[news.eclipse.modeling.gmt] [Epsilon] Problem with ECL

[ste_barr@xxxxxxxxxxxxxxx (Steve Barrett)]

Hello,

I'm trying to use ECL to help with some model merging. Unfortunately I'm 
stuck.

My left model consits of a single class A, and the right a single class B. 
I'm using the follow code (class.ecl) to compare them and print out the 
match trace:


rule ClassA
 match l : Left!Class with r : Right!Class {
 compare : l.name = 'A' }

rule ClassB
 match l : Left!Class with r : Right!Class {
 compare : l.name = 'B' }

post {
 -- Print name of matching elements and of the rule that matched them.
 for (m in matchTrace.matches.select(m|m.isMatching)) {
   (m.left.name + ' <' + m.getRule().name + '> ' + 
m.right.name).println();
 }
}


I think that the four element pairings should cause each rule to fire 
once, so the output is a surprise to me:


A <ClassA> A
A <ClassA> B


Where are the B to A, B to B pairings? Why did rule ClassA match A with B? 
And why does the second rule never fire?

I can't help put think that I'm missing something really basic here, but I 
have spent a bit of time trying to unravel this. Thanks for taking a look.

--Steve

P.S. I couldn't get "m.rules.first().name" as given in the Complete OO to 
DB comparison to work, which is why I'm using "m.getRule().name" Could 
this be a source of trouble?