fileutil_traverse(n) file utilities fileutil_traverse(n)
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NAME
fileutil_traverse - Iterative directory traversal
SYNOPSIS
package require Tcl 8.3
package require fileutil::traverse ?0.4.1?
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
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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 traver-
sal 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 SF Trackers [http://sourceforge.net/tracker/?group_id=12883]. Please also report any ideas for enhancements you may have for
either package and/or documentation.
KEYWORDS
directory traversal, traversal
CATEGORY
Programming tools
fileutil 0.4.1 fileutil_traverse(n)