Wx::NewClass(3) User Contributed Perl Documentation Wx::NewClass(3)NAME
NewClass - adding a new class to wxPerl
CHECKLIST
· Are there constants or events that need to be wrapped?
see "CONSTANTS" and "EVENTS".
· Is the class is derived from wxObject, from wxEvtHandler or from
another class?
see "CHOOSING A TYPEMAP".
· Are class instances destroyed by wxWidgets or should they be
garbage collected like normal Perl objects?
see "DESTRUCTORS AND THREADS".
· Does the class have overloaded methods?
see "OVERLOADING".
· Does the class have virtual methods that should be overridable from
Perl?
see "VIRTUAL METHODS".
SKELETON
Add a new file XS/NewClass.xsp and update the MANIFEST. Choose a
relevant .xs file in the top level directory (eg. Controls.xs) and add
this line:
INCLUDE_COMMAND: $^X -MExtUtils::XSpp::Cmd -e xspp -- -t typemap.xsp XS/NewClass.xsp
A skeleton for NewClass.xsp:
%module{Wx};
#include <wx/newclass.h> // use the relevant wxWidgets header(s)
%name{Wx::NewClass} class wxNewClass : public wxSomeBaseClass
{
# constructors see the CONSTRUCTORS section
wxNewClass( wxWindow* some_window, const wxString& str );
# destructors
~wxNewClass();
# methods
wxString GetString() const;
void SetString( const wxString& str );
};
Add the typemap definition to typemap.tmpl. See "CHOOSING A TYPEMAP".
If adding a class related to one of the wxPerl submodules
("Wx::RichText", "Wx::Html", ...) add the .xsp file to the relevant
subdirectory and modify the .xs and typemap files in that subdirectory.
CHOOSING A TYPEMAP
There are five typemaps that should work for most wxWidgets objects:
· "O_NON_WXOBJECT"
for all classes that do not derive from "wxObject" AND do not need
to be garbage collected.
· "O_NON_WXOBJECT_THR"
for all classes that do not derive from "wxObject" AND need to be
garbage collected (see "DESTRUCTORS AND THREADS").
· "O_WXOBJECT"
for all classes that derive from "wxObject" AND do not need to be
garbage collected.
· "O_WXOBJECT_THR"
for all classes derived from "wxObject" AND need to be garbage
collected (see "DESTRUCTORS AND THREADS").
· "O_WXEVTHANDLER"
for all classes that derive from "wxEvtHandler". See also
"CONSTRUCTORS".
CONSTRUCTORS
For "O_WXEVTHANDLER" typemaps, there is some additional code that needs
to be added to the constructor:
wxNewClass( wxWindow* some_window, const wxString& str )
%code{% RETVAL = new wxNewClass( some_window, str );
wxPli_create_evthandler( aTHX_ RETVAL, CLASS );
%};
DESTRUCTORS AND THREADS
For many classes not derived from "wxEvtHandler" you need to add a
destructor to free the C++ object when the Perl object is garbage
collected. At the XS++ level this means adding
~wxNewClass();
to the class definition, but there is a catch: the Perl threading
model.
Without going into details, this is needed for Perl threads
compatibility:
· Use the correct typemap
choose either "O_NON_WXOBJECT_THR" or "O_WXOBJECT_THR".
· Implement a "CLONE" method
add this code inside the class declaration:
%{
static void
wxNewClass::CLONE()
CODE:
wxPli_thread_sv_clone( aTHX_ CLASS, (wxPliCloneSV)wxPli_detach_object );
%}
· Fix the destructor.
modify the destructor like this:
~wxNewClass()
%code%{ wxPli_thread_sv_unregister( aTHX_ "Wx::NewClass", THIS, ST(0) );
delete THIS;
%};
VIRTUAL METHODS
The wrapping of virtual functions whose arguments are simple C++ types
(integrals, bool, floating point) and common wxWidgets types (wxString)
should be automatic: at the top of the file, load the plugin that
handles virtual methods
%loadplugin{build::Wx::XSP::Virtual};
and decorate virtual/pure virtual methods using the %Virtual directive
// pure virtual
virtual wxString GetTitle() const = 0 %Virtual{pure};
// virtual, not pure
virtual int GetBestFittingWidth(unsigned int idx) const %Virtual;
If the class contains pure virtual methods, it will be marked as
abstract, and it will have no constructors.
For abstract classes, XS++ will create an additional Perl-level class,
called "Wx::Pl<classname>"; in order to override the virtual methods,
you must derive from this class, and not from "Wx::<classname>".
TODO allow changing the default behaviour for abstract/concrete classes
TODO allow overriding the class name
TODO allow specifying custom code
TODO handle multiple return values
TODO customized type mapping
perl v5.14.3 2010-06-07 Wx::NewClass(3)
