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| Template Toolkit | Modules | Template::Iterator |

## Template::Iterator

| Template::Filters

Template::Namespace::Constants |

Data iterator used by the FOREACH directive

### Table of Contents

- SYNOPSIS
- DESCRIPTION
- PUBLIC METHODS
  - new($data)
  - get_first()
  - get_next()
  - get_all()
  - size()
  - max()
  - index()
  - count()
  - first()
  - last()
  - prev()
  - next()
- AUTHOR
- VERSION
- COPYRIGHT
- SEE ALSO

SYNOPSIS | [ Index ] [ Modules ] [ Top ]

        my $iter = Template::Iterator->new(\@data, \%options);

DESCRIPTION | [ Index ] [ Modules ] [ Top ]

The Template::Iterator module defines a generic data iterator for use by the FOREACH directive. It may be used as the base class for custom iterators.

PUBLIC METHODS | [ Index ] [ Modules ] [ Top ]

### new($data)

Constructor method. A reference to a list of values is passed as the first parameter. Subsequent calls to get_first() and get_next() calls will return each element from the list.

        my $iter = Template::Iterator->new([ 'foo', 'bar', 'baz' ]);

The constructor will also accept a reference to a hash array and will expand it into a list in which each entry is a hash array containing a 'key' and 'value' item, sorted according to the hash keys.

        my $iter = Template::Iterator->new({
    	foo => 'Foo Item',
    	bar => 'Bar Item',
        });

This is equivalent to:

        my $iter = Template::Iterator->new([
    	{ key => 'bar', value => 'Bar Item' },
    	{ key => 'foo', value => 'Foo Item' },
        ]);

When passed a single item which is not an array reference, the constructor will automatically create a list containing that single item.

        my $iter = Template::Iterator->new('foo');

This is equivalent to:

        my $iter = Template::Iterator->new([ 'foo' ]);

Note that a single item which is an object based on a blessed ARRAY references will NOT be treated as an array and will be folded into a list containing that one object reference.

        my $list = bless [ 'foo', 'bar' ], 'MyListClass';
        my $iter = Template::Iterator->new($list);

equivalent to:

        my $iter = Template::Iterator->new([ $list ]);

If the object provides an as_list() method then the Template::Iterator constructor will call that method to return the list of data. For example:

        package MyListObject;

        sub new {
    	my $class = shift;
    	bless [ @_ ], $class;
        }

        package main;

        my $list = MyListObject->new('foo', 'bar');
        my $iter = Template::Iterator->new($list);

This is then functionally equivalent to:

        my $iter = Template::Iterator->new([ $list ]);

The iterator will return only one item, a reference to the MyListObject object, $list.

By adding an as_list() method to the MyListObject class, we can force the Template::Iterator constructor to treat the object as a list and use the data contained within.

        package MyListObject;

        ...

        sub as_list {
    	my $self = shift;
    	return $self;
        }

        package main;

        my $list = MyListObject->new('foo', 'bar');
        my $iter = Template::Iterator->new($list);

The iterator will now return the two item, 'foo' and 'bar', which the MyObjectList encapsulates.

### get_first()

Returns a ($value, $error) pair for the first item in the iterator set. The $error returned may be zero or undefined to indicate a valid datum was successfully returned. Returns an error of STATUS_DONE if the list is empty.

### get_next()

Returns a ($value, $error) pair for the next item in the iterator set. Returns an error of STATUS_DONE if all items in the list have been visited.

### get_all()

Returns a (\@values, $error) pair for all remaining items in the iterator set. Returns an error of STATUS_DONE if all items in the list have been visited.

### size()

Returns the size of the data set or undef if unknown.

### max()

Returns the maximum index number (i.e. the index of the last element) which is equivalent to size() - 1.

### index()

Returns the current index number which is in the range 0 to max().

### count()

Returns the current iteration count in the range 1 to size(). This is equivalent to index() + 1. Note that number() is supported as an alias for count() for backwards compatability.

### first()

Returns a boolean value to indicate if the iterator is currently on the first iteration of the set.

### last()

Returns a boolean value to indicate if the iterator is currently on the last iteration of the set.

### prev()

Returns the previous item in the data set, or undef if the iterator is on the first item.

### next()

Returns the next item in the data set or undef if the iterator is on the last item.

AUTHOR | [ Index ] [ Modules ] [ Top ]

Andy Wardley <abw@andywardley.com> http://www.andywardley.com/

VERSION | [ Index ] [ Modules ] [ Top ]

2.52, distributed as part of the Template Toolkit version 2.08, released on 30 July 2002.

COPYRIGHT | [ Index ] [ Modules ] [ Top ]

      Copyright (C) 1996-2002 Andy Wardley.  All Rights Reserved.
      Copyright (C) 1998-2002 Canon Research Centre Europe Ltd.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO | [ Index ] [ Modules ] [ Top ]

Template

| Template::Filters

Template::Namespace::Constants |

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