Inline::Files(3) User Contributed Perl Documentation Inline::Files(3)NAMEInline::Files - Multiple virtual files at the end of your code
VERSION
This document describes version 0.68 of Inline::Files, released July
23, 2011.
SYNOPSIS
use Inline::Files;
my Code $here;
# etc.
# etc.
# etc.
__FOO__
This is a virtual file at the end
of the data
__BAR__
This is another
virtual
file
__FOO__
This is yet another
such file
WARNING
It is possible that this module may overwrite the source code in files
that use it. To protect yourself against this possibility, you are
strongly advised to use the "-backup" option described in "Safety
first".
This module is still experimental. Regardless of whether you use
"-backup" or not, by using this module you agree that the authors will
b<under no circumstances> be responsible for any loss of data, code,
time, money, or limbs, or for any other disadvantage incurred as a
result of using Inline::Files.
DESCRIPTIONInline::Files generalizes the notion of the "__DATA__" marker and the
associated "<DATA>" filehandle, to an arbitrary number of markers and
associated filehandles.
When you add the line:
use Inline::Files;
to a source file you can then specify an arbitrary number of distinct
virtual files at the end of the code. Each such virtual file is marked
by a line of the form:
__SOME_SYMBOL_NAME_IN_UPPER_CASE__
The following text -- up to the next such marker -- is treated as a
file, whose (pseudo-)name is available as an element of the package
array @SOME_SYMBOL_NAME_IN_UPPER_CASE. The name of the first virtual
file with this marker is also available as the package scalar
$SOME_SYMBOL_NAME_IN_UPPER_CASE.
The filehandle of the same name is magical -- just like "ARGV" -- in
that it automatically opens itself when first read. Furthermore -- just
like "ARGV" -- the filehandle re-opens itself to the next appropriate
virtual file (by "shift"-ing the first element of
@SOME_SYMBOL_NAME_IN_UPPER_CASE into $SOME_SYMBOL_NAME_IN_UPPER_CASE)
whenever it reaches EOF.
So, just as with "ARGV", you can treat all the virtual files associated
with a single symbol either as a single, multi-part file:
use Inline::Files;
while (<FILE>) {
print "$FILE: $_";
}
__FILE__
File 1
here
__FILE__
File 2
here
__OTHER_FILE__
Other file 1
__FILE__
File 3
here
or as a series of individual files:
use Inline::Files;
foreach $filename (@FILE) {
open HANDLE, $filename;
print "<<$filename>>\n";
while (<HANDLE>) {
print;
}
}
__FILE__
File 1
here
__FILE__
File 2
here
__OTHER_FILE__
Other file 1
__FILE__
File 3
here
Note that these two examples completely ignore the lines:
__OTHER_FILE__
Other file 1
which would be accessed via the "OTHER_FILE" filehandle.
Unlike "<ARGV>"/@ARGV/$ARGV, Inline::Files also makes use of the hash
associated with an inline file's symbol. That is, when you create an
inline file with a marker "__WHATEVER__", the hash %WHATEVER will
contain information about that file. That information is:
$WHATEVER{file}
The name of the disk file in which the inlined "__WHATEVER__" files
were defined;
$WHATEVER{line}
The line (starting from 1) at which the current inline
"__WHATEVER__" file being accessed by "<WHATEVER>" started.
$WHATEVER{offset}
The byte offset (starting from 0) at which the current inline
"__WHATEVER__" file being accessed by "<WHATEVER>" started.
$WHATEVER{writable}
Whether the the current inline file being accessed by "<WHATEVER>"
is opened for output.
The hash and its elements are read-only and the entry values are only
meaningful when the corresponding filehandle is open.
Writable virtual files
If the source file that uses Inline::Files is itself writable, then the
virtual files it contains may also be opened for write access. For
example, here is a very simple persistence mechanism:
use Inline::Files;
use Data::Dumper;
open CACHE or die $!; # read access (uses $CACHE to locate file)
eval join "", <CACHE>;
close CACHE or die $!;
print "\$var was '$var'\n";
while (<>) {
chomp;
$var = $_;
print "\$var now '$var'\n";
}
open CACHE, ">$CACHE" or die $!; # write access
print CACHE Data::Dumper->Dump([$var],['var']);
close CACHE or die $!;
__CACHE__
$var = 'Original value';
Unlike "ARGV", if a virtual file is part of a writable file and is
automagically opened, it is opened for full read/write access. So the
above example, could be even simpler:
use Inline::Files;
use Data::Dumper;
eval join "", <CACHE>; # Automagically opened
print "\$var was '$var'\n";
while (<>) {
chomp;
$var = $_;
print "\$var now '$var'\n";
}
seek CACHE, 0, 0;
print CACHE Data::Dumper->Dump([$var],['var']);
__CACHE__
$var = 'Original value';
In either case, the original file is updated only at the end of
execution, on an explicit "close" of the virtual file's handle, or when
"Inline::Files::Virtual::vf_save" is explicitly called.
Creating new Inline files on the fly.
You can also open up new Inline output files at run time. Simply use
the open function with a valid new Inline file handle name and no file
name. Like this:
use Inline::Files;
open IFILE, '>';
print IFILE "This line will be placed into a new Inline file\n";
print IFILE "which is marked by '__IFILE__'\n";
Safety first
Because Inline::Files handles are often read-write, it's possible to
accidentally nuke your hard-won data. But Inline::Files can save you
from yourself.
If Inline::Files is loaded with the "-backup" option:
use Inline::Files -backup;
then the source file that uses it is backed up before the inline files
are extracted. The backup file is the name of the source file with the
suffix ".bak" appended.
You can also specify a different name for the backup file, by
associating that name with the "-backup" flag:
use Inline::Files-backup => '/tmp/sauve_qui_peut';
SEE ALSO
The Inline::Files::Virtual module
The Filter::Util::Call module
BUGS ADDED BY
Alberto Simoes (ambs@cpan.org)
UNWITTING PAWN OF AN AUTHOR
Damian Conway (damian@conway.org)
EVIL MASTERMIND BEHIND IT ALL
Brian Ingerson (INGY@cpan.org)
COPYRIGHT
Copyright (c) 2001-2009. Damian Conway. All rights reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
See http://www.perl.com/perl/misc/Artistic.html
perl v5.14.1 2011-07-23 Inline::Files(3)
