[rules-dev] Drools syntax diagrams - redrawn

[Mark Proctor]

  yes, ? wasn't easy due to java and data munging would get messy as we 
map between things.

So we just left it as any valid java identifier, but using the $ prefix 
as a coding convention make it easier to differentiate fieldnames and 
bindings
Person( age : age )
Person( age == age )

The above looks a little confusing compared to:
Person( $age : age )
Person( age == $age )

Davide wants to enforce the $ prefix so that parsing can be easier.

Mark
On 24/09/2010 00:31, Michael Neale wrote:
> The $name: Pattern thing I am convinced is to do with Mark's prior 
> history of being abused by perl ;)
>
> But the real reason is we wanted to use ?name: Pattern() - using "?" 
> like the clips lineage of languages - but IIRC even ilog allows that. 
> We wanted our labels to be compatible with java source code - where 
> $variable is a valid name (although no one actually uses it) and ?name 
> is not.
>
> So here we are ;)
>
>
> On Fri, Sep 24, 2010 at 12:29 AM, Greg Barton <greg_barton at yahoo.com 
> <mailto:greg_barton at yahoo.com>> wrote:
>
>     Yes, and I don't think we want to take readability cues from Perl. :)
>
>     GreG
>
>     On Sep 23, 2010, at 3:03, Wolfgang Laun <wolfgang.laun at gmail.com
>     <mailto:wolfgang.laun at gmail.com>> wrote:
>
>>     On 23 September 2010 09:31, Bruno Unna <bruno.unna at gmail.com
>>     <mailto:bruno.unna at gmail.com>> wrote:
>>
>>         FWIW: in Perl, there are both operators as well (|| and
>>         'or'). However, they are *not* exactly the same. Although
>>         they can be used in any context to render a boolean
>>         expression, their priority makes the difference. Taken from
>>         official documentation (http://bit.ly/dgw4GT):
>>
>>
>>     Low precedence "and", "or", "xor" were introduced to permit "Perl
>>     poetry", or, more seriously, to
>>     permit control flow using a logical expression, especially after
>>     function calls without parentheses.
>>        see Naples or die;  # same as: see(Napes) || die(); but not:
>>     see(Naples || die() );
>>
>>     No way this makes any sense in Drools.
>>
>>     -W
>>
>>>         Binary "or" returns the logical disjunction of the two
>>>         surrounding expressions. It's equivalent to || except for
>>>         the very low precedence. This makes it useful for control flow.
>>
>>         Nonetheless, it must be taken into account that the
>>         distinction makes sense for a Perl programmer. For a
>>         rules-writing guy (or girl) perhaps the distinction is
>>         extremely obscure.
>>
>>         Regards.
>>
>>
>>
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>
>
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>
>
>
> -- 
> Michael D Neale
> home: www.michaelneale.net <http://www.michaelneale.net>
> blog: michaelneale.blogspot.com <http://michaelneale.blogspot.com>
>
>
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