NAME

BoutrosLab::TSVStream::Format::None::Dyn

SYNOPSIS

use BoutrosLab::TSVStream::Format::None::Dyn;

# you know ./myfile1 has a valid header line
my $reader1 = BoutrosLab::TSVStream::Format::None::Dyn->reader(
	file => "./myfile1" );

my $flds;
while (my $rec1 = $reader1->read) {
	$flds //= $rec->dyn_fields; # first time, get the field names
	$vals   = $rec->dyn_values;   # get the field values
	# use the record: $flds: [f1,f2,f3,...], $vals: [v1,v2,v3,...]
	}

# ./myfile2 has no header line
my $reader2 = BoutrosLab::TSVStream::Format::None::Dyn->reader(
	file       => "./myfile2",
	dyn_fields => [ qw(foo bar baz) ],
);
while (my $rec = $reader2->read) {
	$vals = $rec->dyn_values;   # get the field values
	# use the record: flds: [foo,bar,baz], $vals: [v1,v2,v3]
	}

my $writer1 = BoutrosLab::TSVStream::Format::None::Dyn->writer(
	file       => "myoutfile",
	dyn_fields => [ qw(name address ],
	);

$writer1->write( 'Larry Wall', 'Republic of Perl' );
# myfile will contain 2 lines:
# name<TAB>address
# Larry Wall<TAB>Republic of Perl

my $writer2 = BoutrosLab::TSVStream::Format::None::Dyn->writer(
	file   => "myoutfile",
	header => 'skip',
	);

$writer2->write( 'Larry Wall', 'Republic of Perl' );
# myfile will contain 1 line:
# Larry Wall<TAB>Republic of Perl

DESCRIPTION

This class provides methods to read or write streams of tab separated fields, with no compile-time plan for the nummber of fields or their names.

A reader will determine the name of the fields (and thus their number) either from an explicit list, or from the first line of the input stream (in which case, that stream must have been written with a header line providing the names).

The returned reader will have a read method - each time it is invoked, it returns a record for the next item in the stream (or undef at end of the stream). The returned record will have two attributes - dyn_fields is a ArrayRef[Str] with the names of the fields (possibly 'extra1', 'extra2', ... if no names or header were provided), and - dyn_values is a ArrayRef[Str] containing the valules of the fields for this record.

A writer should be provided the names of the fields, otherwise it will set the names to be 'extra1', 'extra2', ... and write those names (unless you have specified that header writting is to be skipped).

It will provide a write method that can take an array of strings, or a ist of strings or an Object that is a subclass of BoutrosLab::TSVStream::Format. After the number of fields has been determined (either from a provided dyn_fields in the writer call, or by reading a header line, or by couting the number of fields in the first write; all subsequent write calls must provide the same number of fields.

SEE ALSO

BoutrosLab::TSVStream::IO

for a description of reader and writer objects. This module only allows for the dynamic fields, internally providing an empty list for the fixed fields.

BoutrosLab::TSVStream::Format::*

for objects that include a known set of fields, and can provide explicit type validation for those fields. If you are using the same set of fields in many places, it would be well-advised to define a sub-class that describes your set in better detail. As well as providing the ability to type-check the fields, that also gets you the ability to retrieve the field values by name.

AUTHOR

John Macdonald - Boutros Lab

ACKNOWLEDGEMENTS

Paul Boutros, Phd, PI - Boutros Lab

The Ontario Institute for Cancer Research