fileutil_traverse(n) file utilities fileutil_traverse(n) ______________________________________________________________________________
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 direc-
tory 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 direc-
tory, 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 trou-
ble with. Like being unable to change into them, get their sta-
tus, etc. The default is to ignore any such problems. The call-
back 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://source-
forge.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)
Mac OS X 10.8 - Generated Sat Sep 15 06:10:53 CDT 2012