ntext(3) Alternative Bindings for the Text Widget

SYNOPSIS

package require Tcl 8.5

package require Tk 8.5

package require ntext ?0.81?




DESCRIPTION

The purpose of the ntext package is to make the text widget behave more like other text-editing applications. It makes the text widget more useful for implementing a text editor, and makes it behave in a way that will be more familiar to most users.

The package provides a binding tag named Ntext for use by text widgets in place of the default Text binding tag.

Package ntext 's functions and variables are contained entirely in the ::ntext namespace; its other code is contained in the binding tag Ntext. ntext has no exports to the global or other namespaces, and no new widget commands. It uses modified copies of the Tk code, leaving the original code, and the Text binding tag, unchanged.

The differences between the Ntext binding tag and the default Text binding tag are in three categories:

  • Some Text bindings behave differently from most text-editing applications. Ntext gives these bindings more familiar behaviour. For details see ntextBindings.
  • When a logical line with leading whitespace is word-wrapped onto more than one display line, the wrapped display lines begin further to the left than the first display line, which can make the text layout untidy and difficult to read. Ntext can indent the wrapped lines to match the leading whitespace of the first display line (this facility is switched off by default). For details see ntextIndent.
  • When the user navigates or selects text, Tcl/Tk sometimes needs to detect word boundaries. Ntext provides improved rules for word boundary detection. For details see ntextWordBreak.

The remainder of this page describes the basic use and configuration of all three aspects of Ntext. For more detailed information on the different facilities of Ntext, see the pages ntextBindings, ntextIndent, and ntextWordBreak.

See Section EXAMPLE for how to apply the Ntext binding tag in place of the Text binding tag.

CONFIGURATION OPTIONS

Ntext provides alternatives to a number of behaviours of the classic Text binding tag. Where there is an option, the Ntext behaviour (except for display-line indentation) is switched on by default.

The behaviour of Ntext may be configured application-wide by setting the values of a number of namespace variables:

::ntext::classicAnchor

  • 0 - (default value) selects Ntext behaviour, i.e. the anchor point is fixed
  • 1 - selects classic Text behaviour, i.e. the anchor point is variable

::ntext::classicExtras

  • 0 - (default value) selects Ntext behaviour, i.e. several traditional Text bindings are de-activated
  • 1 - selects classic Text behaviour, i.e. all Text bindings are activated

::ntext::classicMouseSelect

  • 0 - (default value) selects Ntext behaviour, i.e. the anchor point for mouse selection operations is moved by keyboard navigation
  • 1 - selects classic Text behaviour

::ntext::classicWordBreak

  • 0 - (default value) selects Ntext behaviour, i.e. platform-independent, two classes of word characters and one class of non-word characters.
  • 1 - selects classic Text behaviour, i.e. platform-dependent, one class of word characters and one class of non-word characters
  • After changing this value, the matching patterns should be recalculated. See ntextWordBreak for details and advanced configuration options.

::ntext::classicWrap

  • 0 - selects Ntext behaviour, i.e. display lines of text widgets in -wrap word mode are indented to match the initial whitespace of the first display line of a logical line. If the widget already holds text when this value is set, a function call may be necessary. See ntextIndent for detailed instructions on the use of Ntext 's indentation.
  • 1 - (default value) selects classic Text behaviour, i.e. no indentation

::ntext::overwrite

  • 0 - (initial value) text typed at the keyboard is inserted into the widget
  • 1 - text typed at the keyboard overwrites text already in the widget
  • The value is toggled by the Insert key.

EXAMPLE

To create a text widget .t and use the Ntext bindings: 
package require ntext
text .t
bindtags .t {.t Ntext . all}
See bindtags for more information.

KEYWORDS

bindtags, re_syntax, regexp, text

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