[rules-users] forall not delivering as expected

[Wolfgang Laun]

Since the following rule is just a variant of (Expert) Example 4.66, "All
Buses are Red", I think that there is a bug, in 5.1.1:

// Does not fire even though all Triangle have all sides > 0
rule "All triangle sides are greater than 0"
when
    forall( Triangle( a > 0, b > 0, c > 0 ) )
then
    System.out.println( "All triangle sides are > 0." );
end

Also, the tortuous equivalent does not fire:

// Does not fire even though all Triangle have all sides > 0
rule "All triangle sides are greater than 0"
when
    forall( $t: Triangle()
               Triangle( this == $t, a > 0, b > 0, c > 0 ) )
then
    System.out.println( "All triangle sides are > 0." );
end

-W


On 12 September 2010 19:45, Wolfgang Laun <wolfgang.laun at gmail.com> wrote:

> Given classes
>    class Triangle { int a, b, c;... }
>    class Quadrangle { int a, b, c, d;... }
> with appropriate getters (but no hashCode or equals) and these facts
>    Triangle( 3, 3, 3 )
>    Triangle( 3, 3, 3 )  // a duplicate, intentional
>    Quadrangle ( 3, 4, 5, 6 );
> the rule
>    rule "all equilaterals have a 'fitting' quadrangle"
>    when
>       forall( Triangle( $a: a, b == $a, c == $a )
>          Quadrangle( a == $a || b == $a || c == $a || d == $a ) )
>    then // ...
>    end
> works as expected - it fires.
>
> But the rule
>    rule "all equilaterals have a duplicate"
>    when
>       forall( $t: Triangle( $a: a, b == $a, c == $a )
>          Triangle( this != $t, a == $a, b == $a , c == $a ) )
>    then // ...
>    end
> does not fire, not even when I omit this != $t. Why?
>
> Do I have a white spot in my grey cells? Please tint my taint...
>
> -W
>
>
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