On 3/21/07, Edson Tirelli <tirelli@post.com> wrote:

   I think it is a dangerous move.
   It is easy for users to understand that each pattern matches a fact:

A( ... )
B( ... )
C( ... )

   If you start moving patterns to inside other patterns, you risk to
lose the legibility:

A( b == B( ... ), c == C(...) )

   Main problem I see is with cross product abuses:

A( oneb == B(...), thesameb == B(...) )

   The above may match the same B as intended, but may also match other
Bs, leading to errors and bugs that will be hard to track.
   I would continue making patterns explicit and not nested.

   Although, the object navigability is desired and much waited I think:

$b : B(...)
A( c == $b.c )

   Also, there are some cases that we would do good allowing nesting:

$c : Cheesery( ... )
$s : List( size < 3 ) from collect( Cheese( type == "stilton" ) from
$c.getCheeses() )

   Just my .02 c.

    []s
    Edson

Olenin, Vladimir (MOH) wrote:

>Don't have any antlr experience, but I'd say that would be a very valuable
>addition - probably more BAs would be able to pick it up this way (without
>having to fallback on custom DSL)
>
>Vlad
>
>-----Original Message-----
>From: rules-dev-bounces@lists.jboss.org
>[mailto:rules-dev-bounces@lists.jboss.org] On Behalf Of Mark Proctor
>Sent: 20 March 2007 15:54
>To: Rules Dev List
>Subject: Re: [rules-dev] sugar
>
>Could also allow:
>Cheese( name = Person( location == "london").favourCheese )
>
>Can also use this to constrain on the fact itself, instead of just a field:
>Person( cheese = Cheese( type == "stilton ) )
>
>This could be use in config options:
>Call( duration < CallConf().minDuration )
>
>But as Edson pointed out it is open to abuse and misunderstanding, how
>long till people do:
>Call( duration < CallConf().maxDuration, duration > CallConf().maxDuration )
>
>Which is more like doing the following which has cross product issues:
>CallConf( $maxDuration1 : maxDuration )
>CallConf( $maxDuration2 : maxDuration )
>Call( duration < ,$maxDuration1 duration > $maxDuration2 )
>
>Mark
>Mark Proctor wrote:
>
>
>>I've been thinking of an idea to make rules more expressive, its just
>>syntax sugar at the parser level, but thought i'd ask feedback - if
>>anyone with antlr skills wants to make this work, let us know :)
>>
>>Instead of doing:
>>$p : Person($favouriteCheese : favouriteCheese )
>>Cheese( name == $favouriteCheese )
>>
>>We should allow the following:
>>$p : Person()
>>Cheese( name == $p.favouriteCheese )
>>
>>We could take this further and in places where a pattern is not used
>>elsewhere allow:
>>Cheese( name == Person().favouriteCheese )
>>
>>Mark
>>
>>
>>
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>>
>>
>
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--
Edson Tirelli
Software Engineer - JBoss Rules Core Developer
Office: +55 11 3124-6000
Mobile: +55 11 9218-4151
JBoss, a division of Red Hat @ www.jboss.com

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