Subject: Re: registered file extensions on win32

From: Jan Wielemaker <[email-masked]>
Date: Tue, 29 Feb 2000 10:20:44 +0100

>       .pl is registered by Perl script engines 
>       (ActivePerl, Win32Perl). SWI installed from 
>       binary package registers this extension 
>       for itself, rendering perl totally unusable.
>       
> This was sheer bad manners by the Perl people; Prolog was there
> first, and if they had used '.pe' we'd have had no problem at all.
> 
> In order to keep various Prolog dialects apart, it is already
> convenient to use different file type strings, such as '.swi'.
> There's no way a solution devised here can be forced on other
> Prolog suppliers, so how about '.swi'?

I think the real person with bad manners is Billy.  As long as
extensions had only informal meaning there was no problem, and Perl
and Prolog (any brand) could more or less happily use the same
extension, only causing some pain to somebody writing a program
partially in Perl and partially in Prolog.

Microsoft has given extensions a real meaning next of whatever the
application thinks about extensions.  The nice click-to-open based
on extension caused a complete war on extensions, without a jury.

They should have done something along the line of file-attributes,
leaving the meaning of extensions a hint to the user and possibly
meaningful to the application.

On the other hand, we have to live with it.  It is a pitty that, now
we finally a Prolog standard, we give our files vendor-specific
extensions.  I will consider providing an option in the installation
script using .swi as an alternative to .pl.

Prolog will keep looking for .pl files in addition to .swi files in
that case, so we can keep the name .pl in the libraries.

Good that our department has such a nice acronym :-)

        Regards --- Jan