In the last chapter we built a number of Python classes that let us do some useful work in the financial domain, assuming we were happy to work at a command prompt and write our own scripts. Now we’ll embed this in a traditional GUI by exposing the Python classes as COM servers that provide an engine.
You can imagine a whole family of applications based on our classes,
each specialized for a specific task such as viewing and editing
BookSets, generating forecasts and
laying out reports. What you need first is a browser for your sets of
accounts that can show the same types of views as the command-line
version: lists of accounts, details of any account, and a
date-ordered “journal.” It should also allow you to edit
existing transactions and add new ones.
Our example browser is written in Visual Basic (VB) 6. We cover only a
small selection of the features and code, but the full application is
available with the code examples at
We have also built a cut-down version of the browser in
Delphi; a small
section at the end of the chapter explains the differences when using
Delphi as a client language. Most mainstream development environments
support COM, so you should be able to easily adapt what follows to
your favorite development environment.