11 Dynamic Loading

▼ |  | The Racket Graphical Interface Toolkit

1 | Windowing
2 | Widget Gallery
3 | Windowing Classes
4 | Windowing Functions
5 | Editors
6 | Snip and Style Classes
7 | Editor Classes
8 | Editor Functions
9 | WXME Decoding
10 | Preferences
11 | Dynamic Loading
12 | Startup Actions
13 | Init Libraries
14 | Platform Dependencies
| Index

On this page:

gui-available?
gui-dynamic-require

top contents ← prev up next →

## 11 Dynamic Loading🔗ℹ

(require racket/gui/dynamic) | package: base

The racket/gui/dynamic library provides functions for dynamically accessing the racket/gui/base library, instead of directly requiring racket/gui or racket/gui/base.

> procedure (gui-available?) → boolean?

Returns #t if dynamic access to the GUI bindings is available. The bindings are available if racket/gui/base has been loaded, instantiated, and attached to the namespace in which racket/gui/dynamic was instantiated.

> procedure (gui-dynamic-require sym) → any
> sym : symbol?

Like dynamic-require, but specifically to access exports of racket/gui/base, and only when (gui-available?) returns true.

The gui-dynamic-require function is intended primarily for use under a (gui-available?) conditional. It can also be used as a shorthand for dynamic-require with 'racket/gui/base, but only after ensuring that the bindings are available. One way to make racket/gui/base bindings available, so that (gui-available?) returns true, is through dynamic-require:

> (dynamic-require 'racket/gui/base #f)

Unlike require, using dynamic-require delays the instantiation of racket/gui/base until the run-time call of dynamic-require. With racket/gui/base so declared, gui-dynamic-require can be used to access bindings:

> (define window (new (gui-dynamic-require 'frame%)
> [label "Frame"]))
> (send window show #t)

top contents ← prev up next →