File::SmartNL(3) User Contributed Perl Documentation File::SmartNL(3)NAMEFile::SmartNL - slurp text files no matter the New Line (NL) sequence
SYNOPSIS
#####
# Subroutine Interface
#
use File::SmartNL qw(config fin fout smartnl);
$old_value = config( $option );
$old_value = config( $option => $new_value);
(@all_options) = config( );
$data = smart_nl($data);
$data = fin( $file_name, @options );
$char_count = fout($file_name, $data, @options);
######
# Object Interface
#
use File::SmartNL;
$default_options = File::SmartNL->default(@options);
$old_value = $default_options->config( $option );
$old_value = $default_options->config( $option => $new_value);
(@all_options) = $default_options->config( );
$data = File::SmartNL->smart_nl($data);
$data = File::SmartNL->fin( $file_name, @options );
$char_count = File::SmartNL->fout($file_name, $data, @options);
Generally, if a subroutine will process a list of options, @options,
that subroutine will also process an array reference, "\@options",
"[@options]", or hash reference, "\%options", "{@options}". If a sub-
routine will process an array reference, "\@options", "[@options]",
that subroutine will also process a hash reference, "\%options",
"{@options}". See the description for a subroutine for details and
exceptions.
DESCRIPTION
Different operating systems have different sequences for new-lines.
Historically when computers where first being born, one of the main-
stays was the teletype. The teletype understood ASCII. The teletype
was an automated typewriter that would perform a carriage return when
it received an ASCII Carriage Return (CR), \015, character and a new
line when it received a Line Feed (LF), \012 character.
After some time came Unix. Unix had a tty driver that had a raw mode
that sent data unprocessed to a teletype and a cooked mode that per-
formed all kinds of translations and manipulations. Unix stored data
internally using a single NL character at the ends of lines. The tty
driver in the cooked mode would translate the New Line (NL) character
to a CR,LF sequence. When driving a teletype, the physicall action of
performing a carriage return took some time. By always putting the CR
before the LF, the teletype would actually still be performing a car-
riage return when it received the LF and started a line feed.
After some time came DOS. Since the tty driver is actually one of the
largest peices of code for UNIX and DOS needed to run in very cramp
space, the DOS designers decided, that instead of writing a tailored
down tty driver, they would stored a CR,LF in the internal memory. Data
internally would be either 'text' data or 'binary' data.
Needless to say, after many years and many operating systems about
every conceivable method of storing new lines may be found amoung the
various operating systems. This greatly complicates moving files from
one operating system to another operating system.
The smart NL methods in this package are designed to take any combina-
tion of CR and NL and translate it into the special NL seqeunce used on
the site operating system. Thus, by using these methods, the messy
problem of moving files between operating systems is mostly hidden in
these methods. By using the "fin" and "fout" methods, text files may
be freely exchanged between operating systems without any other pro-
cessing.
The one thing not hidden is that the methods need to know if the data
is 'text' data or 'binary' data. Normally, the assume the data is
'text' and are overriden by setting the 'binary' option.
Perl 5.6 introduced a built-in smart nl functionality as an IO disci-
pline :crlf. See Programming Perl by Larry Wall, Tom Christiansen and
Jon Orwant, page 754, Chapter 29: Functions, open function. For Perl
5.6 or above, the :crlf IO discipline my be preferable over the
smart_nl method of this program module.
SUBROUTINES
config
$old_value = config( $option );
$old_value = config( $option => $new_value);
(@all_options) = config( );
When Perl loads the "File::SmartNL" program module, Perl creates a
$File::Drawing::default_options object using the "default" method.
Using the "config" as a subroutine
config(@_)
writes and reads the $File::Drawing::default_options object directly
using the Data::Startup::config method. Avoided the "config" and in
multi-threaded environments where separate threads are using
"File::Drawing". All other subroutines are multi-thread safe. They
use "override" to obtain a copy of the $File::Drawing::default_options
and apply any option changes to the copy keeping the original intact.
Using the "config" as a method,
$options->config(@_)
writes and reads the $options object using the Data::Startup::config
method. It goes without saying that that object should have been cre-
ated using one of the following or equivalent:
$default_options = $class->File::Drawing::defaults(@_);
The underlying object data for the "File::SmartNL" class of objects is
a hash. For object oriented conservative purist, the "config" subrou-
tine is the accessor function for the underlying object hash.
Since the data are all options whose names and usage is frozen as part
of the "File::Drawing" interface, the more liberal minded, may avoid
the "config" accessor function layer, and access the object data
directly.
defaults
The "defaults" subroutine establish "File::Drawing" class wide options
options as follows:
option initial value
--------------------------------------------
warn 1
binary 0
fin
$data = fin( $file_name )
$data = fin( $file_name, @options )
$data = fin( $file_name, [@options] )
$data = fin( $file_name, {@options} )
For the "binary" option, the "fin" subroutine reads $data from the
$file_name as it; otherwise, it converts any CR LF sequence to the the
logical Perl "\n" character for site.
fout
$success = fout($file_name, $data)
$success = fout($file_name, $data, @options)
$success = fout($file_name, $data, [@options])
$success = fout($file_name, $data, {@options})
For the "binary" option, the "fout" subroutine writes out the $data to
the $file_name as it; otherwise, it converts the logical Perl "\n"
character to th site CR LF sequence for a NL.
smart_nl
$data = smart_nl( $data )
The "smart_nl" subroutine converts any combination of CR and LF to the
NL of the site operationg system.
REQUIREMENTS
Someday.
DEMONSTRATION
#########
# perl SmartNL.d
###
~~~~~~ Demonstration overview ~~~~~
The results from executing the Perl Code follow on the next lines as
comments. For example,
2 + 2
# 4
~~~~~~ The demonstration follows ~~~~~
use File::Package;
my $fp = 'File::Package';
my $uut = 'File::SmartNL';
my $loaded = '';
my $expected = '';
my $data = '';
VO:
##################
# UUT not loaded
#
$loaded = $fp->is_package_loaded('File::Where')
# ''
#
##################
# Load UUT
#
my $errors = $fp->load_package($uut, 'config')
$errors
# ''
#
unlink 'test.pm';
$expected = "=head1 Title Page\n\nSoftware Version Description\n\nfor\n\n";
$uut->fout( 'test.pm', $expected, {binary => 1} );
##################
# fout Unix fin
#
$uut->fin( 'test.pm' )
# '=head1 Title Page
#Software Version Description
#for
#'
#
unlink 'test.pm';
$data = "=head1 Title Page\r\n\r\nSoftware Version Description\r\n\r\nfor\r\n\r\n";
$uut->fout( 'test.pm', $data, {binary => 1} );
##################
# fout Dos Fin
#
$uut->fin('test.pm')
# '=head1 Title Page
#Software Version Description
#for
#'
#
unlink 'test.pm';
$data = "line1\015\012line2\012\015line3\012line4\015";
$expected = "line1\nline2\nline3\nline4\n";
##################
# smart_nl
#
$uut->smart_nl($data)
# 'line1
#line2
#line3
#line4
#'
#
##################
# read configuration
#
[config('binary')]
# [
# 'binary',
# 0
# ]
#
##################
# write configuration
#
[config('binary',1)]
# [
# 'binary',
# 0
# ]
#
##################
# verify write configuration
#
[config('binary')]
# [
# 'binary',
# 1
# ]
#
QUALITY ASSURANCE
Running the test script "SmartNL.t" verifies the requirements for this
module. The "tmake.pl" cover script for Test::STDmaker automatically
generated the "SmartNL.t" test script, "SmartNL.d" demo script, and
"t::File::SmartNL" STD program module POD, from the "t::File::SmartNL"
program module contents. The "tmake.pl" cover script automatically ran
the "SmartNL.d" demo script and inserted the results into the 'DEMON-
STRATION' section above. The "t::File::SmartNL" program module is in
the distribution file File-SmartNL-$VERSION.tar.gz.
NOTES
Author
The holder of the copyright and maintainer is
<support@SoftwareDiamonds.com>
Copyright
Copyrighted (c) 2002 Software Diamonds
All Rights Reserved
Binding Requirements Notice
Binding requirements are indexed with the pharse 'shall[dd]' where dd
is an unique number for each header section. This conforms to standard
federal government practices, STD490A 3.2.3.6. In accordance with the
License, Software Diamonds is not liable for any requirement, binding
or otherwise.
License
Software Diamonds permits the redistribution and use in source and
binary forms, with or without modification, provided that the following
conditions are met:
1 Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2 Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribu-
tion.
3 Commercial installation of the binary or source must visually
present to the installer the above copyright notice, this list of
conditions intact, that the original source is available at
http://softwarediamonds.com and provide means for the installer to
actively accept the list of conditions; otherwise, a license fee
must be paid to Softwareware Diamonds.
SOFTWARE DIAMONDS, http://www.softwarediamonds.com, PROVIDES THIS SOFT-
WARE 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SOFTWARE DIAMONDS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,EXEMPLARY, OR
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SEE ALSO
Docs::Site_SVD::File_SmartNL
Test::STDmaker
ExtUtils::SVDmaker
perl v5.8.8 2004-05-13 File::SmartNL(3)