Legal in perl5:

 my $foo = foo( 1 );          # A
 my $foo = foo(1);            # B
 my $foo = foo (1);           # C
 my $foo = foo      (    1    # D
           );

##</code><code>##

my $foo = $object->method (1)
                 ->method (2)
                 ->method (3);

##</code><code>##

my $foo = $object.method(1)
                 .method(2)
                 .method(3);

##</code><code>##

$ cat t.pl
use v6;

class C {
   has Int $.x is rw = 0;

   method foo (Int $i) { $!x += $i; return self; }
   method bar (Int $i) { $!x -= $i; return self; }
   }

C.new().foo(1).bar(2).say;
$ perl6 t.pl
C.new(x => -1)
$ cat t.pluse v6;

class C {
   has Int $.x is rw = 0;

   method foo (Int $i) { $!x += $i; return self; }
   method bar (Int $i) { $!x -= $i; return self; }
   }

C.new()
 .foo(1)
 .bar(2)
 .say;
$ perl6 t.pl
===SORRY!=== Error while compiling t.pl
Two terms in a row
at t.pl:11
------>  &#9167;.foo(1)
    expecting any of:
        infix stopper
        infix or meta-infix
        statement end
        statement modifier
        statement modifier loop

##</code><code>##

cat t.pl
use v6;

class C {
   has Int $.x is rw = 0;

   method foo (Int $i) { $!x += $i; return self; }
   method bar (Int $i) { $!x -= $i; return self; }
   }

C.new()\
 .foo(1)\
 .bar(2)\
 .say;
$ perl6 t.pl
C.new(x => -1)