4-28-2011

Short Description: RPL Palette, Function Lists: Added function visiblity option
Bug Number: n/a
Release notes (y/n): YES
For Release Nums: 6.1

Enhancements to the RPL Palette Dialog, Function Tabs/Lists:

 (1) Added a toggle (to each tab, synchronized states) to either show or
      hide the Functions which do NOT have the return type of the selected 
      RPL expression:

  [X] Show only functions with a return type matching the selected expression.

 (2) In the Predefined Functions tab, when that checkbox is off, show all 
      predefined functions even if no RPL expression is selected.  

See Screenshots:
  http://cadswes2.colorado.edu/~philw/2011/Qt4Port/April/RplPaletteDlg/

The implementation of the second feature needs to use SOME RPL Set from which
to enumerate the Predefined Functions.  For this, a new static method in the 
RplSet class was created to return an arbitrary, existing RPL Set.  That RPL
Set is used if no RPL expression (in a RPL Editor) is currently selected.

--------------------------
QtRpl/RplPaletteDlg.hpp
QtRpl/RplPaletteDlg.cpp
QtRpl/RplPaletteWidgets.ui
--------------------------

The two new checkboxes are synchronized via a checkable QAction. That 
QAction isn't otherwise deployed (e.g. as a checkable menu item), but 
it could be. (No additional code would be necessary to keep the checkboxes
in sync with the checkable menu item).

New widgets (in UI file):
  QCheckBox* _ui._hideIncompatFuncs_userCheckBox;
  QCheckBox* _ui._hideIncompatFuncs_predefCheckBox;

Other new fields:
  QAction* _hideIncompatFuncs_toggleAction;
  const void* _predefFuncTreeViewBuiltWithRplSet; // RplSet*, no dereference

New Qt slots (signal handlers):
  void hideIncompatFuncs_toggleAction_toggled (bool);
  void hideIncompatFuncs_userCheckBox_stateChanged (int);
  void hideIncompatFuncs_predefCheckBox_stateChanged (int);

New methods:
  bool hideIncompatibleFuncs() const;

--------------
Rpl/RplSet.hpp
Rpl/RplSet.cpp
--------------

New public static method:
  static RplSet* anyRplSet();

... returns the first element of the _allRplSets vector, if it is not empty.

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