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 Tk::Reindex - change the base index of Text-like widgets


Tk::Reindex - change the base index of Text-like widgets


    use Tk::ReindexedText;
    $t1=$w->ReindexedText(-linestart => 2);
    use Tk::ReindexedROText;
    $t2=$w->ReindexedROText(-linestart => 0);


Creates a new widget class based on Text-like widgets that can redefine the line number base (normally Text widgets start line numbers at 1), or possibly other manipulations on indexes.


The newly-defined widget takes all the same options as the base widget, which defaults to Text.


Name: lineStart
Class: LineStart
Switch: -linestart
Sets the line number of the first line in the Text widget. The default -toindexcmd and -fromindexcmd use this configuration option.

-item Name: toIndexCmd fromIndexCmd

-item Class: ToIndexCmd FromIndexCmd

-item Switch: -toindexcmd -fromindexcmd

These two options specify callbacks that are called with a list of indexes and are responsible for translating them to/from indexes that the base Text widget can understand. The callback is passed the widget followed by a list of indexes, and should return a list of translated indexes. -toindexcmd should translate from 'user' indexes to 'native' Text-compatible indexes, and -fromindexcmd should translate from 'native' indexes to 'user' indexes.

The default callbacks simply add/subtract the offset given by the -linestart option for all indexes in 'line.character' format.

It would probably be prudent to make these functions inverses of each other.


To make new Reindex widgets, this function should be called via use with the name of the Text-like base class that you are extending with ``Reindex'' capability. 'use base(Tk::Reindex Tk::nameofbasewidget)' should also be specified for that widget.


I've used the word ``indexes'' instead of ``indices'' throughout the documentation.

All the built-in perl code for widget bindings & methods will use the new 'user' indexes. Which means all this index manipulation might might break code that is trying to parse/manipulate indexes. Or even assume that '1.0' is the beginning index. Tk::Text::Contents comes to mind.


Andrew Allen <ada@fc.hp.com>

This code may be distributed under the same conditions as Perl.

 Tk::Reindex - change the base index of Text-like widgets