Function: _def_readline
Class: default
Section: default
C-Name: sd_readline
Prototype:
Help:
Doc: switches readline line-editing
 facilities on and off. This may be useful if you are running \kbd{gp} in a Sun
 \tet{cmdtool}, which interacts badly with readline. Of course, until readline
 is switched on again, advanced editing features like automatic completion
 and editing history are not available.

 The default value is \kbd{1}.
