Implement while and until loops

Niecza/Actions.pm

@@ -888,6 +888,18 @@ sub statement_control__S_if { my ($cl, $M) = @_;
         false => $else);
 }
 
+sub statement_control__S_while { my ($cl, $M) = @_;
+    $M->{_ast} = Op::WhileLoop->new(check => $M->{xblock}{_ast}[0],
+        body => $cl->block_to_immediate($M->{xblock}{_ast}[1]),
+        until => 0, once => 0);
+}
+
+sub statement_control__S_until { my ($cl, $M) = @_;
+    $M->{_ast} = Op::WhileLoop->new(check => $M->{xblock}{_ast}[0],
+        body => $cl->block_to_immediate($M->{xblock}{_ast}[1]),
+        until => 1, once => 0);
+}
+
 sub package_def { my ($cl, $M) = @_;
     if ($::PKGDECL ne 'class') {
         $M->sorry('Non-class package definitions are not yet supported');

Op.pm

@@ -177,6 +177,43 @@ use 5.010;
     no Moose;
 }
 
+{
+    package Op::WhileLoop;
+    use Moose;
+    extends 'Op';
+
+    has check => (isa => 'Op', is => 'ro', required => 1);
+    has body  => (isa => 'Op', is => 'ro', required => 1);
+    has once  => (isa => 'Bool', is => 'ro', required => 1);
+    has until => (isa => 'Bool', is => 'ro', required => 1);
+
+    sub void_cg {
+        my ($self, $cg, $body) = @_;
+
+        my $l1 = $cg->label;
+        my $l2 = $self->once ? 0 : $cg->label;
+
+        $cg->goto($l2) unless $self->once;
+        $cg->labelhere($l1);
+        $self->body->void_cg($cg, $body);
+        $cg->labelhere($l2) unless $self->once;
+        $self->check->item_cg($cg, $body);
+        $cg->fetch;
+        $cg->unbox('Boolean');
+        my $m = $self->until ? 'ncgoto' : 'cgoto';
+        $cg->$m($l1);
+    }
+
+    sub item_cg {
+        my ($self, $cg, $body) = @_;
+        $self->void_cg($cg, $body);
+        $cg->push_null('Variable');
+    }
+
+    __PACKAGE__->meta->make_immutable;
+    no Moose;
+}
+
 {
     package Op::Num;
     use Moose;