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From: <rom...@us...> - 2008-01-05 21:19:41
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Revision: 1220
http://pygccxml.svn.sourceforge.net/pygccxml/?rev=1220&view=rev
Author: roman_yakovenko
Date: 2008-01-05 13:19:44 -0800 (Sat, 05 Jan 2008)
Log Message:
-----------
moving docs
Removed Paths:
-------------
pyplusplus_dev/docs/documentation/best_practices.rest
pyplusplus_dev/docs/documentation/hints.rest
pyplusplus_dev/docs/documentation/how_to.rest
Deleted: pyplusplus_dev/docs/documentation/best_practices.rest
===================================================================
--- pyplusplus_dev/docs/documentation/best_practices.rest 2008-01-05 21:18:15 UTC (rev 1219)
+++ pyplusplus_dev/docs/documentation/best_practices.rest 2008-01-05 21:19:44 UTC (rev 1220)
@@ -1,176 +0,0 @@
-==============
-Best practices
-==============
-
-.. contents:: Table of contents
-
-------------
-Introduction
-------------
-
-`Py++`_ has reach interface and a lot of functionality. Sometimes reach
-interface helps, but sometimes it can confuse. This document will describe how
-effectively to use `Py++`_.
-
-------------
-Big projects
-------------
-
-Definition
-----------
-
-First of all, let me to define "big project". "Big project" is a project with
-few hundred of header files. `Py++`_ was born to create `Python`_ bindings
-for such projects. If you take a look `here`__ you will find few such projects.
-
-.. __ : ./../../pyplusplus/quotes.html
-
-Tips
-----
-
-* Create one header file, which will include all project header files.
-
- Doing it this way makes it so `GCC-XML`_ is only called once and it reduces the
- overhead that would occur if you pass `GCC-XML`_ all the files individually.
- Namely `GCC-XML`_ would have to run hundreds of times and each call would
- actually end up including quite a bit of common code anyway. This way takes a
- `GCC-XML`_ processing time from multiple hours with gigabytes of caches to a
- couple minutes with a reasonable cache size.
-
- You can read more about different caches supported by `pygccxml`_ `here`__.
- ``module_builder_t.__init__`` method takes reference to an instance of cache
- class or ``None``:
-
- .. code-block:: Python
-
- from module_builder import *
- mb = module_builder_t( ..., cache=file_cache_t( path to project cache file ), ... )
-
-* Single header file, will also improve performance compiling the generated bindings.
-
- When `Py++`_ generated the bindings, you have a lot of .cpp files to
- compile. The project you are working on is big. I am sure it takes a lot of
- time to compile projects that depend on it. Generated code also depend on it,
- more over this code contains a lot of template instantiations. So it could
- take a great deal of time to compile it. Allen Bierbaum investigated this
- problem. He found out that most of the time is really spent processing all the
- headers, templates, macros from the project and from the boost library. So he
- come to conclusion, that in order to improve compilation speed, user should
- be able to control( to be able to generate ) precompiled header file. He
- implemented an initial version of the functionality. After small discussion,
- we agreed on next interface:
-
- .. code-block:: Python
-
- class module_builder_t( ... ):
- ...
- def split_module( self, directory_path, huge_classes=None, precompiled_header=None ):
- ...
-
- ``precompiled_header`` argument could be ``None`` or string, that contains
- name of precompiled header file, which will be created in the directory.
- `Py++`_ will add to it header files from `Boost.Python`_ library and
- your header files.
-
- What is ``huge_classes`` argument for? ``huge_classes`` could be ``None`` or
- list of references to class declarations. It is there to provide a solution to
- `this error`_. `Py++`_ will automatically split generated code for the
- huge classes to few files:
-
- .. code-block:: Python
-
- mb = module_builder_t( ... )
- ...
- my_big_class = mb.class_( my_big_class )
- mb.split_module( ..., huge_classes=[my_big_class], ... )
-
- * **Caveats**
-
- Consider next file layout:
- ::
-
- boost/
- date_time/
- ptime.hpp
- time_duration.hpp
- date_time.hpp //main header, which include all other header files
-
- Py++ currently does not handle relative paths as input very well, so it is
- recommended that you use "os.path.abspath()" to transform the header file to
- be processed into an absolute path:
-
- .. code-block:: Python
-
- #Next code will expose nothing
- mb = module_builder( [ 'date_time/date_time.hpp' ], ... )
-
- #while this one will work as expected
- import os
- mb = module_builder( [ os.path.abspath('date_time/date_time.hpp') ], ... )
-
-.. _`this error` : http://boost.org/libs/python/doc/v2/faq.html#c1204
-.. __ : ./../../pygccxml/design.html
-
-* Keep the declaration tree small.
-
- When parsing the header files to build the declaration tree, there will also
- be the occasional "junk" declaration inside the tree that is not relevant to
- the bindings you want to generate. These extra declarations come from header
- files that were included somewhere in the header files that you were actually
- parsing (e.g. if that library uses the STL or OpenGL or other system headers
- then the final declaration tree will contain those declarations, too).
- It can happen that the majority of declarations in your declaration tree are
- such "junk" declarations that are not required for generating your bindings
- and that just slow down the generation process (reading the declaration cache
- and doing queries will take longer).
-
- To speed up your generation process you might want to consider making the
- declaration tree as small as possible and only store those declarations that
- somehow have an influence on the bindings. Ideally, this is done as early
- as possible and luckily gccxml provides an option that allows you to reduce
- the number of declarations that it will store in the output XML file. You can
- specify one or more declarations using the ``-fxml-start`` option and only
- those sub-tree starting at the specified declarations will be written. For
- example, if you specify the name of a particular class, only this class
- and all its members will get written. Or if your project already uses
- a dedicated namespace you can simply use this namespace as a starting point
- and all declarations stemming from system headers will be ignored (except
- for those declarations that are actually used within your library).
-
- In the ``pygccxml`` package you can set the value for the ``-fxml-start``
- option using the ``start_with_declarations`` attribute of the
- ``pygccxml.parser.config_t`` object that you are passing to the parser.
-
-* Use `Py++`_ repository of generated files md5 sum.
-
- `Py++`_ is able to store md5 sum of generated files in a file. Next time you
- will generate code, `Py++`_ will compare generated file content against the sum,
- instead of loading the content of the previously generated file from the disk
- and comparing against it.
-
- .. code-block:: Python
-
- mb = module_builder_t( ... )
- ...
- my_big_class = mb.class_( my_big_class )
- mb.split_module( ..., use_files_sum_repository=True )
-
- `Py++`_ will generate file named "<your module name>.md5.sum" in the directory
- it will generate all the files.
-
- Enabling this functionality should give you 10-15% of performance boost.
-
- * **Caveats**
-
- If you changed manually some of the files - don't forget to delete the relevant
- line from "md5.sum" file. You can also delete the whole file. If the file is
- missing, `Py++`_ will use old plain method of comparing content of the files.
- It will not re-write "unchanged" files and you will not be forced to recompile
- the whole project.
-
-
-.. _`Py++` : ./../pyplusplus.html
-.. _`pygccxml` : ./../../pygccxml/pygccxml.html
-.. _`Boost.Python`: http://www.boost.org/libs/python/doc/index.html
-.. _`Python`: http://www.python.org
-.. _`GCC-XML`: http://www.gccxml.org
Deleted: pyplusplus_dev/docs/documentation/hints.rest
===================================================================
--- pyplusplus_dev/docs/documentation/hints.rest 2008-01-05 21:18:15 UTC (rev 1219)
+++ pyplusplus_dev/docs/documentation/hints.rest 2008-01-05 21:19:44 UTC (rev 1220)
@@ -1,64 +0,0 @@
-=====
-Hints
-=====
-
-.. contents:: Table of contents
-
-----------------------------------
-Class template instantiation alias
-----------------------------------
-
-`Py++`_ has nice feature. If you define ``typedef`` for instantiated class
-template, than `Py++`_ will use it as a `Python`_ class name.
-
-For example:
-
-.. code-block:: C++
-
- #include <vector>
- typedef std::vector< int > numbers;
- numbers generate_n(){
- ...
- }
-
-`Py++`_ will use "numbers" as Python class name:
-
-.. code-block:: C++
-
- using boost::python;
- class_< std::vector< int > >( "numbers" )
- ...
- ;
-
-`Py++`_ will pick up the alias, only in case the class has single "typedef".
-
-``pyplusplus::aliases`` namespace
----------------------------------
-
-The previous approach is "implicit" - `Py++`_ does something behind the scene.
-Recently (version 0.8.6 ), another approach was introduced:
-
-.. code-block:: C++
-
- #include <vector>
-
- namespace pyplusplus{ namespace aliases{
- //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- typedef std::vector< int > numbers;
-
- } } //pyplusplus::aliases
-
-The idea is that you create namespace with a special name - ``pyplusplus::aliases``
-and `Py++`_ automatically picks the class aliases from it. In case you accidentally
-introduced two or more different aliases to the same class, it will pick the
-longest one and print a warning. Other advantages of the approach:
-
-* you are not forced to learn new API
-
-* you continue to use your favorite editor and familiar language
-
-.. _`Py++` : ./../pyplusplus.html
-.. _`Boost.Python`: http://www.boost.org/libs/python/doc/index.html
-.. _`Python`: http://www.python.org
-.. _`GCC-XML`: http://www.gccxml.org
-
Deleted: pyplusplus_dev/docs/documentation/how_to.rest
===================================================================
--- pyplusplus_dev/docs/documentation/how_to.rest 2008-01-05 21:18:15 UTC (rev 1219)
+++ pyplusplus_dev/docs/documentation/how_to.rest 2008-01-05 21:19:44 UTC (rev 1220)
@@ -1,411 +0,0 @@
-============
-How to ... ?
-============
-
-.. contents:: Table of contents
-
-----------------------------------------
-How to add custom exception translation?
-----------------------------------------
-
-.. code-block:: C++
-
- struct my_exception{
- ...
- const std::string& error() const;
- }
-
-First of all lets define ``translate`` function:
-
-.. code-block:: Python
-
- translate_code = \
- """
- void translate(const my_exception &exception){
- PyErr_SetString( PyExc_RuntimeError, exception.error().c_str() );
- }
- """
-
-.. code-block:: Python
-
- mb = module_builder_t( ... )
- mb.add_declaration_code( translate_code )
-
-
-Now we should register it:
-
-.. code-block:: Python
-
- registration_code = "boost::python::register_exception_translator<my_exception>(&translate);"
- mb.add_registration_code( registration_code )
-
-Small usage advice.
--------------------
-
-`Py++`_ allows you to define a query that will return you all exception classes:
-
-.. code-block:: Python
-
- mb = module_builder_t( ... )
- exception_classes = mb.decls( lambda decl: decl.name.endswith( 'exception' ) )
-
-Now you can iterate on ``exception_classes``, generate and register translate
-code for every class.
-
-That's all.
-
--------------------------------------------------------
-How to expose function, which has hand-written wrapper?
--------------------------------------------------------
-.. code-block:: C++
-
- struct window_t{
- ...
- void get_size( int& height, int& widht ) const;
- };
-
-You can not expose ``get_size`` function as is - ``int`` is immutable type in
-Python. So, we need to create a wrapper to the function:
-
-.. code-block:: C++
-
- boost::python::tuple get_size_wrapper( const window_t& win ){
- int height(0), width( 0 );
- win.get_size( height, widht );
- return boost::python::make_tuple( height, width );
- }
-
-.. code-block:: C++
-
- class_<window_t>( ... )
- .def( "get_size", &get_size_wrapper )
- ...
- ;
-
-Now, after you know how this problem is solved. I will show how this solution
-could be integrated with `Py++`_.
-
-.. code-block:: Python
-
- wrapper_code = \
- """
- static boost::python::tuple get_size( const window_t& win ){
- int height(0), width( 0 );
- win.get_size( height, width );
- return boost::python::make_tuple( height, width );
- }
- """
-
-.. code-block:: Python
-
- registration_code = 'def( "get_size", &%s::get_size )' % window.wrapper_alias
-
-.. code-block:: Python
-
- mb = module_builder_t( ... )
- window = mb.class_( "window_t" )
- window.member_function( "get_size" ).exclude()
- window.add_wrapper_code( wrapper_code )
- window.registration_code( registration_code )
-
-That's all.
-
--------------------------------------------------------------
-Fatal error C1204:Compiler limit: internal structure overflow
--------------------------------------------------------------
-
-If you get this error, than the generated file is too big. You will have to split
-it to few files. Well, not you but `Py++`_, you will only have to tell it to do
-that.
-
-If you are using ``module_builder_t.write_module`` method, consider to switch
-to ``module_builder_t.split_module``.
-
-If you are using ``split_module``, but still the generated code for some class
-could not be compiled, because of the error, you can ask `Py++`_ to split the
-code generated for class to be split to few cpp files.
-
-For more information, please read the documentation.
-
-------------------------------------------------------
-How to automatically export template functions\\class?
-------------------------------------------------------
-
-Lets say you have next C++ function:
-
-.. code-block:: C++
-
- // file point.h
- namespace geometry{
- template< class T>
- struct point_t{
- T x, y;
- };
- template <class T>
- double distance( const point_t<T>& point ){
- return sqrt( point.x * point.x + point.y*point.y );
- }
- } //namespace geometry
-
-You should understand, that you can not export template itself, but only its
-instantiations. The solution is built using next facts:
-
-* ``sizeof( class name )`` causes a compiler to instantiate the class
-
-* free function invocation causes a compiler to instantiate the function
-
-Lets say that we need to export the class and the function template
-instantiations for ``int`` and ``custom_type`` types. There are few ways to do it.
-
-Simple and straightforward
---------------------------
-
-Open your favourite editor and create a header file with the content:
-
-.. code-block:: C++
-
- #include "point.h"
-
-.. code-block:: C++
-
- namespace py_details{
- inline void instantiate(){
- using namespace geometry;
- sizeof( point_t<int> );
- sizeof( point_t<custom_type> );
- distance( point_t<int>(0,0) );
- distance( point_t<custom_type>(0,0) );
- }
- }
-
-Now, you add this file to the list of files you pass as input to
-``module_builder_t.__init__`` method and excludes the ``py_details`` namespace
-declarations from being exported:
-
-.. code-block:: Python
-
- mb = module_builder_t( [..., just created file ], ... )
- mb.namespace( 'py_details' ).exclude()
-
-"Dynamic" instantiation
------------------------
-
-Lets say you are less lucky than I, and you have to create ``X`` instantiations
-of the class\\function. Obviously, the previous approach will not work for you.
-The solution is to build your own code generator, which will generate code similar
-to the one, in the previous paragraph.
-
-.. code-block:: Python
-
- from module_builder import module_builder_t, create_text_fc
-
-.. code-block:: Python
-
- def generate_instantiations_string( ... ):
- ...
-
-.. code-block:: Python
-
- code = generate_instantiations_string( ... )
-
-.. code-block:: Python
-
- mb = module_builder_t( [ ..., create_text_fc( code ) ], ... )
- mb.namespace( 'py_details' ).exclude()
-
-
-`Py++`_ allows you to extract declarations from string, which contains
-valid C++ code. It creates temporal header file and compiles it. At the end of
-the compilation process it will remove it. You can read mode about ``create_text_fc``
-function `here`__.
-
-.. __ : ./../../pygccxml/design.html#parser-configuration-classes
-
-
-
-I understand that the provided solution is not perfect. I understand that something
-better and simpler should be done, but a priority of this is low. There are few
-tasks, that have much higher priority. Allen Bierbaum wants to fix the situation.
-He created a `wiki page`_, that discuss possible solutions. Your contribution is
-welcome too!
-
-.. _`wiki page` : https://realityforge.vrsource.org/view/PyppApi/TemplateSupport
-
----------------------------------------------------
-How to deal with template on return type functions?
----------------------------------------------------
-.. code-block:: C++
-
- struct environment_t{
- ...
- template< class T>
- T get_value(const std::string& name);
- ...
- };
-
- //Somewhere in your code
- environment_t env;
- std::string path = env.get_value< std::string >( "PATH" );
- int version = env.get_value< int >( "VERSION" );
-
-`GCC-XML`_ will see both instantiations, ``get_value<int>`` and ``get_value< std::string >``,
-and will provide information about them. The name of both member functions,
-reported by `GCC-XML`_ is "**get_value**".
-
-In this case, `Py++`_ generates a code, which contains few errors and if your are
-lucky, depends on the compiler you use, the generated code will not compile.
-Otherwise, you will discover the errors while testing the bindings.
-
-Generated code:
-
-.. code-block:: C++
-
- bp::class_< environment_t >( "environment_t" )
- ...
- .def( "get_value"
- , (int ( ::environment_t::* )( ::std::string const & ) )( &::environment_t::get_value ) )
- .def( "get_value"
- , (::std::string ( ::environment_t::* )( ::std::string const & ) )( &::environment_t::get_value ) );
-
-The correct code:
-
-.. code-block:: C++
-
- bp::class_< environment_t >( "environment_t" )
- .def( "get_value"
- , (int ( ::environment_t::* )( ::std::string const & ) )( &::environment_t::get_value< int > ) )
- //--------------------------------------------------------------------------^^^^^^^^^^^^^^^^
- .def( "get_value"
- , (::std::string ( ::environment_t::* )( ::std::string const & ) )( &::environment_t::get_value< std::string > ) );
- //------------------------------------------------------------------------------------^^^^^^^^^^^^^^^^^^^^^^^^
-
-The perfect one:
-
-.. code-block:: C++
-
- bp::class_< environment_t >( "environment_t" )
- ...
- .def( "get_value", &::environment_t::get_value< int > )
- .def( "get_value", &::environment_t::get_value< std::string > );
-
-Solution
---------
-.. code-block:: Python
-
- mb = module_builder_t( ..., optimize_queries=False, ... )
- environment = mb.class_( "environment_t" )
- for f in environment.member_functions( "get_value" ):
- f.alias = f.name + "_" + f.return_type.decl_string #create new function alias
- f.name = f.demangled_name
- mb.run_query_optimizer()
-
-Before you read the rest of the answer, you should understand what is "name mangling"
-means. If you don't, consider reading about it on `Wikipedia`__.
-
-.. __ : http://en.wikipedia.org/wiki/Name_mangling
-
-
-The solution is pretty simple. `GCC-XML`_ reports mangled and demangled function
-names. The demangled function name contains "real" function name:
-``get_value< used type >``. You only have to instruct `Py++`_ to use it.
-
-`Py++`_ does not use by default demangled function name for mainly one reason.
-Demangled function name is a string that contains a lot of information. `Py++`_
-implements a parser, which extracts the only relevant one. The parser
-implementation is a little bit complex and was not heavily tested. By "heavily" I
-mean that I tested it on a lot of crazy use cases and on a real project, but
-there is always some new use case out there. I am almost sure it will work for
-you. The problem, we deal with, is rare, so by default "demangled_name"
-feature is turned off.
-
-By the way, almost the same problem exists for template classes. But, in the
-classes use case `Py++`_ uses demangled name by default.
-
-
--------------------------------------
-Py++ generated file name is too long!
--------------------------------------
-There are use cases, when `Py++`_ generated file name is too long. In some cases
-the code generation process even fails because of this. What can you do in order
-to eliminate the problem?
-
-First of all the problem arises when you expose template instantiated classes
-and you did not set the class alias.
-
-Let me explain:
-
-.. code-block:: C++
-
- template < class T>
- struct holder{ ... };
-
-
-Lets say that you want to export ``holder< int >`` class. Class name in `Python`_
-has few `constraints`_. `Py++`_ is aware of the `constraints`_ and if you didn't
-set an alias to the class, `Py++`_ will do it for you. In this case,
-"holder_less_int_grate\_" is the generated alias. Obviously it is much longer
-and not readable.
-
-.. _`constraints` : http://www.python.org/doc/current/ref/identifiers.html
-
-There are few pretty good reasons for this behavior:
-
-* when you just start to work on `Python`_ bindings concentrate your attention
- on really important things
-
-* if you forgot to set the class alias your users still can use the class
- functionality, however the class name will be a little bit ugly.
-
-
-In this case the generate alias for ``holder`` instantiation is relatively short.
-Imagine how long it could be for ``std::map`` instantiation.
-
-`Py++`_ uses class alias for the file name. So if you want to force `Py++`_ to
-generate files with short name, you have to set class alias:
-
-.. code-block:: Python
-
- from pyplusplus import module_builder
-
- mb = module_builder_t( ... )
- holder = mb.class_( 'holder< int >' )
- holder.alias = 'IntHolder'
- #next line has same effect as the previous one:
- holder.rename( 'IntHolder' )
-
-The nice thing about this approach is that now `Python`_ users have "normal"
-class name and you have short file name.
-
--------------------
-Full\relative paths
--------------------
-
-Consider next file layout:
-::
-
- boost/
- date_time/
- ptime.hpp
- time_duration.hpp
- date_time.hpp //main header, which include all other header files
-
-Py++ currently does not handle relative paths as input very well, so it is
-recommended that you use ``os.path.abspath()`` to transform the header file to
-be processed into an absolute path:
-
-.. code-block:: Python
-
- #Next code will expose nothing
- mb = module_builder( [ 'date_time/date_time.hpp' ], ... )
- mb.split_module( ... )
-
- #while this one will work as expected
- import os
- mb = module_builder( [ os.path.abspath('date_time/date_time.hpp') ], ... )
- mb.split_module( ... )
-
-
-.. _`Py++` : ./../pyplusplus.html
-.. _`Boost.Python`: http://www.boost.org/libs/python/doc/index.html
-.. _`Python`: http://www.python.org
-.. _`GCC-XML`: http://www.gccxml.org
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