Reindex

Section: perl/Tk Documentation (3)
Updated: 2021-01-27
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NAME

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

SYNOPSIS

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

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

DESCRIPTION

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.

STANDARD OPTIONS

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

WIDGET-SPECIFIC OPTIONS

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.

CLASS METHODS

import: 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.

BUGS

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.

AUTHOR

Andrew Allen <ada@fc.hp.com>

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