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gui-available?
gui-dynamic-require
Version: 4.2.1

4 Dynamic Loading

The scheme/gui/dynamic library provides functions for dynamically accessing the PLT Scheme GUI toolbox, instead of directly requiring scheme/gui or scheme/gui/base.

Returns #t if dynamic access to the GUI bindings are available – that is, that the program is being run as a mred-based application, as opposed to a pure mzscheme-based application, and that GUI modules are attached to the namespace in which scheme/gui/dynamic was instantiated.

This predicate can be used in code that optionally uses GUI elements when they are available.

(gui-dynamic-require sym)  any
  sym : symbol?
Like dynamic-require, but specifically to access exports of scheme/gui/base.