NAME

Tie::Form - access a machine readable database file that minics a hardcopy form

SYNOPSIS

require Tie::Form;

#####
# Using support methods and file handle with
# the file subroutines such as open(), readline()
# print(), close()
#
tie *FORM_FILEHANDLE, 'Tie::Form', @options
$form = tied \*FORM_FILEHANDLE; 

#####
# Using support methods only, no file subroutines
# 
$form = Tie::Form->new(@options);

\$encoded_fields  = $form->decode_record(\$record); 
\@fields          = $form->decode_field(\$encoded_fields);

\$encoded_fields  = $form->encode_field (\@fields);
\$record          = $form->encode_record(\$encoded_fields);

$record           = $form->get_record();

####
# Subroutine interface
#
\$encoded_fields  = decode_record(\$record); 
\@fields          = decode_field(\$encoded_fields);

\$encoded_fields  = encode_field (\@fields);
\$record          = encode_record(\$encoded_fields);

If a subroutine or method will process a list of options, @options, that subroutine will also process an array reference, \@options, [@options], or hash reference, \%options, {@options}.

DESCRIPTION

The Tie::Form module provides a text database file suitable for local data such as private mailing lists. The Tie::Form cannot provide a data warehouse shared by mulitple users.

File format description

Desireable goals for small local private databases file format are as follows:

The database is a text file that can be edited with a simple text editor. How many times have a basebase been corrupted and the data cannot be recoveried? For most people many times. One time is one time too many
The text format resembles as much as possible the standard forms that all civilized people must from time to time fill out in order to survive in a civilized society. Forms are a necessary evil in the pursue of happiness, freedom and prosperity in a civilized society. An example of a form is as follows:
```
manhood length: ________
time spent in big house: _________
what drugs do you use: _________
```
Notice the applicant is not required to specify the form data using Perl hash notation such as
```
manhood_length => 2
```
By the way, that would be your entry. My entry would be
```
manhood_length => 22
```
The political incorrect NH live free or die response would be
```
manhood length: come up to my place and I'll show you
time spent in big house: none of your business
what drugs do you use: put it where the sun doesn't shine
```
The feds response to NH: no federal funding.
The record separator, field separator and any other separator is unique and not embedded in the data. With unique separators, various components of the database may be accessed with simple file read and write functions. There is no need to buffer and process the data to determine if the separator is really a separtor or part of the data.
The format has simple, straightforward method of escaping separators when they are embedded in the data. Escape techiques such as the back-slash besides causing blurred vision also leave the separator embedded in the data. Try looking at the output of the metachar() function and then try to read a eye chart. This is totally unacceptable not only because it impairs vision but also for poor computation performance.

The Tie::Form program module solution is to use separators of the following form:

(not_the_char) . (char) . (not_the_char)

The separators are escaped in embedded text by adding a extra (char) as follows:

sequence             escaped

[^$c]$c[^c]          [^$c]$c$c[^c]
[^$c]$c$c[^c]        [^$c]$c$c$c[^c]

                ...

[^$c]$c x n[^c]      [^$c]$c($c x n)[^c]

SUBROUTINES

This package inherits most of its Tie methods from the Tie::Layers package.

The methods specific to this package are to encode and decode fields and records, and to put and get records as follows:

TIEHANDLE

tie *FORM_FILEHANDLE, 'Tie::Form', @options
tie *FORM_FILEHANDLE, 'Tie::Form', \@options
tie *FORM_FILEHANDLE, 'Tie::Form', \%options
$form = tied \*FORM_FILEHANDLE;

The TIEHANDLE method supports the tie Perl built-in subroutine. The $form object created by tie may be used to access the functions that are in addition to the those established in Tie Handle Perl specification. The available options are as follows:

option      description
---------------------------
EON         End of Name field termination separator
EOD         End of Data field termination separator
EOR         End of Record termination separator
strict      strict processing of EON and EOD

Typically EON, EOD, EOR should be read-only. The requirements for these options are very specific.

encode_field

\$encoded_fields = encode_field (\@fields);

The encode_field subroutine method takes a @fields and returns a encoded_fields string. This subroutine will escape all field separators.

encode_record

\$record = encode_record(\$encoded_fields);

The encode_record subroutine takes a $encoded_fields string and encodes it as $record. This subroutines escapes the record separator and embeds the record separator in the $record string.

decode_field

\@fields = decode_field(\$encoded_fields);

The decode_fiel subroutine takes $encoded_fields, unescape the field separators, decodes the fields and places the results in @fields. The @fields array is ordered name, value pairs of the fields. The even array elements are the field names and the following odd array element is the field data.

The below code will convert the decoded @fields to a hash:

%fields = @fields

decode_record

\$encoded_fields  = decode_record(\$record);

The decode_record subroutine takes a $record string, removes the record separator, unescapes the record separator in the fields string and leaves the fields string in $encoded_fields.

get_record

$record = $form->get_record();

The get_record method reads a fully encoded $record from the underlying file of the object.

new

$form = Tie::Form->new(@options);
$form = Tie::Form->new(\@options);
$form = Tie::Form->new(\%options);

The new method provides an object that may be used to access the functions that are in addition to the those established in Tie Handle Perl specification. The @options are the same as TIEHANDLE.

REQUIREMENTS

The general STD::TestGen Perl module requirements are as follows:

general [1] - load: shall[1] load without error and
general [2] - pod check: shall[2] passed the Pod::Checker check without error.

File format requirements

For most databases, the file format is hidden. In this case, since the file may be accessed and edited by any text editor, the file format requirements must be rigorously established in order that they may be properly edited.

The Tie::Form module file format will be as follows:

$field_name: $field_data ^

     ...

$field_name: $field_data ^
~-~

    ...

~-~
$field_name: $field_data ^

     ...

$field_name: $field_data ^
~-~

The requirements for the file format are as follows:

format [1] - separator strings

The format separator strings shall[1] be as follows:

End of Field Name (EON):  [^:]:[^:]
ENd of Field Data (EOD):  [^\^]\^[^\^]
End of Record(EOR):  ~-~

The separator strings have the following format:

(not_the_char) . (char) . (not_the_char)

The '^' character was and still available in console text editors as a cursor. Because it appears very rarely in text, it is a good choice for use in a separator string. If it does not appear a lot, it will not have to be escaped a lot. The "~-~" separator sequence is a natural looking text section separator.

format [2] - separator escapes

Separator strings embedded in $field_name and $field_data strings shall[2] be escaped by adding one additional middle character. Escaped sequences must also be escaped. An escaped separator sequence will always have one additional middle character from an unescaped separator sequence.

format [3] - field names

The characters [\x00-\x1f] shall[3] not be allowed in $field_name strings. Spaces will be allowed. The character set [\x00-\x1f] are the ASCII control characters. See ascii.computerdiamonds.com. Embedded [\x00-\x1f] characters will be converted to the '_' character.

format [4] - field names

Leading and trailing [ \x00-\x1f] characters in any potential $field_name string shall[4] not be part of the $field_name and discarded.

format [5] - EON

A leading [^:] in the EON separator that is not a [ \x00-\x1f] shall[5] be the be the last character in the $field_name string; otherwise, it is not part of the the $field_name string and discarded. For the situation where the last part of a $field_name string is an escape sequence a [ \x00-\x1f] will be required between the $field_name string and the EON. The following is a valid $field_name EON sequence:

escaped              unescaped

field_name:: :       fieldname:

format [6] - Strict EOD

For the strict format option, the leading [^\^] of the EOD shall[6] not be part of the $field_data. The [^\^] character may be any character including the [\x00-\x1f] characters.

Examples of strict format option are as follows:

$field_name: $data ^
$field_name: $data$c^

$field_name: 
line1
  ..
line2
^

The $field_data for the above example is as follows:

Example               $field_data   

"$data ^"             "$data"  
"$data$c^"            "$data"
"$line1\n$line2\n^"   "$line1\n$line2"

format [7] - Lenient EOD

For the lenient format option, the leading [^\^] of the EOD shall[7] be part of the $field_data. The lenient format has ambiguous case when the last character in the $field_data is the [\^] character. In order to be valid, a [^\^] must be used before the [\^], making the [^\^] part of the $field_data whether that is intended or not. For example in, "$data^^ ^", the $field_data is "$data^ " whether or not the space is intended as part of the $field_data. If this cannot be tolerated for an application the strict format opion should be specified.

Examples of lenient format option are as follows:

$field_name: $data1 ^

$field_name: $data2^

$field_name: 
$line1
$line2
^

The $field_data for the above example is as follows:

Example               $field_data   

"$data1 ^"            "$data1 "  
"$data2^"             "$data2"
"$line1\n$line2\n^"   "$line1\n$line2\n"

Methods requirements

There are two options, that impact the methodsas follows:

strict => 1 option: This option determines whether to encode a field in strict or lenient format.
binary => 1 option: This option determines whether or not to process carriage returns and line feeds. Different operating systems handle these characters differently for text files.

The requirements for the methods are as follows:

methods [1] - encode_field

$field = $tdb->encode_field (\@fields, \$fields)

The @fields array will contain a number of fields. The $field_names will be the even elements and the $field_data the following odd elements.

The encode_field subroutine shall[1] encode the $field_name string and $field_data string into the $field string in accordance with the File Format requirements. The encoding shall escape the EON and EOD separators and embed the EON and EOD separators.

The encoding will be conservative in complying with the File Format requirements.

As established by the File Format requirements, the encoding will be different depending upon the value of the strict option, $tdb->{options}->{strict}.

methods [2] - decode_field

$success = $tdb->decode_field(\$fields, \@fields)

The decode_field subroutine shall[2] decode a $record string into the @fields array in accordance with the File Format requirements. The $field_names will be the even elements in the @fields array and the $field_data the following odd elements.

The decoding will be liberal what it considers that complies to the File Format requirements.

As established by the File Format requirements, the decoding will be different depending upon the value of the strict option, $tdb->{options}->{strict}.

methods [3] - encode_record

$success = $tdb->encode_record(\$fields, \$record) 
$success = $tdb->encode_record( \$fields)

The encode_record subroutine shall[3] encode the $fields string into the $record string in accordance with File Format requirements. If the $record string is absence or the \$record reference and the \$fields reference are the same, the encoding will modify the \$fields string. In this case, the encoding will not perserve the $fields string. The encoding will escape the EOR and embed the EOR.

methods [4] - decode_record

$success  = $tdb->decode_record(\$record, \$fields) 
$success  = $tdb->decode_record(\$record)

The decode_record subroutine shall[4] decode the $record string and into the $fields string in accordance with the File Format requirements. If the $fields string is absence or the \$record reference and the \$fields reference are the same, the encoding will modify the \$record string. In this case, the encoding will not perserve the $record string. The decoding will remove the EOR and unescape the EOR.

methods [5] - put_record

$success = $tdb_out->put_record( \$record )

The put_record subroutine shall[5] write out the $record to the file specified when the object $tdb_out was created with the following statement

$tdb_out = Tie::Form( flag => '>', file => $file, @options );

methods [6] - get_record

$success = $tdb_in->get_record( \$record )

The get_record subroutine shall[6] read a $record from the file specified when the object $tdb_in was created with the following statement

$tdb_in = Tie::Form( flag => '<', file=>$file, @options );

methods [7] - get_record

Unless $tdb_in was created with the binary option, {binary => 1}, the get_record subroutine shall[7] translate any "\015\012" combination into the "\n" for the current operating system.

Tie::Layers

The methods inherit from Tie::Layers will comply to the Tie::Layers requirements

DEMONSTRATION

#########
# perl Form.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;
    use File::SmartNL;
    use File::Spec;

    my $uut = 'Tie::Form'; # Unit Under Test
    my $fp = 'File::Package';
    my $loaded;

    my (@fields);  # force context
    my $out_file = File::Spec->catfile('_Form_','form1.txt');;
    unlink $out_file;

    my $lenient_in_file = File::Spec->catfile('_Form_','lenient0.txt');
    my $strict_in_file = File::Spec->catfile('_Form_','strict0.txt');

    my $version = $Tie::Form::VERSION;
    $version = '' unless $version;

##################
# Load UUT
# 

my $errors = $fp->load_package($uut)
$errors

# ''
#

##################
# Tie::Form Version  loaded
# 

$fp->is_package_loaded($uut)

# 1
#

##################
# Read lenient Form
# 

    tie *FORM, 'Tie::Form';
    open FORM,'<',File::Spec->catfile($lenient_in_file);
    @fields = <FORM>;
    close FORM;
[@fields]

# [
#          [
#            'UUT',
#            'File/Version.pm',
#            'File_Spec',
#            '',
#            'Revision',
#            '',
#            'End_User',
#            '',
#            'Author',
#            'http://www.SoftwareDiamonds.com support@SoftwareDiamonds.com',
#            'SVD',
#            'SVD::DataCop-DataFile',
#            'Template',
#            'STD/STD001.frm'
#          ],
#          [
#            'Email',
#            'nobody@hotmail.com',
#            'Form',
#            'Udo-fully processed oils',
#            'Tutorial',
#            '*~~* Better Health thru Biochemistry *~~*',
#            'REMOTE_ADDR',
#            '213.158.186.150',
#            'HTTP_USER_AGENT',
#            'Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt)',
#            'HTTP_REFERER',
#            'http://computerdiamonds.com/'
#          ],
#          [
#            'EOF',
#            '\n',
#            'EOL',
#            '\n^\n',
#            'EOV',
#            '}',
#            'SOV',
#            '${'
#          ],
#          [
#            'EOF',
#            '^',
#            'EOL',
#            '~-~',
#            'SOV',
#            '${',
#            'EOV',
#            '}'
#          ],
#          [
#            'EOF',
#            '^^',
#            'EOL',
#            '~---~',
#            'SOV',
#            '${',
#            'EOV',
#            '}'
#          ]
#        ]
#

##################
# Write lenient Form
# 

    open FORM, '>', $out_file;
    print FORM @fields;
    close FORM;
File::SmartNL->fin($out_file)

# 'UUT: File/Version.pm^
#File_Spec: ^
#Revision: ^
#End_User: ^
#Author: http://www.SoftwareDiamonds.com support@SoftwareDiamonds.com^
#SVD: SVD::DataCop-DataFile^
#Template: STD/STD001.frm^
#~-~
#Email: nobody@hotmail.com^
#Form: Udo-fully processed oils^
#Tutorial: *~~* Better Health thru Biochemistry *~~*^
#REMOTE_ADDR: 213.158.186.150^
#HTTP_USER_AGENT: Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt)^
#HTTP_REFERER: http://computerdiamonds.com/^
#~-~
#EOF: \n^
#EOL: \n^^\n^
#EOV: }^
#SOV: ${^
#~-~
#EOF: ^^ ^
#EOL: ~--~^
#SOV: ${^
#EOV: }^
#~-~
#EOF: ^^^ ^
#EOL: ~----~^
#SOV: ${^
#EOV: }^
#~-~
#'
#

##################
# Read strict Form
# 

    tie *FORM, 'Tie::Form';
    open FORM,'<',File::Spec->catfile($strict_in_file);
    @fields = <FORM>;
    close FORM;
[@fields]

# [
#          [
#            'UUT',
#            'File/Version.pm',
#            'File_Spec',
#            '',
#            'Revision',
#            '',
#            'End_User',
#            '',
#            'Author',
#            'http://www.SoftwareDiamonds.com support@SoftwareDiamonds.com',
#            'SVD',
#            'SVD::DataCop-DataFile',
#            'Template',
#            'STD/STD001.frm'
#          ],
#          [
#            'Email',
#            'nobody@hotmail.com',
#            'Form',
#            'Udo-fully processed oils',
#            'Tutorial',
#            '*~~* Better Health thru Biochemistry *~~*',
#            'REMOTE_ADDR',
#            '213.158.186.150',
#            'HTTP_USER_AGENT',
#            'Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt)',
#            'HTTP_REFERER',
#            'http://computerdiamonds.com/'
#          ],
#          [
#            'EOF',
#            '\n',
#            'EOL',
#            '\n^\n',
#            'EOV',
#            '}',
#            'SOV',
#            '${'
#          ],
#          [
#            'EOF',
#            '^',
#            'EOL',
#            '~-~',
#            'SOV',
#            '${',
#            'EOV',
#            '}'
#          ],
#          [
#            'EOF',
#            '^^',
#            'EOL',
#            '~---~',
#            'SOV',
#            '${',
#            'EOV',
#            '}'
#          ]
#        ]
#

##################
# Write strict Form
# 

    open FORM, '>', $out_file;
    print FORM @fields;
    close FORM;
File::SmartNL->fin($out_file)

# 'UUT: File/Version.pm^
#File_Spec: ^
#Revision: ^
#End_User: ^
#Author: http://www.SoftwareDiamonds.com support@SoftwareDiamonds.com^
#SVD: SVD::DataCop-DataFile^
#Template: STD/STD001.frm^
#~-~
#Email: nobody@hotmail.com^
#Form: Udo-fully processed oils^
#Tutorial: *~~* Better Health thru Biochemistry *~~*^
#REMOTE_ADDR: 213.158.186.150^
#HTTP_USER_AGENT: Mozilla/4.0 (compatible; MSIE 5.0; Windows 98; DigExt)^
#HTTP_REFERER: http://computerdiamonds.com/^
#~-~
#EOF: \n^
#EOL: \n^^\n^
#EOV: }^
#SOV: ${^
#~-~
#EOF: ^^ ^
#EOL: ~--~^
#SOV: ${^
#EOV: }^
#~-~
#EOF: ^^^ ^
#EOL: ~----~^
#SOV: ${^
#EOV: }^
#~-~
#'
#
unlink $out_file;

QUALITY ASSURANCE

The module t::Tie::Form is the Software Test Description(STD) module for the "Tie::Form". module.

To generate all the test output files, run the generated test script, run the demonstration script, execute the following in any directory:

tmake -verbose -demo -run -test_verbose -pm=t::Tie::Form

Note that tmake.pl must be in the execution path $ENV{PATH} and the "t" directory on the same level as the "lib" that contains the Tie::Form program module.

NOTES

Binding Requirements

In accordance with the License, Software Diamonds is not liable for any requirement, binding or otherwise.

Author

The author, holder of the copyright and maintainer is

<support@SoftwareDiamonds.com>

Copyright

License

Software Diamonds permits the redistribution and use in source and binary forms, with or without modification, provided that the following conditions are met:

Redistributions of source code, modified or unmodified must retain the above copyright notice, this list of conditions and the following disclaimer.
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 distribution.
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 SOFTWARE '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 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING USE OF THIS SOFTWARE, EVEN IF ADVISED OF NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE POSSIBILITY OF SUCH DAMAGE.

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