Actually `=` sort-of only does one thing. It asks the left argument what it wants to do with the values.

    my @a = 1,2,3;

is almost the same as

    my @a;
    @a.VAR.STORE((1,2,3));

---

As for separate positional and associative access:

Raku has separate positional and named arguments to functions.

An argument list is actually a singular thing called a Capture. Even if it usually pretends to not be.

    my \capture = \( 'a', b => 10 ); # Capture litteral

    say capture[0];   # a
    say capture{'b'}; # 10


    sub foo ( |capture ) {
      say capture[0];   # a
      say capture{'b'}; # 10
    }

    foo |capture; # give it the above capture litteral
    # foo 'a', b => 10

    sub bar ( $a, :$b ){
      say $a; # a  (positional)
      say $b; # 10 (named)
    }

    bar |capture; # give it the above capture litteral
    # bar 'a', b => 10

To be able to easily extract out those parts, it helps if there is a different way to get at each.

The same thing also applies to extracting information out of regexes

    'a10' ~~ / (.) # $0
       $<b> = (..) # $<b>
    /;

    say $0;   # a
    say $<b>; # 10

    say $/[0];   # a  (positional index into $/)
    say $/{'b'}; # 10 (named index into $/)