use v6-alpha;

use Test;

plan 16;

# L<S04/"The Relationship of Blocks and Declarations" /There is a new state declarator that introduces/>

# state() inside subs
{
    sub inc () {
        state $svar;
        $svar++;
        return $svar;
    };

    is(inc(), 1, "state() works inside subs (#1)");
    is(inc(), 2, "state() works inside subs (#2)");
    is(inc(), 3, "state() works inside subs (#3)");
}

# state() inside coderefs
{
    my $gen = {
        # Note: The following line is only executed once, because it's equivalent
        # to
        #   state $svar will first { 42 };
        # See L<S04/"Closure traits" /emantics to any initializer, so this also works/>
        state $svar = 42;
        my $ret = { $svar++ };
    };

    my $a = $gen(); # $svar == 42
    $a(); $a();     # $svar == 44
    my $b = $gen(); # $svar == 44

    is $b(), 44, "state() works inside coderefs";
}

# state() inside for-loops
{
    for 1,2,3 -> $val {
        state $svar;
        $svar++;

        # Only check on last run
        if $val == 3 {
            is $svar, 3, "state() works inside for-loops";
        }
    }
}

# state will first {...}
{
    my ($a, $b);
    eval '
        my $gen = {
            state $svar will first { 42 };
            -> { $svar++ };
        }
        $a = $gen();    # $svar == 42
        $a(); $a();     # $svar == 44
        $b = $gen()();  # $svar == 44
    ';

    is $b, 44, 'state will first {...} works', :todo<feature>;
}

# Return of a reference to a state() var
{
    my $gen = {
        state $svar = 42;
        \$svar;
    };

    my $svar_ref = $gen();
    $$svar_ref++; $$svar_ref++;

    my $svar_ref = $gen();
    is $$svar_ref, 44, "reference to a state() var", :todo<bug>;
}

# Anonymous state vars
# L<"http://groups.google.de/group/perl.perl6.language/msg/07aefb88f5fc8429">
{
    # XXX -- currently this is parsed as \&state()
    my $gen = eval '{ try { \state } }';
    $gen //= sub { my $x; \$x };

    my $svar_ref = $gen();               # $svar == 0
    try { $$svar_ref++; $$svar_ref++ };  # $svar == 2

    my $svar_ref = $gen();               # $svar == 2
    is try { $$svar_ref }, 2, "anonymous state() vars", :todo<feature>;
}

# L<"http://www.nntp.perl.org/group/perl.perl6.language/20888">
# ("Re: Declaration and definition of state() vars" from Larry)
{
    my ($a, $b);
    eval '
        my $gen = {
            (state $svar) = 42;
            my $ret = { $svar++ };
        };

        $a = $gen();        # $svar == 42
        $a(); $a();         # $svar == 44
        $b = $gen()();      # $svar == 42
    ';
    is $b, 42, "state() and parens"; # svar == 43
}

# state() inside regular expressions
{
    my $str = "abc";

    my $re  = {
    # Perl 5 RE, as we don't want to force people to install Parrot ATM. (The
    # test passes when using the Perl 6 RE, too.)
    $str ~~ s:Perl5/^(.)/{
      state $svar;
      ++$svar;
    }/;
    };
    $re();
    $re();
    $re();
    is +$str, 3, "state() inside regular expressions works";
}

# state() inside subs, chained declaration
{
    sub step () {
        state $svar = state $svar2 = 42;
        try {
            $svar++;
            $svar2--;
            return ($svar, $svar2);
        }
    };

    is(step().perl, "(43, 41)", "chained state (#1)", :todo<bug>);
    is(step().perl, "(44, 40)", "chained state (#2)", :todo<bug>);
}

# state in cloned closures
{
    for <first second> {
        my $code = {
            state $foo = 42;
            ++$foo;
        };

        is $code(), 43, "state was initialized properly ($_ time)";
        is $code(), 44, "state keeps its value across calls ($_ time)";
    }
}