undefined-types.t

useTest;
plan49;

# L<S02/Names and Variables/The empty>

# Empty is an empty container. As a container, it is defined.
{
ok ().defined, '() is defined';
my@a=1, Nil, 3;
is@a.elems, 3, 'Nil as part of list is element';
@a=1, Empty, 3;
is@a.elems, 2, 'Empty as part of list, is empty list';
ok (@a.push: Empty) =:=@a, "Pushing Empty returns same array";
is@a.elems, 2, 'Pushing Empty in list context is empty list';
ok (@a.unshift: Empty) =:=@a, "Unshifting Empty returns same array";
is@a.elems, 2, 'Unshifting Empty in list context is empty list';
is (@a= Empty), '', "Setting array to Empty returns empty string";
is@a.elems, 0, 'Setting to Empty restores original state';
} #7

# typed scalar
{
myInt$a=1;
is ($a=Nil), Int, "assigning Nil to Int should work";
ok!$a.defined, "Nil makes undefined here";
} #2

# typed array
{
myInt@a=1, Empty, 3;
#?rakudo todo ".clone doesn't copy typedness"
is@a.of, '(Int)', "Check that we have an 'Int' array";
is@a.elems, 2, 'Empty as part of Int list, is empty list';
ok ( @a.push: Empty ) =:=@a, "assigning Empty returns same array";
is@a.elems, 2, 'Pushing Empty in Int list context is empty list';
ok ( @a.unshift: Empty ) =:=@a, "assigning Empty returns same array";
is@a.elems, 2, 'Unshifting Empty in Int list context is empty list';
ok!defined(@a[1] =Nil), "assigning Nil to Int should work";
ok!@a[1].defined, "Nil makes undefined here";
is (@a= Empty), '', "setting array to Empty returns empty string";
#?rakudo todo ".clone doesn't copy typedness"
is@a.of, '(Int)', "Check that we still have an 'Int' array";
is@a.elems, 0, 'Setting to Empty restores original state';
} #11

# typed hash
{
myInt%a=a =>1, Empty, c =>3;
#?rakudo todo ".clone doesn't copy typedness"
is%a.of, '(Int)', "Check that we have an 'Int' hash";
is%a.elems, 2, 'Empty as part of Int list, is empty pair';
is (%a<b> =Nil), Int, "assigning Nil to hash element should work";
ok!%a<b>.defined, "Nil makes undefined here";
is ( %a= Empty ), '', "setting hash to Empty returns empty string";
#?rakudo todo ".clone doesn't copy typedness"
is%a.of, '(Int)', "Check that we still have an 'Int' hash";
is%a.elems, 0, 'Setting to Empty restores original state';
} #7

# sink context returns Nil
{
my@a;
my$i=0;
@a.push:1, sink $i++;
is@a.elems, 2, 'sink statement prefix returns Nil (list context)';
is$i, 1, 'sink execucted the statement';

@a= ();
@a.push:2, sink { $i=2 };
is@a.elems, 2, 'sink block prefix returns Nil (list context)';
is$i, 2, 'the block was executed';
ok!defined(sink $i=5 ), 'sink in scalar context (statement)';
is$i, 5, '... statement executed';
ok!defined(sink {$i=8} ), 'sink in scalar context (block)';
is$i, 8, '... block executed';
} #8

# undefined objects
{
my$obj;
myInt$int;

is~$obj, '', 'prefix:<~> on type object gives empty string (Any)';
is~$int, '', 'prefix:<~> on type object gives empty string (Int)';
is$obj.Stringy, '', '.Stringy on type object gives empty string (Any)';
is$int.Stringy, '', '.Stringy on type object gives empty string (Int)';

ok (~$obj) ~~Stringy, 'prefix:<~> returns a Stringy (Any)';
ok (~$int) ~~Stringy, 'prefix:<~> returns a Stringy (Int)';

ok$obj.Stringy~~Stringy, '.Stringy returns a Stringy (Any)';
ok$int.Stringy~~Stringy, '.Stringy returns a Stringy (Int)';

is$obj.gist, '(Any)', '.gist on type object gives (Any)';
is$int.gist, '(Int)', '.gist on type object gives (Int)';

is'a'~$obj, 'a', 'infix:<~> uses coercion to Stringy (Any)';
is'a'~$int, 'a', 'infix:<~> uses coercion to Stringy (Int)';
} #12

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