[Python-Dev] Install-on-first-use vs. optional extensions (original) (raw)

Guido van Rossum gvanrossum at gmail.com
Wed Sep 8 06:53:52 CEST 2004

On Wed, 08 Sep 2004 06:41:28 +0200, Martin v. Löwis <martin at v.loewis.de> wrote:

I recently looked into properly implementing the "Register Extensions" feature in the installer; in 2.4a3, not selecting that doesn't really work. The problem is that MSI only supports installing either both the "extension server" (the .exe) and the extension, or neither. So you can chose not to install word.exe, and it won't install the .doc extension; if you install word.exe, it will associate .doc with it.

For Python, this leaves us with three options: 1. Don't make registration of extensions optional; always associate .py, .pyc, .pyw, .pyo. 2. Don't support installation-on-demand for extensions. This means to not use the MSI extension machinery at all, but to directly write the registry keys that build the extension. Installing these keys can then be made optional. 3. Provide another binary that is the "extension server", and install that independently of python.exe, and pythonw.exe. In CVS, I have implemented this approach to see whether it works (it does), and called this binary "launcher.exe". It is a Windows app which supports a -console argument which also makes it a console app. This is the the binary that gets associated with all four extensions, for the "open" verb. Currently, I'm in favour of using option 3, but I'd like to hear whether people would prefer something else instead. Regards, Martin

I frequently use the extension feature in a console context; when I am in a directory full of .py files, I can run any one of them by simply typing its name (and possibly command line arguments). The script will then interact through the existing console window. WIll this work?

From your description I fear that this would start the script without console I/O possibility or in a separate window, both of which would make this a no-no. If you can confirm that this works as expected, I think the separate driver is fine, since pretty much by definition you can't pass any command line arguments to Python (although I would hope that the environment variables would still work).

-- --Guido van Rossum (home page: http://www.python.org/~guido/) Ask me about gmail.

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