Factor Volatile::Tree out of Volatile::DirTree

Author: japhb

META6.json

@@ -59,6 +59,7 @@
     "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::Volatile::Tree": "lib/Terminal/Widgets/Volatile/Tree.rakumod",
     "Terminal::Widgets::Widget": "lib/Terminal/Widgets/Widget.rakumod"
   },
   "resources": [

lib/Terminal/Widgets/Volatile/DirTree.rakumod

@@ -2,31 +2,27 @@
 
 unit module Terminal::Widgets::Volatile::DirTree;
 
+use Terminal::Widgets::Volatile::Tree;
 
-role Node {
-    has IO::Path:D() $.path is required;
-    has Node         $.parent;
+constant Tree = Terminal::Widgets::Volatile::Tree;
 
 
-    #| Simplified gist that does not traverse parents
-    method gist(::?CLASS:D:) {
-        my $short-name = self.^name.subst('Terminal::Widgets::Volatile::', '');
-        $short-name ~ ':' ~ $!path.path
-    }
+role PathContainer {
+    has IO::Path:D() $.path is required;
 
-    #| Find root node via parent chain, runtime is O(depth)
-    method root(::?CLASS:D:) {
-        my $root = self;
-        $root .= parent while $root.parent;
-        $root
+    #| Simplified gist that does not traverse parents, and includes path
+    method gist(::?CLASS:D:) {
+        self.gist-name ~ ':' ~ $!path.path
     }
 }
 
-class Dev does Node {
-}
+role Node   does Tree::Node   does PathContainer { }
+role Leaf   does Tree::Leaf   does PathContainer { }
+role Parent does Tree::Parent does PathContainer { }
 
-class File does Node {
-}
+class Misc does Node { }
+class File does Leaf { }
+class Dev  does Node { }
 
 class SymLink does Node {
     has IO::Path:D() $.target is required;
@@ -38,9 +34,9 @@ class SymLink does Node {
     }
 }
 
-class Dir does Node {
-    has Node:D    @!children   is built;
-    has Instant:D $.cache-time .= from-posix-nanos(0);
+class Dir does Parent {
+    has Tree::Node:D @!children   is built;
+    has Instant:D    $.cache-time .= from-posix-nanos(0);
 
 
     #| Lazily find (and cache) children, forcing a refresh if requested
@@ -57,12 +53,9 @@ class Dir does Node {
                 .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 => $_) ;
+                        Misc.new(   parent => self, path => $_) ;
             };
         }
         @!children
     }
 }
-
-class Root is Dir {
-}

lib/Terminal/Widgets/Volatile/Tree.rakumod

@@ -0,0 +1,30 @@
+# ABSTRACT: Base roles for volatile tree data structures
+
+unit module Terminal::Widgets::Volatile::Tree;
+
+
+#| Basic generic tree node that knows its parent (if any)
+role Node {
+    has Node $.parent;
+
+    #| Shortened name for gists
+    method gist-name() {
+        self.^name.subst('Terminal::Widgets::', '')
+    }
+
+    #| Find root node via parent chain, runtime is O(depth)
+    method root(::?CLASS:D:) {
+        my $root = self;
+        $root .= parent while $root.parent;
+        $root
+    }
+}
+
+#| A pure leaf node, no children ever
+role Leaf does Node { }
+
+#| A parent node, which MAY have children at any given time
+role Parent does Node {
+    #| REQUIRED: Lazily find (and maybe cache) children, forcing a refresh if requested
+    method children(::?CLASS:D: Bool:D :$refresh = False) { ... }
+}