use v6-alpha;

use Test;

# XXX: 20 tests should be run, but because of the various eval()s dieing too
# early, currently there're only 10 tests run.
# So, to avoid "7/20 failed" messages, *temporarily* pretend that only 13 tests
# are planned.
plan 13;

=pod

Tests subtypes, specifically in the context of multimethod dispatch.

L<S12/"Types and Subtypes">

=cut

my $abs = '
multi sub my_abs (Num where { $^n >= 0 } $n){ $n }
multi sub my_abs (Num where { $^n <  0 } $n){ -$n }
';

ok(eval("$abs; 1"), "we can compile subtype declarations", :todo<feature>);

is(eval("$abs; my_abs(3)"), 3, "and we can use them, too", :todo<feature>);
is(eval("$abs; my_abs(-5)"), 5, "and they actually work", :todo<feature>);


# Basic subtype creation
ok eval('subtype Num::Odd of Num where { $^num % 2 == 1 }'),
  "subtype is correctly parsed", :todo<feature>;
is eval('my Num::Odd $a = 3'), 3, "3 is an odd num";
# The eval inside the eval is/will be necessary to hider our smarty
# compiler's compile-time from bailing.
# (Actually, if the compiler is *really* smarty, it will notice our eval trick,
# too :))
is eval('my Num::Odd $b = 3; try { $a = eval 4 }; $a'), 3,
  "objects of Num::Odd don't get even", :todo<feature>;

# The same, but lexically
my $eval1 = '{
  my subtype Num::Even of Num where { $^num % 2 == 0 }
  ok my Num::Even $c = 6, :todo<feature>;
  ok $c ~~ Num::Even, "our var is a Num::Even", :todo<feature>;
  try { $c = eval 7 }
  is $c, 6, "setting a Num::Even to an odd value dies", :todo<feature>;
}';
eval $eval1;
ok eval('!try { my Num::Even $d }'),
  "lexically declared subtype went out of scope";

# Subs with arguments of a subtype
ok eval('sub only_accepts_odds(Num::Odd $odd) { $odd + 1 }'),
  "sub requiring a Num::Odd as argument defined (1)", :todo<feature>;
is eval('only_accepts_odds(3)'), 4,
  "calling sub worked";
ok eval('!try { only_accepts_odds(4) }'),
  "calling sub did not work", :todo<feature>;

# Normal Ints automatically morphed to Num::Odd
ok eval('sub is_num_odd(Num::Odd $odd) { $odd ~~ Num::Odd }'),
  "sub requiring a Num::Odd as argument defined (2)", :todo<feature>;
ok eval('is_num_odd(3)'), "Int automatically morphed to Num::Odd", :todo<feature>;
is eval('only_accepts_odds("3")'), 4, "Str automatically morphed to Num::Odd";

# Following code is evil, but should work:
my $eval2 = '
  my Int $multiple_of;
  subtype Num::Multiple of Num where { $^num % $multiple_of == 0 }

  $multiple_of = 5;
  ok $multiple_of ~~ Isa, "basic sanity (1)", :todo<feature>;
  is $multiple_of,     5, "basic sanity (2)", :todo<feature>;

  ok my Num::Multiple $d = 10, "creating a new Num::Multiple", :todo<feature>;
  is $d,                   10, "creating a new Num::Multiple actually worked", :todo<feature>;
  
  $multiple_of = 6;
  ok !try { my Num::Multiple $e = eval 10 },
    "changed subtype definition worked";
';
eval $eval2;