[v6] More fixes; harness can do "Hello, world" now

v6/Begin.pm6

@@ -7,6 +7,7 @@ use Unit;
 use Sig;
 use Body;
 use Op;
+use Metamodel;
 
 ### Code goes here to build up the metamodel from an Op tree
 # We should eventually wire this to the parser, so that metamodel stuff can

v6/Metamodel.pm6

@@ -67,7 +67,7 @@ class Namespace {
             }
 
             $cursor{$k} //= ['var',Any,Any];
-            if !$cursor{$k}[2] {
+            if !defined $cursor{$k}[2] {
                 $.log.push(['pkg',[@$used, $k]]);
                 $cursor{$k}[2] = {};
             }
@@ -560,7 +560,7 @@ class StaticSub is RefTarget {
         $.lexicals{$slot} = Metamodel::Lexical::SubDef.new(:$body);
     }
 
-    method add_pkg_export($unit, $name, $path2, $tags) {
+    method add_pkg_exports($unit, $name, $path2, $tags) {
         for @$tags -> $tag {
             $unit.bind_graft([@$.cur_pkg, 'EXPORT', $tag, $name], $path2);
         }

v6/harness

@@ -4,14 +4,31 @@ use Body;
 use Unit;
 use Begin;
 use JSYNC;
+use NAMOutput;
 
 my $ast = Unit.new(
-    name => "MAIN",
+    name => "CORE",
     mainline => Body.new(
-        do => ::Op::CgOp.new(optree => ['prog', ['say', ['str', 'Hello, world']], ['null', 'var']]),
+        do => ::Op::StatementList.new(children => [
+            ::Op::ClassDef.new(name => 'Mu', var => 'Mu', bodyvar => '!0',
+                body => Body.new(do => ::Op::StatementList.new(children => [
+                ]))),
+            ::Op::ClassDef.new(name => 'Any', var => 'Any', bodyvar => '!1',
+                body => Body.new(do => ::Op::StatementList.new(children => [
+                    ::Op::Super.new(name => 'Mu'),
+                ]))),
+            ::Op::ClassDef.new(name => 'Nil', var => 'Nil', bodyvar => '!2',
+                body => Body.new(do => ::Op::StatementList.new(children => [
+                ]))),
+            ::Op::ClassDef.new(name => 'ClassHOW', var => 'ClassHOW', bodyvar => '!3',
+                body => Body.new(do => ::Op::StatementList.new(children => [
+                ]))),
+            ::Op::CgOp.new(optree => ['prog', ['say', ['str', 'Hello, world']], ['null', 'var']]),
+        ]),
         returnable => False));
 
 my %*units;
 my $mm = $ast.begin;
+my $nstr = NAMOutput.run($mm);
 
-say to-jsync($mm);
+say $nstr;