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fileutil_traverse(3tcl) file utilities fileutil_traverse(3tcl)
 


NAME

fileutil_traverse - Iterative directory traversal

SYNOPSIS

package require Tcl 8.3


package require fileutil::traverse ?0.4.3?


package require fileutil 


package require control 


::fileutil::traverse ?objectName? path ?option
  value...?


$traverser command ?arg arg ...?


$traverser files


$traverser foreach filevar script


$traverser next filevar





 


DESCRIPTION

This package provides objects for the programmable traversal of directory
  hierarchies. The main command exported by the package is:


  
::fileutil::traverse ?objectName? path ?option
    value...?

  
The command creates a new traversal object with an associated global Tcl
      command whose name is objectName. This command may be used to
      invoke various operations on the traverser. If the string %AUTO% is
      used as the objectName then a unique name will be generated by the
      package itself.
    

    Regarding the recognized options see section OPTIONS. Note that all
      these options can be set only during the creation of the traversal object.
      Changing them later is not possible and causes errors to be thrown if
      attempted.
    

    The object command has the following general form:







  
$traverser command ?arg arg ...?

  
Command and its arguments determine the exact behavior of
      the object.







The following commands are possible for traversal objects:


  
$traverser files

  
This method is the most highlevel one provided by traversal objects. When
      invoked it returns a list containing the names of all files and
      directories matching the current configuration of the traverser.





  
$traverser foreach filevar script

  
The highlevel files method (see above) is based on this mid-level
      method. When invoked it finds all files and directories matching per the
      current configuration and executes the script for each path. The
      current path under consideration is stored in the variable named by
      filevar. Both variable and script live / are executed in the
      context of the caller of the method. In the method files the script
      simply saves the found paths into the list to return.





  
$traverser next filevar

  
This is the lowest possible interface to the traverser, the core all
      higher methods are built on. When invoked it returns a boolean value
      indicating whether it found a path matching the current configuration (
      True), or not (False). If a path was found it is stored into
      the variable named by filevar, in the context of the caller. The
      foreach method simply calls this method in a loop until it returned
      False. This method is exposed so that we are also able to
      incrementally traverse a directory hierarchy in an event-based
    manner.




OPTIONS



  
-prefilter command_prefix

  
This callback is executed for directories. Its result determines if the
      traverser recurses into the directory or not. The default is to always
      recurse into all directories. The callback is invoked with a single
      argument, the absolute path of the directory, and has to return a
      boolean value, True when the directory passes the filter, and
      False if not.





  
-filter command_prefix

  
This callback is executed for all paths. Its result determines if the
      current path is a valid result, and returned by next. The default
      is to accept all paths as valid. The callback is invoked with a single
      argument, the absolute path to check, and has to return a boolean
      value, True when the path passes the filter, and False if
      not.





  
-errorcmd command_prefix

  
This callback is executed for all paths the traverser has trouble with.
      Like being unable to change into them, get their status, etc. The default
      is to ignore any such problems. The callback is invoked with a two
      arguments, the absolute path for which the error occured, and the
      error message. Errors thrown by the filter callbacks are handled through
      this callback too. Errors thrown by the error callback itself are not
      caught and ignored, but allowed to pass to the caller, i.e. however
      invoked the next. Any other results from the callback are
    ignored.




BUGS, IDEAS, FEEDBACK

This document, and the package it describes, will undoubtedly contain bugs and
  other problems. Please report such in the category fileutil of the
  Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please also
  report any ideas for enhancements you may have for either package and/or
  documentation.

KEYWORDS

directory traversal, traversal

CATEGORY

Programming tools



  

    0.4.3
    tcllib