library: libPyROOT
#include "TPython.h"


class description - source file - inheritance tree (.pdf)

class TPython

Inheritance Chart:
static Bool_t Initialize() public:
TPython() TPython(const TPython&) virtual ~TPython() static Bool_t Bind(TObject* object, const char* label) static TClass* Class() static const TPyReturn Eval(const char* expr) const static void Exec(const char* cmd) virtual TClass* IsA() const static void LoadMacro(const char* name) TPython& operator=(const TPython&) static void Prompt() virtual void ShowMembers(TMemberInspector& insp, char* parent) virtual void Streamer(TBuffer& b) void StreamerNVirtual(TBuffer& b)

Data Members

Class Description

                          Python interpreter access

 The TPython class allows for access to python objects from CINT. 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.


  $ cat
  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" )

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

  // Load a python module with a class definition, and use it.
  root [6] TPython::LoadMacro( "" );
  creating class MyPyClass ...
  root [7] MyPyClass m;
  in MyPyClass.__init__
  root [8] char* s = m.gime( "aap" );
  root [9] s
  (char* 0x41ee7754)"aap"

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

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 CINT equivalents for any newly available
 python classes.

void 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.

Inline Functions

               void ~TPython()
            TClass* Class()
            TClass* IsA() const
               void ShowMembers(TMemberInspector& insp, char* parent)
               void Streamer(TBuffer& b)
               void StreamerNVirtual(TBuffer& b)
            TPython TPython()
            TPython TPython(const TPython&)
           TPython& operator=(const TPython&)

Author: Wim Lavrijsen, Apr 2004
Last update: root/pyroot:$Name: $:$Id: TPython.cxx,v 1.12 2005/09/09 05:19:10 brun Exp $

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