Dump .fallback for VarWithFallback when doing --target=ast.

Generalize printing out of tagged children nodes.

Author: pmurias

src/QAST/Children.nqp

@@ -31,7 +31,27 @@ role QAST::Children {
         }
     }
 
+    method extra_children() {
+        [];
+    }
+
     method dump_children(int $indent, @onto) {
-        self.dump_node_list($indent, @onto, @!children);
+        my $extra := 0;
+        for self.extra_children -> $tag, $nodes {
+            if $nodes {
+                nqp::push(@onto, nqp::x(' ', $indent));
+                nqp::push(@onto, "[" ~ $tag ~ "]");
+                nqp::push(@onto, "\n");
+                self.dump_node_list($indent+2, @onto, $nodes);
+            }
+            $extra := $extra + nqp::elems($nodes);
+        }
+
+        if $extra && @!children {
+            nqp::push(@onto, nqp::x(' ', $indent) ~ "[children]\n");
+            self.dump_node_list($indent+2, @onto, @!children);
+        } else {
+            self.dump_node_list($indent, @onto, @!children);
+        }
     }
 }

src/QAST/CompUnit.nqp

@@ -59,20 +59,10 @@ class QAST::CompUnit is QAST::Node does QAST::Children {
         $!code_ref_blocks := $value unless $value =:= NO_VALUE; $!code_ref_blocks
     }
 
-    method dump_children(int $indent, @onto) {
-        if self.pre_deserialize {
-            nqp::push(@onto, nqp::x(' ', $indent) ~ "[pre deserialize]\n");
-            self.dump_node_list($indent, @onto, self.pre_deserialize);
-        }
-
-        if self.post_deserialize {
-            nqp::push(@onto, nqp::x(' ', $indent) ~ "[post deserialize]\n");
-            self.dump_node_list($indent, @onto, self.post_deserialize);
-        }
-
-        if self.pre_deserialize || self.post_deserialize {
-            nqp::push(@onto, nqp::x(' ', $indent) ~ "[children]\n") 
-        }
-        self.dump_node_list($indent, @onto, self.list);
+    method extra_children() {
+        [
+            'pre_deserialize', self.pre_deserialize,
+            'post_deserialize', self.post_deserialize
+        ];
     }
 }

src/QAST/VarWithFallback.nqp

@@ -1,4 +1,8 @@
 class QAST::VarWithFallback is QAST::Var {
     has $!fallback;
     method fallback($value = NO_VALUE) { $!fallback := $value unless $value =:= NO_VALUE; $!fallback }
+
+    method extra_children() {
+        $!fallback ?? ['fallback', [$!fallback]] !! [];
+    }
 }