lisp-text

Class and Control

Like an editable-text control, except that the value may be any lisp object rather than a string only. When the control's value is set programmatically to a new arbitrary lisp object, the on-print event handler function for the control takes the object as its argument and should return a string to be displayed in the control. When the end user types into the control, read-from-string is called internally on the new string to produce a new arbitrary lisp object that is then stored as the value of the control. Errors are trapped during the reading so that no break will occur; if an error is signaled during the reading then nil is stored as the value of the control.

A diagram of window and widget classes is shown in Widget and window classes in cgide.htm.

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This page was not revised from the 8.1 page.
Created 2010.1.21.