Junctions seem way more complex than that, first there are 4 different junction contains (any, all, one and none), second they overload 12 comparison operators each and third the other operand doesn't have to be a junction.
So e.g. any(@ar1) == any(@ar2) is an intersection but any(@ar1) == $val is a containment, and I've no idea what all(@ar1) < any(@ar2) would be, I guess it would check that max(ar1) < max(ar2)?
It seems that it just expands the lists using the operator. The output from junctions is quite nice:
> my @a = <1 2 3 4>;
> my @b = <2 3>;
> say all(@a) < any(@b);
all(any(True, True), any(False, True), any(False, False), any(False, False))
> say so all(@a) < any(@b);
False junction1 = val1 | val2 | val3;
junction2 = val4 & val5;
if junction1 op junction2 { ... };
* Makes $x == 5|6 look kinda cool
* $string ~~ /<first>/ & /<second>/ & /<third>/ # matches all three regexes. huh. kinda cool
* (5|6).foo maybe we can do that in cpu-parallel (it doesn't now)? That might be kinda cool
* sub is-prime($n where $n > 2) { $n % none(2..sqrt($n)) == 0 } # Logical O(1) prime test if only you had that quantum-coprocessor? That... would be kinda cool
* ... you might notice a pattern to the motivation for this feature :)
no idea what all(@ar1) < any(@ar2) would be
> my @a = <1 2 3 4>;
[1 2 3 4]
> my @b = <2 3>;
[2 3]
> say so all(@a) < any(@b);
False
> say so all(@b) < any(@a);
True