Re: [rules-dev] Drools syntax diagrams - redrawn

Java allows confusing constructs too but they are left for the developer to handle rather than imposed by the language specification:- class Smurf { int a; int b; Smurf(int a, int b) { a = a; b = b; } } ________________________________ From: rules-dev-bounces(a)lists.jboss.org [mailto:rules-dev-bounces@lists.jboss.org] On Behalf Of Mark Proctor Sent: 24 September 2010 00:46 To: rules-dev(a)lists.jboss.org Subject: Re: [rules-dev] Drools syntax diagrams - redrawn 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(a)yahoo.com&gt; 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(a)gmail.com&gt; wrote: On 23 September 2010 09:31, Bruno Unna <bruno.unna(a)gmail.com&gt; 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. _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev -- Michael D Neale home: www.michaelneale.net blog: michaelneale.blogspot.com _______________________________________________ rules-dev mailing list rules-dev(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-dev