SAP R/3 automation with win32com

[obou at my-deja.com]

In article <90icc6022q9 at news2.newsguy.com>,
  "Alex Martelli" <aleaxit at yahoo.com> wrote:
> <obou at my-deja.com> wrote in message news:90i6n6$hg0
$1 at nnrp1.deja.com...
>     [snip]
> > I don't know VB at all and don't really know how to translate VB
> > functions calls to Python function calls. Especially when using COM.
> > There are some strange differences. In my example, there are in VB
> > function calls that takes 3 parameters where in Python I have to put
> > only 2 parameters in the brackets and get the third as a return
value.
> > The salesOrd.DimAs function calls are such cases. In VB the return
> > value is written as a third parameter and the function has no return
> > value.
> > Is there a way to identify which parameter have to stay in the
brackets
> > and which ones will be sent as return value?
>
> Yes.
>
> COM parameters are defined as [in], [out], [out,retval], or [in,out]
> (there are also other attributes, but these are the ones that matter
> here).  The [out,retval], if present at all, is only the last one.
>
> In VB, a parameter [out,retval] appears as a return value, all others
> appear as actual parameters to the function call (and not as returns).
>
> In Python, parameters [in] and [in,out] appear as actual parameters
> to the function call; parameters [out], [out,retval], and [in,out]
> appear as return values (once you've run makepy on the type library
> to let Python know what is what -- otherwise, [out] and [in,out]
> can be troublesome).  Note that [in,out] is BOTH an actual parameter
> (for the 'in' part) AND a return value (for the 'out' part).
>
> [out] and [in,out] are not all that common in well-designed COM
> (Automation) type-libraries, but, they do happen at times.
>
> The VB Object Browser does not clearly display the attributes of
> the parameters.  *However*, another precious tool is called "OLE
> View" and should be also part of VB's higher editions (and I
> think oleview.exe is also one of the tools you can download for
> free as part of Microsoft's "Platform SDK").  THAT one, OleView,
> lets you display any type-library in terms of IDL, the Interface
> Definition Language, which includes the [in], [out], etc,
> notations.  It's a very good tool for exploring COM stuff.  Of
> course, a component's docs SHOULD include the non-trifling
> details of what parameters are input ones, which are output
> ones, etc, etc, but, sometimes, such little crucial things
> drop by the wayside... and OleView can save your life then!-)
>
> Alternatively, if you'd rather read Python than IDL, look at
> the source-file that makepy.py generates for you when you 'hook
> up' to a type-library.  It's placed in win32com\genpy, and its
> filename is the GUID of the library; in the Python classes it
> builds to correspond to each COM interface, it also clearly
> separates and distinguishes between input and output parameters
> of each method.
>
> Alex
>
>

Thanks for these very helpful and precise informations!

As I have VB installed, I'll have a look at the Ole View tool.

I abuse, but is there a way to find the "Makepy" name of a particular
COM object? I have tons of SAP objects in Makepy and cannot find one
that correspond to the objects I'm using...
Do somebody know where Makepy looks for the titles it shows in it's
listbox?

Olivier Boudry


Sent via Deja.com http://www.deja.com/
Before you buy.