NAME
    File::Wildcard - Enhanced glob processing

SYNOPSIS
      use File::Wildcard;
      my $foo = File::Wildcard->new(path => "/home/me///core");
      while (my $file = $foo->next) {
         unlink $file;
      }
  
DESCRIPTION
    When looking at how various operating systems do filename wildcard
    expansion (globbing), VMS has a nice syntax which allows expansion and
    searching of whole directory trees. It would be nice if other operating
    systems had something like this built in. The best Unix can manage is
    through the utility program "find".

    This module provides this facility to Perl. Whereas native VMS syntax
    uses the ellipsis "...", this will not fit in with POSIX filenames, as
    ... is a valid (though somewhat strange) filename. Instead, the
    construct "///" is used as this cannot syntactically be part of a
    filename, as you do not get three concurrent filename separators with
    nothing between (three slashes are used to avoid confusion with
    //node/path/name syntax).

    You don't have to use this syntax, as you can do the splitting yourself
    and pass in an arrayref as your path.

    The module also forms a regular expression for the whole of the wildcard
    string, and binds a series of back references ($1, $2 etc.) which are
    available to construct new filenames.

  new
    "File::Wildcard-"new( $wildcard, [,option => value,...]);>

      my $foo = File::Wildcard->new( path => "/home/me///core");
      my $srcfnd = File::Wildcard->new( path => "src///*.cpp",
                   match => qr(^src/(.*?)\.cpp$),
                   derive => ['src/$1.o','src/$1.hpp']);

    This is the constructor for File::Wildcard objects. At a simple level,
    pass a single wildcard string as a path.

    For more complicated operations, you can supply your own match regexp,
    or use the derive option to specify regular expression captures to form
    the basis of other filenames that are constructed for you.

    The $srcfnd example gives you object files and header files
    corresponding to C++ source files.

    Here are the options that are available:

    "path"
        This is the input parameter that specifies the range of files that
        will be looked at. This is a glob spec which can also contain the
        ellipsis '///' (it could contain more than one ellipsis, but the
        benefit of this is questionable, and multiple ellipsi would cause a
        performance hit).

        Note that the path can be relative or absolute. new will do the
        right thing, working out that a path starting with '/' is absolute.
        In order to recurse from the current directory downwards, specify
        './//foo'.

        As an alternative, you can supply an arrayref with the path
        constituents already split. If you do this, you need to tell new if
        the path is absolute. Include an empty string for an ellipsis. For
        example:

          'foo///bar/*.c' is equivalent to ['foo','','bar','*.c']

        You can also construct a File::Wildcard without a path. A call to
        next will return undef, but paths can be added using the append and
        prepend methods.

    "absolute"
        This is ignored unless you are using a pre split path. If you are
        passing a string as the path, new will work out whether the path is
        absolute or relative. Pass a true value for absolute paths.

        If your original filespec started with '/' before you split it,
        specify absolute => 1. absolute is not required for Windows if the
        path contains a drive specification, e.g. C:/foo/bar.

    "case_insensitive"
        By default, the module will use Filesys::Type to determine whether
        the file system of your wildcard is defined. This is an optional
        module (see Module::Optional), and File::Wildcard will guess at case
        sensitivity based on your operating system. This will not always be
        correct, as the file system might be VFAT mounted on Linux or ODS-5
        on VMS.

        Specifying the option "case_insensitive" explicitly forces this
        behaviour on the wildcard.

        Note that File::Wildcard will use the file system of the current
        working directory if the path is not absolute. If the path is
        absolute, you should specify the case_sensitivity option explicitly.

    "match"
        Optional. If you do not specify a regexp, you get all the files that
        match the glob; in addition, new will set up a regexp for you, to
        provide a capture for each wildcard used in the path.

        If you do provide a match parameter, this will be used instead, and
        will filter the results.

    "derive"
        Supply an arrayref with a list of derived filenames, which will be
        constructed for each matching file. This causes next to return an
        arrayref instead of a scalar.

    "follow"
        If given a true value indicates that symbolic links are to be
        followed. Otherwise, the symbolic link target itself is presented,
        but the ellipsis will not traverse the link.

        This module detects a looping symlink that points to a directory
        higher up, and will only present the tree once.

    "ellipsis_order"
        This can take one of the following values: normal, breadth-first,
        inside-out. The default option is normal. This controls how
        File::Wildcard handles the ellipsis. The default is a normal depth
        first search, presenting the name of each containing directory
        before the contents.

        The inside-out order presents the contents of directories first
        before the directory, which is useful when you want to remove files
        and directories (all O/S require directories to be empty before
        rmdir will work). See t/03_absolute.t as this uses inside-out order
        to tidy up after the test.

        Breadth-first is rarely needed (but I do have an application for
        it). Here, the whole directory contents is presented before
        traversing any subdirectories.

        Consider the following tree: a/ a/bar/ a/bar/drink a/foo/ a/foo/lish

        breadth-first will give the following order: qw(a/ a/bar/ a/foo/
        a/bar/drink a/foo/lish). normal gives the order in which the files
        are listed. inside-out gives the following: qw(a/bar/drink a/bar/
        a/foo/lish a/foo/ a/).

    "sort"
        By default, globbing returns the list of files in the order in which
        they are returned by the dirhandle (internally). If you specify sort
        => 1, the files are sorted into ASCII sequence (case insensitively
        if we are operating that way). If you specify a CODEREF, this will
        be used as a comparison routine. Note that this takes its operands
        in @_, not in $a and $b.

    "debug" and "debug_output"
        You can enable a trace of the internal states of File::Wildcard by
        setting debug to a true value. Set debug_output to an open
        filehandle to get the trace in a file. If you are submitting bug
        reports for File::Wildcard, attaching debug trace files would be
        very useful.

        debug_output defaults to STDERR.

  match
      my $foo_re = $foo->match;
      $foo->match('bar/core');

    This is a get and set method that gives access to the match regexp that
    the File::Wildcard object is using. It is possible to change the regex
    on the fly in the middle of a search (though I don't know why anyone
    would want to do this).

  append
      $foo->append(path => '/home/me///*.tmp');

    appends a path to an object's todo list. This will be globbed after the
    object has finished processing the existing wildcards.

  prepend
      $srcfnd->prepend(path => $include_file);

    This is similar to append, but prepends the path to the todo list. In
    other words, the current wildcard operation is interrupted to serve the
    new path, then the previous wildcard operation is resumed when this is
    exhausted.

  next
      while (my $core = $foo->next) {
          unlink $core;
      }
      my ($src,$obj,$hdr) = @{$srcfnd->next};

    The "next" method is an iterator, which returns successive files.
    Returns matching files if there was no derive option passed to new. If
    there was a derive option, returns an arrayref containing the matching
    filespec and all derived filespecs. The derived filespecs do not have to
    exist.

    Note that "next" maintains an internal cursor, which retains context and
    state information. Beware if the contents of directories are changing
    while you are iterating with next; you may get unpredictable results. If
    you are intending to change the contents of the directories you are
    scanning (with unlink or rename), you are better off deferring this
    operation until you have processed the whole tree. For the pending
    delete or rename operations, you could always use another File::Wildcard
    object - see the spike example below:

  all
      my @cores = $foo->all;

    "all" returns an array of matching files, in the simple case. Returns an
    array of arrays if you are constructing new filenames, like the $srcfnd
    example.

    Beware of the performance and memory implications of using "all". The
    method will not return until it has read the entire directory tree. Use
    of the "all" method is not recommended for traversing large directory
    trees and whole file systems. Consider coding the traversal using the
    iterator "next" instead.

  reset
    "reset" causes the wildcard context to be set to re-read the first
    filename again. Note that this will cause directory contents to be
    re-read.

    Note also that this will cause the path to revert to the original path
    specified to new. Any additional paths appended or prepended will be
    forgotten.

  close
    Release all directory handles associated with the File::Wildcard object.
    An object that has been closed will be garbage collected once it goes
    out of scope. Wildcards that have been exhausted are automatically
    closed, (i.e. "all" was used, or c<next> returned undef).

    Subsequent calls to "next" will return undef. It is possible to call
    "reset" after "close" on the same File::Wildcard object, which will
    cause it to be reopened.

EXAMPLES
    * The spike
          my $todo = File::Wildcard->new;

          ...

          $todo->append(path => $file);

          ...

          while (my $file = $todo->next) {
          ...
          }

        You can use an empty wildcard to store a list of filenames for later
        processing. The order in which they will be seen depends on whether
        append or prepend is used.

    * Shell style globbing
          my $wc_args = File::Wildcard->new;

          $wc_args->append(path => $_) for @ARGV;

          while ($wc_args->next) {
          ...
          }

        On Unix, file wildcards on the command line are globbed by the shell
        before perl sees them, unless the wildcards are escaped or quoted.
        This is not true of other operating systems. MS-DOS does no globbing
        at all for example.

        File::Wildcard gives you the bonus of elliptic globbing with '///'.

CAVEAT
    This module takes POSIX filenames, which use forward slash '/' as a path
    separator. All operating systems that run Perl can manage this type of
    path. The module is not designed to work with native file specs. If you
    want to write code that is portable, convert native filespecs to the
    POSIX form. There is of course no difference on Unix platforms.

BUGS
    Please report bugs to http://rt.cpan.org

AUTHOR
            Ivor Williams
            ivorw-file-wildcard at xemaps.com

COPYRIGHT
    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself.

    The full text of the license can be found in the LICENSE file included
    with this module.

SEE ALSO
    glob(3), File::Find, File::Find::Rule.

