[MJ] - The following script adds the ''<Control-.>'' binding to text or entry widgets which allows entry of [Unicode] characters directly.

 package require Tcl 8.5
 text .t
 entry .e
 pack .t
 pack .e

 # enable functionality by adding the UnicodeEntry tag to the bindtags
 bindtags .t [list .t UnicodeEntry Text . all]
 bindtags .e [list .e UnicodeEntry Entry . all]


 variable uc_keys

 proc enable_unicode_entry {widget} {
      variable uc_keys
      set uc_keys($widget) {}
 }

 proc disable_unicode_entry {widget} {
      variable uc_keys
      unset -nocomplain uc_keys($widget)
 }

 proc handle_uc_key {widget key} {
      variable uc_keys
      if {![info exists uc_keys($widget)]} {
         return
      }
     
      upvar 0 uc_keys($widget) keys
      switch -nocase -regexp -- $key {
	{[0-9A-F]} {
	               append keys $key
	               if {[string length $keys] >= 4} {
		           $widget insert insert [subst \\u$keys]
                           disable_unicode_entry $widget
                       }
	               return -code break
	           }
	default    {
		       $widget insert insert $keys
                       disable_unicode_entry $widget
	           }      
        }		
 }

 bind UnicodeEntry <Control-.> {
	enable_unicode_entry %W
 }

 bind UnicodeEntry <Key> [list handle_uc_key %W %A]


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See also: [KHIM]