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# term::interact::pager(n) 0.1 tcllib "Terminal control"

## Name

term::interact::pager - Terminal widget, paging

## Synopsis

- package require Tcl 8.4
- package require term::interact::pager ?0.1?

- term::interact::pager object text ?options...?
- object interact
- object done
- object clear
- object text text
- object configure
- object configure option
- object configure option value...
- object cget option

## Description

This package provides a class for the creation of a simple paging text display.

## Class API

The package exports a single command, the class command, enabling the creation of pager instances. Its API is:

term::interact::pager object text ?options...?

  This command creates a new pager object with the name object, initializes it, and returns the fully qualified name of the object command as its result.

  The argument is the text to show, possibly followed by configuration options and their values. The options are explained in the section Configuration.

## Object API

The objects created by the class command provide the methods listed below:

object interact

  Show the pager in the screen at the configured location and start interacting with it. This opens its own event loop for the processing of incoming characters. The method returns when the interaction has completed. See section Interaction for a description of the possible interaction.

object done

  This method can be used by user supplied actions to terminate the interaction with the object.

object clear

  This method can be used by user supplied actions to remove the pager from the terminal.

object text text

  This method can be used to change the text shown by the pager. The pager will reset the dispay to show the first line of the text at the top.

object configure
object configure option
object configure option value...
object cget option

  Standard methods to retrieve and configure the options of the pager.

## Configuration

A pager instance recognizes the following options:

-in chan

  Specifies the channel to read character sequences from. Defaults to stdin.

-out chan

  Specifies the channel to write the pager contents to. Defaults to stdout.

-column int

  Specifies the column of the terminal where the left margin of the pager display should appear. Defaults to 0, i.e. the left-most column.

-line int

  Specifies the line of the terminal where the top margin of the pager display should appear. Defaults to 0, i.e. the top-most line.

-height int

  Specifies the number of lines of text to show at most in the display. Defaults to 25.

-actions dict

  Specifies a dictionary containing additional actions, using character sequences as keys. Note that these sequences cannot override the hardwired sequences described in section Interaction.

## Interaction

A pager object recognizes the control sequences listed below and acts as described. The user can supply more control sequences to act on via the configuration, but is not able to overide these defaults.

Cursor Up

  The text is scrolled down a single line, making one more line visible at the top. The pager will not react if the first line of the text is already shown.

Cursor Down

  The text is scrolled up a single line, making one more line visible at the bottom. The pager will not react if the last line of the text is already shown.

Page Up

  The text is scrolled down a page. The pager will not react if the first line of the text is already shown.

Page Down

  The text is scrolled up a page. The pager will not react if the last line of the text is already shown.

Enter/Return

  The interaction with the object is terminated.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category term of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

## Keywords

control, pager, terminal, text display

## Category

Terminal control

## Copyright

Copyright © 2006 Andreas Kupries <andreas_kupries@users.sourceforge.net>