> my Int $a
> $a = 3
3
> $a = "a"
Type check failed in assignment to $a; expected Int but got Str
  in block <unit> at <unknown file>:1

> CORE.HOW
Perl6::Metamodel::ModuleHOW.new
> $a = CORE
> $a.HOW
Perl6::Metamodel::ModuleHOW.new
> Iterable.gist
Method 'iterator' must be implemented by Iterable because it is required by a role
> 
> 
> CORE::.keys.grep(/d$/).sort.elems
24
> CORE::.keys.grep(/d$/).sort.map({ CORE::{$_} }).elems
17
> CORE::.keys.grep(/d$/).sort
($=pod &append &chmod &dd &defined &end &expmod &ord &prepend &proceed &rand &repeated &round &srand &succeed FileChanged FileRenamed IterationEnd Method Planned Pod SeekFromEnd Submethod Thread)
> 
[1]+  Stopped                 rlwrap ./rakudo_inst/bin/perl6
$ cat IterationEnd_note
Note: The only valid use of the sentinel value C<IterationEnd> in a program
is identity comparison (using C<=:=>) with the result of a method in the
iterator API. Any other behavior is undefined and implementation dependent.
$ fg
rlwrap ./rakudo_inst/bin/perl6
> 
> 
> my @a = (1,2,3)
[1 2 3]
> @a[1] = slip(4,5)
(4 5)
> @a
[1 (4 5) 3]
> @a.map({ $_ })
(1 4 5 3)
> @a.map({ slip($_) })
(1 4 5 3)
> @a.map({ my @s = $_; @s.Slip })
(1 (4 5) 3)
> 
> 
> 3.HOW
Perl6::Metamodel::ClassHOW.new
> 3.WHICH
Int|3
> 3."WHICH"()
Int|3
> 3."HOW"()
Method 'HOW' not found for invocant of class 'Int'
> 3.^isa(Int)
1
> 
> 
> (1,2,3)[0] := 4

$