class TPython

                          Python interpreter access


 The TPython class allows for access to python objects from Cling. The current
 functionality is only basic: ROOT objects and builtin types can freely cross
 the boundary between the two interpreters, python objects can be instantiated
 and their methods can be called. All other cross-coding is based on strings
 that are run on the python interpreter.

 Examples:

  $ cat MyPyClass.py
  print 'creating class MyPyClass ... '

  class MyPyClass:
     def __init__( self ):
        print 'in MyPyClass.__init__'

     def gime( self, what ):
        return what

  $ root -l
  // Execute a string of python code.
  root [0] TPython::Exec( "print \'Hello World!\'" );
  Hello World!

  // Create a TBrowser on the python side, and transfer it back and forth.
  // Note the required explicit (void*) cast!
  root [1] TBrowser* b = (void*)TPython::Eval( "ROOT.TBrowser()" );
  root [2] TPython::Bind( b, "b" );
  root [3] b == (void*) TPython::Eval( "b" )
  (int)1

  // Builtin variables can cross-over by using implicit casts.
  root [4] int i = TPython::Eval( "1 + 1" );
  root [5] i
  (int)2

  // Load a python module with a class definition, and use it. Casts are
  // necessary as the type information can not be otherwise derived.
  root [6] TPython::LoadMacro( "MyPyClass.py" );
  creating class MyPyClass ...
  root [7] MyPyClass m;
  in MyPyClass.__init__
  root [8] std::string s = (char*)m.gime( "aap" );
  root [9] s
  (class TString)"aap"

 It is possible to switch between interpreters by calling "TPython::Prompt()"
 on the Cling side, while returning with ^D (EOF). State is preserved between
 successive switches.

 The API part provides (direct) C++ access to the bindings functionality of
 PyROOT. It allows verifying that you deal with a PyROOT python object in the
 first place (ObjectProxy_Check for ObjectProxy and any derived types, as well
 as ObjectProxy_CheckExact for ObjectProxy's only); and it allows conversions
 of void* to an ObjectProxy and vice versa.

Function Members (Methods)

public:

virtual	~TPython()
static Bool_t	Bind(TObject* object, const char* label)
static TClass*	Class()
static const TPyReturn	Eval(const char* expr)
static Bool_t	Exec(const char* cmd)
static void	ExecScript(const char* name, int argc = 0, const char** argv = 0)
virtual TClass*	IsA() const
static void	LoadMacro(const char* name)
static Bool_t	MethodProxy_Check(PyObject* pyobject)
static Bool_t	MethodProxy_CheckExact(PyObject* pyobject)
static void*	ObjectProxy_AsVoidPtr(PyObject* pyobject)
static Bool_t	ObjectProxy_Check(PyObject* pyobject)
static Bool_t	ObjectProxy_CheckExact(PyObject* pyobject)
static PyObject*	ObjectProxy_FromVoidPtr(void* addr, const char* classname, Bool_t python_owns = kFALSE)
TPython&	operator=(const TPython&)
static void	Prompt()
virtual void	ShowMembers(TMemberInspector& insp) const
virtual void	Streamer(TBuffer&)
void	StreamerNVirtual(TBuffer& ClassDef_StreamerNVirtual_b)
	TPython()
	TPython(const TPython&)

private:

static Bool_t

Initialize()

Class Charts

Inheritance Inherited Members Includes Libraries

Function documentation

Bool_t Initialize()

 Private initialization method: setup the python interpreter and load the
 ROOT module.

void LoadMacro(const char* name)

 Execute the give python script as if it were a macro (effectively an
 execfile in __main__), and create Cling equivalents for any newly available
 python classes.

void ExecScript(const char* name, int argc = 0, const char** argv = 0)

 Execute a python stand-alone script, with argv CLI arguments.

 example of use:
    const char* argv[] = { "1", "2", "3" };
    TPython::ExecScript( "test.py", sizeof(argv)/sizeof(argv[0]), argv );

Bool_t Exec(const char* cmd)

 Execute a python statement (e.g. "import ROOT").

const TPyReturn Eval(const char* expr)

 Evaluate a python expression (e.g. "ROOT.TBrowser()").

 Caution: do not hold on to the return value: either store it in a builtin
 type (implicit casting will work), or in a pointer to a ROOT object (explicit
 casting to a void* is required).

Bool_t Bind(TObject* object, const char* label)

 Bind a ROOT object with, at the python side, the name "label".

void Prompt()

 Enter an interactive python session (exit with ^D). State is preserved
 between successive calls.

Bool_t ObjectProxy_Check(PyObject* pyobject)

 Test whether the type of the given pyobject is of ObjectProxy type or any
 derived type.

Bool_t ObjectProxy_CheckExact(PyObject* pyobject)

 Test whether the type of the given pyobject is ObjectProxy type.

Bool_t MethodProxy_Check(PyObject* pyobject)

 Test whether the type of the given pyobject is of MethodProxy type or any
 derived type.

Bool_t MethodProxy_CheckExact(PyObject* pyobject)

 Test whether the type of the given pyobject is MethodProxy type.

void* ObjectProxy_AsVoidPtr(PyObject* pyobject)

 Extract the object pointer held by the ObjectProxy pyobject.

PyObject* ObjectProxy_FromVoidPtr(void* addr, const char* classname, Bool_t python_owns = kFALSE)

 Bind the addr to a python object of class defined by classname.

virtual ~TPython()

{ }