---+ Package =TWiki::ListIterator= Iterator over a list %TOC% ---++ new(\@list) Create a new iterator over the given list. Designed primarily for operations over fully defined lists of object references. The list is not damaged in any way. ---++ hasNext() -> $boolean Returns false when the iterator is exhausted. <verbatim> my $it = new TWiki::ListIterator(\@list); while ($it->hasNext()) { ... </verbatim> ---++ next() -> $data Return the next entry in the list. The iterator object can be customised to pre- and post-process entries from the list before returning them. This is done by setting two fields in the iterator object: * ={filter}= can be defined to be a sub that filters each entry. The entry will be ignored (next() will not return it) if the filter returns false. * ={process}= can be defined to be a sub to process each entry before it is returned by next. The value returned from next is the value returned by the process function. For example, <verbatim> my @list = ( 1, 2, 3 ); my $it = new TWiki::ListIterator(\@list); $it->{filter} = sub { return $_[0] != 2 }; $it->{process} = sub { return $_[0] + 1 }; while ($it->hasNext()) { my $x = $it->next(); print "$x, "; } </verbatim> will print <verbatim> 2, 4 </verbatim>
This topic: TWiki
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TWikiListIteratorDotPm
Topic revision: r1 - 2008-01-22 - TWikiContributor
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