Fortune - read and write fortune (strfile) databases
# input
$ffile = new Fortune ($base_filename);
$ffile->read_header ();
$num_fortunes = $ffile->num_fortunes ();
$fortune = $ffile->read_fortune ($num);
$fortune = $ffile->get_random_fortune ();
# create header file from data file -- NOT IMPLEMENTED YET
$ffile = new Fortune ($base_filename);
$ffile->write_header ();
# write to data file -- NOT IMPLEMENTED YET
$ffile = new Fortune (">>$base_filename");
$ffile->write_fortune ($fortune);
The fortune program is a small but important part of the Unix
culture, and this module aims to provide support for its "fortune
cookie" databases to Perl programmers. For efficiency, all versions of
fortune rely on a binary header consisting mainly of offsets into the
fortune file proper. Modern versions of fortune keep this header in a
separate file, and this is the style adopted by the Fortune module;
the older style of munging the header and data into one large "compiled"
file is not (currently) supported.
Using the Fortune module makes it trivial to write a simplified
version of the fortune program:
# trivial 'fortune' progam my $fortune_filename = $ARGV[0]; my $fortune_file = new Fortune ($fortune_filename); $fortune_file->read_header (); my $fortune = $fortune_file->get_random_fortune (); print $fortune;
This can be compressed considerably:
print new Fortune ($ARGV[0])->read_header()->get_random_fortune();
Of course, this doesn't provide all of fortune's interesting
features, such as parallel databases of offensive fortunes, selection of
long or short fortunes, dealing with multiple fortune files, etc. If
you want fortune, use it -- but if you just want a simple Perl
interface to its data files, the Fortune module is for you.
Currently, the Fortune module does not support writing fortune
databases. If it did, writing a simplified strfile (the program that
processes a fortune database to create the header file) would also be
trivial:
# trivial (and hypothetical) 'strfile' program my $fortune_filename = @ARGV[0]; my $fortune_file = new Fortune ($fortune_filename); $fortune_file->write_header ();
Note that the header filename is assumed to be just the name of the main
fortune database, with ".dat" appended. You can supply an alternate
header filename to the constructor, new(), if you wish.
Opens a fortune cookie database. FILE is the name of the data file to
open, and HEADER_FILE (if given) the name of the header file that
contains (or will contain) meta-data about the fortune database. If
HEADER_FILE is not given, it defaults to FILE with ".dat" appended.
The data file is opened via open_file(), which dies if the file
cannot be opened. The header file is not opened, whether you supply
its filename or not -- after all, it might not exist yet. Rather, you
must explicitly call read_header() or write_header() as
appropriate.
Opens the fortune file whose name was supplied to the constructor. Dies on failure.
Closes the fortune file if it's open; does nothing otherwise.
Reads the header file associated with this fortune database. The name
of the header file is determined by the constructor new: either it is
based on the name of the data file, or supplied by the caller.
If the header file does not exist, this function calls compute_header()
automatically, which has the same effect as reading the header from a file.
The header contains the following values, which are stored as attributes
of the Fortune object:
version
numstr
max_length
min_length
flags
delim
numstr is available via the num_fortunes() method; if you're
interested in the others, you'll have to go grubbing through the
Fortune object, e.g.:
$fortune_file = new Fortune ('fortunes');
$fortune_file->read_header ();
$delim = $fortune_file->{'delim'};
read_header() dies if there are any problems reading the header file,
e.g. if it seems to be corrupt or truncated.
read_header() returns the current Fortune object, to allow for
sneaky one-liners (see the examples above).
Reads the contents of the fortune file and computes the header information that would normally be found in a header (.dat) file. This is useful if you maintain a file of fortunes by hand and do not have the corresponding data file.
An optional delimiter argument may be passed to this function; if
present, that delimiter will be used to separate entries in the fortune
file. If not provided, the existing delim attribute of the Fortune
object will be used. If that is not defined, then a percent sign ("%")
will be used.
Returns the number of fortunes found by read_header().
is not yet implemented.
Reads string number NUM from the open fortune file. NUM is zero-based,
ie. it must be between 0 and num_fortunes()-1 (inclusive). croaks if
you haven't opened the file and read the header, or if NUM is out of range.
(Opening the file is pretty hard to screw up, since it's taken care of for
you by the constructor, but you have to read the header explicitly with
read_header().) Returns the text of the fortune as a (possibly)
multiline string.
Picks a random fortune for you and reads it with read_fortune().
Written by Greg Ward <gward@python.net>, 20 February 1999.
Copyright (c) 1999-2000 Gregory P. Ward. All rights reserved. This is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
You can download the Fortune module from my web page:
http://starship.python.net/~gward/perl/
and it can also be found on CPAN.
If you are using an operating system lacking a sufficient sense of
humour to include fortune as part of its standard installation (most
commercial Unices seem to be so afflicted), the Linux world has a
solution: the fortune-mod distribution. The latest version as of
this writing is fortune-mod-9708, and the README file says you can
find it at
http://www.progsoc.uts.edu.au/~dbugger/hacks/hacks.html
This is the fortune implementation on which the Fortune module is
based.