[pygccxml-commit] SF.net SVN: pygccxml: [678] pyplusplus_dev/docs/bpl_lessons_learned/ smart_ptrs/generate_code.py

[<rom...@us...>]

Revision: 678
          http://svn.sourceforge.net/pygccxml/?rev=678&view=rev
Author:   roman_yakovenko
Date:     2006-10-19 01:24:18 -0700 (Thu, 19 Oct 2006)

Log Message:
-----------
adding Py++ code, which shows how to exposes the example

Added Paths:
-----------
    pyplusplus_dev/docs/bpl_lessons_learned/smart_ptrs/generate_code.py

Added: pyplusplus_dev/docs/bpl_lessons_learned/smart_ptrs/generate_code.py
===================================================================
--- pyplusplus_dev/docs/bpl_lessons_learned/smart_ptrs/generate_code.py	                        (rev 0)
+++ pyplusplus_dev/docs/bpl_lessons_learned/smart_ptrs/generate_code.py	2006-10-19 08:24:18 UTC (rev 678)
@@ -0,0 +1,120 @@
+#The code contained in this file will show you how to instruct Py++ to generate 
+#code, that uses your smart pointer class.
+#
+
+#Advise:
+#Using your favorite editor create regular C++ header file and to it next code.
+#You don't really need to generate it every time.
+#
+# template<class T>
+# inline T * get_pointer(smart_ptr_t<T> const& p){
+#     return p.get();
+# }
+#
+# template <class T>
+# struct pointee< smart_ptr_t<T> >{
+#     typedef T type;
+# };
+
+
+HELD_TYPE_TMPL = \
+"""
+namespace boost{ namespace python{
+
+%(class_name)s* get_pointer( %(class_ptr_name)s const& p ){
+    return p.get();
+}
+
+template <>
+struct pointee< %(class_ptr_name)s >{
+    typedef %(class_name)s type;
+};
+
+}}// namespace boost::python
+"""
+
+REGISTER_PTR_TO_PYTHON_TMPL = \
+"""
+boost::python::register_ptr_to_python< %(sp_inst_class_name)s >();
+"""
+
+IMPLICITLY_CONVERTIBLE_TMPL = \
+"""
+boost::python::implicitly_convertible< %(derived)s, %(base)s >();
+"""
+
+
+def get_pointee( sp_instantiation ):
+    #sp_instantiation - reference to smart_ptr_t<XXX>
+    #returns reference to XXX type/declaration
+    #I will find m_managed member variable and will find out its type
+    no_ptr = declarations.remove_pointer( sp_instantiation.variable ('m_managed').type )
+    no_alias = declarations.remove_alias( no_ptr )
+    return declarations.remove_declarated( no_alias )
+
+def expose_single( sp_instantiation ):
+    #This function instructs Py++ how to expose pointee class functionality
+    #related to your smart pointer
+    #sp_instantiation - reference to smart_ptr_t<XXX>
+    
+    # You don't need to expose smart_ptr_t< X > class
+    sp_instantiation.exclude() 
+
+    pointee = get_pointee( sp_instantiation )
+    
+    #Our example defines derived_ptr_t class:
+    #struct derived_ptr_t : public smart_ptr_t< derived_t >
+    #{...};
+    #Next if checks that smart_ptr_t< XXX > class has a derived class
+    #and "exposes" it.
+    if sp_instantiation.derived:
+        assert 1 == len( sp_instantiation.derived )
+        sp_derived = sp_instantiation.derived[0].related_class
+        #You don't want to expose it
+        sp_derived.exclude()
+
+        #Adding your custom code to pointee class. 
+        #You don't have to warry about order or place of generated code,
+        #Py++ does it right.
+        
+        #Telling Boost.Python how to work with your smart pointer
+        pointee.add_declaration_code(
+            HELD_TYPE_TMPL % { 'class_name': pointee.decl_string
+                                       , 'class_ptr_name': sp_derived.decl_string } )
+
+        #Telling Boost.Python about relationship between classes
+        pointee.add_registration_code(
+            IMPLICITLY_CONVERTIBLE_TMPL % { 'derived' : sp_derived.decl_string
+                                         , 'base' : sp_instantiation.decl_string }
+            , works_on_instance=False )
+
+        pointee.add_registration_code(
+            REGISTER_PTR_TO_PYTHON_TMPL % { 'sp_inst_class_name' : sp_derived.decl_string }
+            , works_on_instance=False )
+
+    #Setting class held type
+    pointee.held_type = 'smart_ptr_t< %s >' % pointee.wrapper_alias
+    
+    #Registering relationships between classes
+    pointee.add_registration_code(
+        IMPLICITLY_CONVERTIBLE_TMPL % { 'derived' : pointee.held_type
+                                     , 'base' : sp_instantiation.decl_string }
+        , works_on_instance=False )
+
+    pointee.add_registration_code(
+        REGISTER_PTR_TO_PYTHON_TMPL % { 'sp_inst_class_name' : sp_instantiation.decl_string }
+        , works_on_instance=False )
+
+    #Registering relationships between classes
+    base_classes = filter( lambda hierarchy_info: hierarchy_info.access_type == 'public', pointee.bases )
+    for base in base_classes:
+        pointee.add_registration_code(
+            IMPLICITLY_CONVERTIBLE_TMPL % { 'derived' : sp_instantiation.decl_string
+                                         , 'base' : 'smart_ptr_t< %s >' % base.related_class.decl_string }
+            , works_on_instance=False)
+
+def expose(mb):
+    sp_instantiations = mb.classes( lambda decl: decl.name.startswith( 'smart_ptr_t' ) )
+    map( lambda sp: expose_single( sp ), sp_instantiations )
+
+


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