From donaldp@apache.org  Sat Jan  6 03:33:49 2001
Return-Path: <donaldp@apache.org>
Mailing-List: contact ant-dev-help@jakarta.apache.org; run by ezmlm
Delivered-To: mailing list ant-dev@jakarta.apache.org
Received: (qmail 48221 invoked from network); 6 Jan 2001 03:33:49 -0000
Received: from mail.alphalink.com.au (203.24.205.7)
  by h31.sny.collab.net with SMTP; 6 Jan 2001 03:33:49 -0000
Received: from donalgar (d102-ps3-mel.alphalink.com.au [202.161.108.230])
	by mail.alphalink.com.au (8.9.3/8.9.3) with SMTP id OAA12279;
	Sat, 6 Jan 2001 14:33:58 +1100
Message-Id: <3.0.6.32.20010106143045.00a12850@latcs2.cs.latrobe.edu.au>
X-Sender: pjdonald@latcs2.cs.latrobe.edu.au
X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.6 (32)
Date: Sat, 06 Jan 2001 14:30:45 +1100
To: ant-dev@jakarta.apache.org
From: Peter Donald <donaldp@apache.org>
Subject: Re: [PROPOSAL] Enhancement to available task
Cc: <ant-dev@jakarta.apache.org>
In-Reply-To: <006101c0774e$551d1e60$cd85edc1@oxspring>
References: <3.0.6.32.20010103131032.0089aab0@latcs2.cs.latrobe.edu.au>
 <3.0.6.32.20010105125420.00a1c690@latcs2.cs.latrobe.edu.au>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
X-Spam-Rating: h31.sny.collab.net 1.6.2 0/1000/N

At 07:32  5/1/01 -0000, Rob Oxspring wrote:
>I may be being daft, but I can't see how this could easily build up "or"s -
>assuming that these things are "and"ed together -
>however if the available task also took a "operation" attribute, the task
>could combine the conditions appropriately... Example steeling from Ceki
>Gulcu's "Conditional compilation" request:
>
><available property="case1" operation="and">
>    <if ...test for JNDI... />
>    <if ...test for JMS... />
></available>
>
><available property="case2" operation="or">
>    <if ...test for JAXP from Sun... />
>    <if ...test for Xerces... />
></available>

Sorry I am ex-philosophy major so I guess I forgot to explain how it
happens ;) Namely like 

<available property="case1">
    <unless ...test for A... />
    <unless ...test for B... />
</available>

<available property="case2">
    <unless property="case1" />
</available>

ie the equivelent of
~(~A & ~B) == A v B
or
!(!A && !B) == A || B


Cheers,

Pete

*-----------------------------------------------------*
| "Faced with the choice between changing one's mind, |
| and proving that there is no need to do so - almost |
| everyone gets busy on the proof."                   |
|              - John Kenneth Galbraith               |
*-----------------------------------------------------*