Question

I would like to write a VBA diff program in (preferably) Python. Is there a Python library that will allow me to read the VBA contained in an Excel spreadsheet?

Answer 1

Here’s some quick and dirty boilerplate to get you started. It uses the Excel COM object (a Windows only solution):

from win32com.client import Dispatch
wbpath = 'C:\\example.xlsm'
xl = Dispatch("Excel.Application")
xl.Visible = 1
wb = xl.Workbooks.Open(wbpath)
vbcode = wb.VBProject.VBComponents(1).CodeModule
print vbcode.Lines(1, vbcode.CountOfLines)

This prints the silly macro I recorded for this example:

Sub silly_macro()
'
' silly_macro Macro
'

'
    Range("B2").Select
End Sub

Note that Lines and VBComponents use 1-based indexing. VBComponents also supports indexing by module name. Also note that Excel requires backslashes in paths.

To dive deeper see Pearson’s Programming The VBA Editor. (The above example was cobbled together from what I skimmed from there.)