Open Mash Cross Reference
mash/tcl/mb/utils.tcl

   # utils.tcl --
   #
   #       FIXME: This file needs a description here.
   #
   # Copyright (c) 1993-2002 The Regents of the University of California.
   # All rights reserved.
   #
   # Redistribution and use in source and binary forms, with or without
   # modification, are permitted provided that the following conditions are met:
  #
  # A. Redistributions of source code must retain the above copyright notice,
  #    this list of conditions and the following disclaimer.
  # B. Redistributions in binary form must reproduce the above copyright notice,
  #    this list of conditions and the following disclaimer in the documentation
  #    and/or other materials provided with the distribution.
  # C. Neither the names of the copyright holders nor the names of its
  #    contributors may be used to endorse or promote products derived from this
  #    software without specific prior written permission.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
  # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  # ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR
  # ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  
  package provide mb_utils
  
  #
  # if old is found in list, replace it by new
  # if new is {}, old is deleted.
  #
  proc lsubst {list old new} {
      set ix [lsearch -exact $list $old]
      if {$ix >= 0} {
              if {$new!={}} {
                      return [lreplace $list $ix $ix $new]
              } else {
                      return [lreplace $list $ix $ix]
              }
      }
  }
  
  # we abstract this so that someday when can move this to C/C++
  proc removeFirst {varName} {
          upvar $varName l
          set f [lindex $l 0]
          set l [lrange $l 1 end]
          return $f
  }
  
  # experimental superclass for functions that allows callbacks
  Class Callback
  
  # does nothing
  Callback instproc init {} {
  }
  
  # register a callback for event
  # the callback will be executed like: eval $cmd $args
  Callback instproc add_callback {event cmd} {
          $self instvar callbacks_
          lappend callbacks_($event) $cmd
  }
  
  #
  # call a callback on event,
  # if there is no such callback, nothing is executed
  # otherwise a callback is issued for each registered callback
  #
  Callback instproc callback {event args} {
          $self instvar callbacks_
          if [info exists callbacks_($event)] {
                  foreach cmd $callbacks_($event) {
                          puts "callback: [concat $cmd $args]"
                          uplevel #0 $cmd $args
                  }
          }
  }