Python Programming On Win32

Accessing Delphi’s Visual Component Library

If you are creating a Python script to be run from a command prompt, it’s perfectly feasible to write GUI code in Delphi. The DLL could contain forms and dialogs, which can be launched from within a DLL function called by Python. One use for this might be to provide stock dialogs for a Python script, although you could go further and write an entire application that is launched from Python and uses a Delphi GUI.

For reasons discussed in Chapter 20, don’t try to run DLLs that use a GUI within the PythonWin editor. Plain-vanilla Object Pascal extensions are safe to use in any Python IDE, but the Delphi VCL application framework and the MFC application framework in PythonWin will both assume they are running the application and so, you get an immediate error message.

The authors of the package have also written their own Python IDE in Delphi and a tool that automatically examines Pascal source code and generates Python wrappers for the entire Visual Component Library. These make it possible to write Python code that creates Delphi forms and objects and accesses their methods and properties, just as you would in Delphi. The following is valid Python code:

from Forms import *
from StdCtrls import *

f = TForm().CreateNew(Application)

Unfortunately, this incredible capability is still experimental and limited to use within Delphi applications; thus, you can write a Delphi application with an embedded Python macro language that can create and manipulate ...