Sketch out simple Volatile/DirTree module

Author: japhb

META6.json

@@ -58,6 +58,7 @@
     "Terminal::Widgets::Utils::Color": "lib/Terminal/Widgets/Utils/Color.rakumod",
     "Terminal::Widgets::Viewer::Log": "lib/Terminal/Widgets/Viewer/Log.rakumod",
     "Terminal::Widgets::Viz::SmokeChart": "lib/Terminal/Widgets/Viz/SmokeChart.rakumod",
+    "Terminal::Widgets::Volatile::DirTree": "lib/Terminal/Widgets/Volatile/DirTree.rakumod",
     "Terminal::Widgets::Widget": "lib/Terminal/Widgets/Widget.rakumod"
   },
   "resources": [

lib/Terminal/Widgets/Volatile/DirTree.rakumod

@@ -0,0 +1,51 @@
+# ABSTRACT: A volatile data structure representing a live directory tree
+
+unit module Terminal::Widgets::Volatile::DirTree;
+
+
+role Node {
+    has IO::Path:D() $.path is required;
+    has Node         $.parent;
+
+    method gist() {
+        my $short-name = self.^name.subst('Terminal::Widgets::Volatile::', '');
+        $short-name ~ ':' ~ $!path.path
+    }
+}
+
+class Dev does Node {
+}
+
+class File does Node {
+}
+
+class SymLink does Node {
+    has IO::Path:D() $.target is required;
+
+    method gist() {
+        self.Node::gist ~ ' => ' ~ $!target.path
+    }
+}
+
+class Dir does Node {
+    has Node:D    @!children   is built;
+    has Instant:D $.cache-time .= from-posix-nanos(0);
+
+    method children(Bool:D :$refresh = False) {
+        # XXXX: For now, just fake real caching and be lazy
+        if $refresh || !$!cache-time {
+            $!cache-time = now;
+            @!children   = $!path.dir.map: {
+                .d   ?? Dir.new(    parent => self, path => $_) !!
+                .l   ?? SymLink.new(parent => self, path => $_, target => .readlink) !!
+                .f   ?? File.new(   parent => self, path => $_) !!
+                .dev ?? Dev.new(    parent => self, path => $_) !!
+                        Node.new(   parent => self, path => $_) ;
+            };
+        }
+        @!children
+    }
+}
+
+class Root is Dir {
+}