezone"
+		}
+	    }
+	}
+    }
+
+    # Check options for validity
+
+    if { [info exists saw(-gmt)] && [info exists saw(-timezone)] } {
+	return -code error \
+	    -errorcode [list CLOCK gmtWithTimezone] \
+	    "cannot use -gmt and -timezone in same call"
+    }
+    if { [catch { expr { wide($clockval) } } result] } {
+	return -code error "expected integer but got \"$clockval\""
+    }
+    if { ![string is boolean -strict $gmt] } {
+	return -code error "expected boolean value but got \"$gmt\""
+    } elseif { $gmt } {
+	set timezone :GMT
+    }
+
+    EnterLocale $locale
+
+    set changeover [mc GREGORIAN_CHANGE_DATE]
+
+    if {[catch {SetupTimeZone $timezone} retval opts]} {
+	dict unset opts -errorinfo
+	return -options $opts $retval
+    }
+
+    try {
+	foreach { quantity unit } $offsets {
+	    switch -exact -- $unit {
+		years - year {
+		    set clockval [AddMonths [expr { 12 * $quantity }] \
+			    $clockval $timezone $changeover]
+		}
+		months - month {
+		    set clockval [AddMonths $quantity $clockval $timezone \
+			    $changeover]
+		}
+
+		weeks - week {
+		    set clockval [AddDays [expr { 7 * $quantity }] \
+			    $clockval $timezone $changeover]
+		}
+		days - day {
+		    set clockval [AddDays $quantity $clockval $timezone \
+			    $changeover]
+		}
+
+		hours - hour {
+		    set clockval [expr { 3600 * $quantity + $clockval }]
+		}
+		minutes - minute {
+		    set clockval [expr { 60 * $quantity + $clockval }]
+		}
+		seconds - second {
+		    set clockval [expr { $quantity + $clockval }]
+		}
+
+		default {
+		    throw [list CLOCK badUnit $unit] \
+			"unknown unit \"$unit\", must be \
+                        years, months, weeks, days, hours, minutes or seconds"
+		}
+	    }
+	}
+	return $clockval
+    } trap CLOCK {result opts} {
+	# Conceal the innards of [clock] when it's an expected error
+	dict unset opts -errorinfo
+	return -options $opts $result
+    }
+}
+
+#----------------------------------------------------------------------
+#
+# AddMonths --
+#
+#	Add a given number of months to a given clock value in a given
+#	time zone.
+#
+# Parameters:
+#	months - Number of months to add (may be negative)
+#	clockval - Seconds since the epoch before the operation
+#	timezone - Time zone in which the operation is to be performed
+#
+# Results:
+#	Returns the new clock value as a number of seconds since
+#	the epoch.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AddMonths { months clockval timezone changeover } {
+    variable DaysInRomanMonthInCommonYear
+    variable DaysInRomanMonthInLeapYear
+    variable TZData
+
+    # Convert the time to year, month, day, and fraction of day.
+
+    set date [GetDateFields $clockval $TZData($timezone) $changeover]
+    dict set date secondOfDay [expr {
+	[dict get $date localSeconds] % 86400
+    }]
+    dict set date tzName $timezone
+
+    # Add the requisite number of months
+
+    set m [dict get $date month]
+    incr m $months
+    incr m -1
+    set delta [expr { $m / 12 }]
+    set mm [expr { $m % 12 }]
+    dict set date month [expr { $mm + 1 }]
+    dict incr date year $delta
+
+    # If the date doesn't exist in the current month, repair it
+
+    if { [IsGregorianLeapYear $date] } {
+	set hath [lindex $DaysInRomanMonthInLeapYear $mm]
+    } else {
+	set hath [lindex $DaysInRomanMonthInCommonYear $mm]
+    }
+    if { [dict get $date dayOfMonth] > $hath } {
+	dict set date dayOfMonth $hath
+    }
+
+    # Reconvert to a number of seconds
+
+    set date [GetJulianDayFromEraYearMonthDay \
+		  $date[set date {}]\
+		  $changeover]
+    dict set date localSeconds [expr {
+	-210866803200
+	+ ( 86400 * wide([dict get $date julianDay]) )
+	+ [dict get $date secondOfDay]
+    }]
+    set date [ConvertLocalToUTC $date[set date {}] $TZData($timezone) \
+		 $changeover]
+
+    return [dict get $date seconds]
+
+}
+
+#----------------------------------------------------------------------
+#
+# AddDays --
+#
+#	Add a given number of days to a given clock value in a given time
+#	zone.
+#
+# Parameters:
+#	days - Number of days to add (may be negative)
+#	clockval - Seconds since the epoch before the operation
+#	timezone - Time zone in which the operation is to be performed
+#	changeover - Julian Day on which the Gregorian calendar was adopted
+#		     in the target locale.
+#
+# Results:
+#	Returns the new clock value as a number of seconds since the epoch.
+#
+# Side effects:
+#	None.
+#
+#----------------------------------------------------------------------
+
+proc ::tcl::clock::AddDays { days clockval timezone changeover } {
+    variable TZData
+
+    # Convert the time to Julian Day
+
+    set date [GetDateFields $clockval $TZData($timezone) $changeover]
+    dict set date secondOfDay [expr {
+	[dict get $date localSeconds] % 86400
+    }]
+    dict set date tzName $timezone
+
+    # Add the requisite number of days
+
+    dict incr date julianDay $days
+
+    # Reconvert to a number of seconds
+
+    dict set date localSeconds [expr {
+	-210866803200
+	+ ( 86400 * wide([dict get $date julianDay]) )
+	+ [dict get $date secondOfDay]
+    }]
+    set date [ConvertLocalToUTC $date[set date {}] $TZData($timezone) \
+		  $changeover]
+
+    return [dict get $date seconds]
+
+}
+
+#----------------------------------------------------------------------
+#
 # ChangeCurrentLocale --
 #
 #        The global locale was changed within msgcat.
@@ -2051,11 +4493,10 @@ proc ::tcl::clock::WeekdayOnOrBefore { weekday j } {
 #----------------------------------------------------------------------
 
 proc ::tcl::clock::ChangeCurrentLocale {args} {
-
-    configure -default-locale [lindex $args 0]
-
     variable FormatProc
     variable LocaleNumeralCache
+    variable CachedSystemTimeZone
+    variable TimeZoneBad
 
     foreach p [info procs [namespace current]::scanproc'*'current] {
         rename $p {}
@@ -2087,17 +4528,10 @@ proc ::tcl::clock::ChangeCurrentLocale {args} {
 
 proc ::tcl::clock::ClearCaches {} {
     variable FormatProc
-    variable LocaleFormats
     variable LocaleNumeralCache
-    variable mcMergedCat
+    variable CachedSystemTimeZone
     variable TimeZoneBad
 
-    # tell backend - should invalidate:
-    configure -clear
-
-    # clear msgcat cache:
-    set mcMergedCat [dict create]
-
     foreach p [info procs [namespace current]::scanproc'*] {
 	rename $p {}
     }
@@ -2105,9 +4539,9 @@ proc ::tcl::clock::ClearCaches {} {
 	rename $p {}
     }
 
-    unset -nocomplain FormatProc
-    set LocaleFormats {}
+    catch {unset FormatProc}
     set LocaleNumeralCache {}
+    catch {unset CachedSystemTimeZone}
     set TimeZoneBad {}
     InitTZData
 }
diff --git a/library/init.tcl b/library/init.tcl
index dba73b0..5cedd14 100644
--- a/library/init.tcl
+++ b/library/init.tcl
@@ -45,7 +45,6 @@ if {![info exists auto_path]} {
 	set auto_path ""
     }
 }
-
 namespace eval tcl {
     variable Dir
     foreach Dir [list $::tcl_library [file dirname $::tcl_library]] {
@@ -67,12 +66,12 @@ namespace eval tcl {
     }
 
     if {![interp issafe]} {
-	variable Path [encoding dirs]
-	set Dir [file join $::tcl_library encoding]
-	if {$Dir ni $Path} {
+        variable Path [encoding dirs]
+        set Dir [file join $::tcl_library encoding]
+        if {$Dir ni $Path} {
 	    lappend Path $Dir
 	    encoding dirs $Path
-	}
+        }
     }
 
     # TIP #255 min and max functions
@@ -158,17 +157,6 @@ if {(![interp issafe]) && ($tcl_platform(platform) eq "windows")} {
 if {[interp issafe]} {
     package unknown {::tcl::tm::UnknownHandler ::tclPkgUnknown}
 } else {
-    # Default known auto_index (avoid loading auto index implicit after interp create):
-
-    array set ::auto_index {
-	::tcl::tm::UnknownHandler {source [info library]/tm.tcl}
-	::tclPkgUnknown {source [info library]/package.tcl}
-	::history {source [info library]/history.tcl}
-    }
-
-    # The newest possibility to load whole namespace:
-    array set ::auto_index_ns {}
-
     # Set up search for Tcl Modules (TIP #189).
     # and setup platform specific unknown package handlers
     if {$tcl_platform(os) eq "Darwin"
@@ -181,21 +169,22 @@ if {[interp issafe]} {
 
     # Set up the 'clock' ensemble
 
-    proc clock args {
-	set cmdmap [dict create]
-	foreach cmd {add clicks format microseconds milliseconds scan seconds configure} {
-	    dict set cmdmap $cmd ::tcl::clock::$cmd
+    namespace eval ::tcl::clock [list variable TclLibDir $::tcl_library]
+
+    proc ::tcl::initClock {} {
+	# Auto-loading stubs for 'clock.tcl'
+
+	foreach cmd {add format scan} {
+	    proc ::tcl::clock::$cmd args {
+		variable TclLibDir
+		source -encoding utf-8 [file join $TclLibDir clock.tcl]
+		return [uplevel 1 [info level 0]]
+	    }
 	}
-	namespace inscope ::tcl::clock [list namespace ensemble create -command \
-	    [uplevel 1 [list ::namespace origin [::lindex [info level 0] 0]]] \
-	    -map $cmdmap -compile 1]
 
-	uplevel 1 [info level 0]
+	rename ::tcl::initClock {}
     }
-    # Auto-loading stubs for 'clock.tcl'
-    set ::auto_index_ns(::tcl::clock) {::namespace inscope ::tcl::clock {
-	::source -encoding utf-8 [::file join [info library] clock.tcl]
-    }}
+    ::tcl::initClock
 }
 
 # Conditionalize for presence of exec.
@@ -423,22 +412,18 @@ proc unknown args {
 #                       for instance. If not given, namespace current is used.
 
 proc auto_load {cmd {namespace {}}} {
-    global auto_index auto_index_ns auto_path
+    global auto_index auto_path
 
-    # qualify names:
     if {$namespace eq ""} {
 	set namespace [uplevel 1 [list ::namespace current]]
     }
     set nameList [auto_qualify $cmd $namespace]
     # workaround non canonical auto_index entries that might be around
     # from older auto_mkindex versions
-    if {$cmd ni $nameList} {lappend nameList $cmd}
-
-    # try to load (and create sub-cmd handler "_sub_load_cmd" for further usage):
-    foreach name $nameList [set _sub_load_cmd {
-    	# via auto_index:
+    lappend nameList $cmd
+    foreach name $nameList {
 	if {[info exists auto_index($name)]} {
-	    namespace inscope :: $auto_index($name)
+	    namespace eval :: $auto_index($name)
 	    # There's a couple of ways to look for a command of a given
 	    # name.  One is to use
 	    #    info commands $name
@@ -450,31 +435,22 @@ proc auto_load {cmd {namespace {}}} {
 		return 1
 	    }
 	}
-	# via auto_index_ns - resolver for the whole namespace loaders
-	if {[set ns [::namespace qualifiers $name]] ni {"" "::"} &&
-	    [info exists auto_index_ns($ns)]
-	} {
-	    # remove handler before loading (prevents several self-recursion cases):
-	    set ldr $auto_index_ns($ns); unset auto_index_ns($ns)
-	    namespace inscope :: $ldr
-	    # if got it:
-	    if {[namespace which -command $name] ne ""} {
-		return 1
-	    }
-	}
-    }]
-
-    # load auto_index if possible:
+    }
     if {![info exists auto_path]} {
 	return 0
     }
+
     if {![auto_load_index]} {
 	return 0
     }
-
-    # try again (something new could be loaded):
-    foreach name $nameList $_sub_load_cmd
-
+    foreach name $nameList {
+	if {[info exists auto_index($name)]} {
+	    namespace eval :: $auto_index($name)
+	    if {[namespace which -command $name] ne ""} {
+		return 1
+	    }
+	}
+    }
     return 0
 }
 
@@ -637,12 +613,12 @@ proc auto_import {pattern} {
     auto_load_index
 
     foreach pattern $patternList {
-	foreach name [array names auto_index $pattern] {
-	    if {([namespace which -command $name] eq "")
+        foreach name [array names auto_index $pattern] {
+            if {([namespace which -command $name] eq "")
 		    && ([namespace qualifiers $pattern] eq [namespace qualifiers $name])} {
-		namespace inscope :: $auto_index($name)
-	    }
-	}
+                namespace eval :: $auto_index($name)
+            }
+        }
     }
 }