Subject: Who will write filtering scripts?

From: Tim Showalter <[email-masked]>
Date: Thu, 27 Mar 1997 16:38:57 -0500 (EST)

I'm working on a draft for a filtering language.  I have one fairly
fundamental question: should the language be geared to be machine-readable
or human-writable?  It would be far easier to write a prefix-oriented
language with lots of LISP-like syntax, but I believe most users find that
difficult to use (and it is my limited experience it's hard to balance
parens without an editor that helps out).

If it's machine readable, logical operators should be prefix.  Syntax should
not be overly important.

If it's human writable, logical operators should be infix.  Syntax should be
geared towards preventing syntax errors and readability.

Any comments will be appreciated.

-- 
                                           Tim Showalter [email-masked]

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From: Randall Gellens <[email-masked]>
Date: Thu, 27 Mar 1997 14:41:46 -0800

> parens without an editor that helps out).

I think we should gear it towards human use.  That makes it easier to
debug, easier for people to create their own scripts without a user agent,
etc.  If we keep it simple enough, it will still be able to be read,
edited, and generated by a GUI user agent.

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From: Brian Moore <[email-masked]>
Date: Thu, 27 Mar 1997 18:09:10 -0800 (PST)

I believe machine readable is more important.

Let the user agent figure out a way to make it pretty: a filtering set
should be quickly parsed by a machine.  It's not too hard to make a gui
filter-maker that lets you cover various levels of user sophistication
(from full egrep parsing of headers and/or body to just 'has bob in the from
line').

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From: Amos A Gouaux <[email-masked]>
Date: Fri, 28 Mar 1997 09:02:29 -0600 (CST)

As I already mentioned to Tim, I personally think machine-readable is more
important.  Even if it were to be human-writable, from what I've seen
between Elm Filter and Procmail debates, folks are going to find it
difficult to write correct filtering rules unless the language is
simplistic to the point of being almost useless.  At my previous job, when
faculty wanted their mail filtered, we ended up writing the procmail
script ourselves (support staff).  So I would prefer to see this new
filtering language machine-readable and then have a tk or even java app as
the configuration tool.  Then eventually some kind of ACAP interface. 

Besides, with the movement towards client-server mail access with IMAP (or
POP), I think server-side filtering is going to be an increasingly
pressing issue.  It might even get to the point were editing local files
like one's ~/.forward is a less common occurrence.  And even if folks
still edited their own filter file, I would still prefer it to be
machine-readable so that the mail delivery mechanism would be as fast and
efficient as possible.

As for question of syntax, I'm certainly agreeable to it being LISP-like.
Hmmm, I wonder if I could then plug it into GNUS..  ;-)

amos

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From: Randall Gellens <[email-masked]>
Date: Fri, 28 Mar 1997 10:47:03 -0800

I've changed my mind -- I now agree that the syntax should be biased
towards machine-readability.  This will make it easier to implement (at
least on servers) and thus more widespread.