Reorganized repo for npm, better names for visitor pattern

.gitignore

@@ -1,3 +1,6 @@
 out
 .vscode
 .DS_Store
+*~
+node_modules/
+dist/

README.md

@@ -1 +1,35 @@
-# DesignPatternsExamples-Fall2020
+# DesignPatternsExamples-Fall2020
+
+This fork reorganizes the multiple examples for better use with VSCode, and
+two new variants on filesystem-visitor.
+
+1.  The various examples are now kept in the folder all-examples/ .  To run
+one or more of the examples, move its folder to live directly under src/ .
+I've updated the npm scripts so that "npm run run" will compile all .ts files
+contained in the directory tree under src, and will run all the
+dist/*/index.js files it finds.  [Thanks to Satya who showed me how to do
+this.]
+
+2. I've added a variant entitled filesystem-visitor-no-autorecursion.  I did
+not like the fact that recursion through directories was automatic. It's as
+if every "ls" was an "ls -R".   The -no-autorecursion removes the recursive
+calls to the visitor from directory.ts ; instead it adds a getChildren method
+to the Directory class, and the DuVisitor explicitly recurs on the children.
+
+3. I've added a variant entitled filesystem-visitor-better-names.  This is
+identical to filesystem-visitor-no-autorecursion except that
+
+  (a) "accept" in Node is now called "acceptVisitor", and
+  (b) visitFile, etc, are now called "ifFile".  I think these names make the
+  connection between the visitor pattern and a case structure clearer.
+
+  also
+  (c) duVisitor now takes one constructor argument, called startingNode, and its
+  constructor initiates the visit by calling
+  startingNode.acceptVisitor(this).
+
+  also
+  (d) I've cleaned up the code inside duVisitor to move all those private
+  variables out of the constructor where I don't think they belonged.
+
+Enjoy!

all-examples/filesystem-visitor-better-names/directory.ts

@@ -0,0 +1,29 @@
+import Node from './node'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+class Directory extends Node {
+
+  private children: Array<Node>;
+
+  constructor(n: string, p?: Directory){ 
+    super(n,p);
+    this.children = []; 
+  }
+  public getAbsoluteName() : string {
+    return super.getAbsoluteName() + "/";
+  } 
+
+  public getChildren(): Array<Node> { return this.children }
+
+  public add(n: Node) : void {
+    this.children.push(n); 
+  }
+  public acceptVisitor(v: IFileSystemVisitor) : void {
+    v.ifDirectory(this);
+    // no, it's up to the visitor to decide whether to recur on the children
+    // this.children.forEach((child) => child.accept(v))
+  }
+
+}
+
+export default Directory

all-examples/filesystem-visitor-better-names/duvisitor.ts

@@ -0,0 +1,36 @@
+import Node from './node'
+import File from './file'
+import Directory from './directory'
+import Link from './link'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+class DuVisitor implements IFileSystemVisitor {
+  private nrFiles = 0
+  private nrDirectories = 0
+  private nrLinks = 0
+  private totalSize = 0
+  constructor(startingNode: Node) {
+    startingNode.acceptVisitor(this);
+  }
+
+  public ifFile(f: File): void {
+    this.nrFiles++;
+    this.totalSize += f.size();
+  }
+  public ifDirectory(d: Directory): void {
+    this.nrDirectories++;
+    d.getChildren().forEach((child) => child.acceptVisitor(this))
+  }
+  public ifLink(l: Link): void {
+    this.nrLinks++;
+  }
+
+  public report(): void {
+    console.log("files:       " + this.nrFiles);
+    console.log("directories: " + this.nrDirectories);
+    console.log("links:       " + this.nrLinks);
+    console.log("total size:  " + this.totalSize);
+  }
+}
+
+export default DuVisitor

all-examples/filesystem-visitor-better-names/file.ts

@@ -0,0 +1,20 @@
+import Directory from './directory'
+import Node from './node'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+class File extends Node { 
+  private content: string
+
+  constructor(n: string, p: Directory, content: string){ 
+    super(n,p); 
+    this.content = content;
+  }
+  public acceptVisitor(v: IFileSystemVisitor) : void {
+    v.ifFile(this);
+  }
+  public size() : number {
+    return this.content.length;
+  }
+}
+
+export default File

all-examples/filesystem-visitor-better-names/ifilesystemvisitor.ts

@@ -0,0 +1,11 @@
+import Directory from './directory';
+import Link from './link';
+import File from './file'
+
+interface IFileSystemVisitor {
+  ifFile(f: File) : void;
+  ifDirectory(d: Directory): void;
+  ifLink(l: Link): void;
+}
+
+export default IFileSystemVisitor

all-examples/filesystem-visitor-better-names/index.ts

@@ -0,0 +1,20 @@
+import Directory from './directory'
+import File from './file'
+import Link from './link';
+import DuVisitor from './duvisitor';
+
+let root = new Directory("");
+new File("core", root, "hello");
+let usr = new Directory("usr", root);
+new File("adm", usr, "there");
+new Directory("foo", usr);
+new File("bar1", usr, "abcdef");
+new File("xbar2", usr, "abcdef");
+new File("yybarzz3", usr, "abcdef");
+let link = new Link("link", usr, root);
+new Link("link2", link, root);
+
+let visitor = new DuVisitor(root);
+// root.acceptVisitor(visitor);
+visitor.report();
+

all-examples/filesystem-visitor-better-names/link.ts

@@ -0,0 +1,20 @@
+import Directory from "./directory";
+import Node from "./node"
+import IFileSystemVisitor from "./ifilesystemvisitor";
+
+class Link extends Node { 
+  private realNode: Node;
+
+  constructor(n: string, w: Node, p: Directory){
+    super(n,p); 
+    this.realNode = w;  
+  }
+  public getAbsoluteName() : string{
+    return super.getAbsoluteName() + "@";
+  }   
+  public acceptVisitor(v: IFileSystemVisitor) : void {
+    v.ifLink(this);
+  } 
+}
+
+export default Link

all-examples/filesystem-visitor-better-names/node.ts

@@ -0,0 +1,22 @@
+import Directory from './directory'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+abstract class Node {
+  protected name: string;
+  protected parent: Directory;
+
+  constructor(name: string, parent: Directory) {
+    this.name = name; this.parent = parent;
+    if (this.parent != null) { this.parent.add(this); }
+  }
+  public getAbsoluteName() : string {
+    if (this.parent != null) {
+      return this.parent.getAbsoluteName() + this.name;
+    }
+    return this.name;
+  }
+  public toString() : string { return this.getAbsoluteName(); } 
+  public abstract acceptVisitor(v: IFileSystemVisitor) : void;
+}
+
+export default Node

all-examples/filesystem-visitor-no-auto-recursion/directory.ts

@@ -0,0 +1,29 @@
+import Node from './node'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+class Directory extends Node {
+
+  private children: Array<Node>;
+
+  constructor(n: string, p?: Directory){ 
+    super(n,p);
+    this.children = []; 
+  }
+  public getAbsoluteName() : string {
+    return super.getAbsoluteName() + "/";
+  } 
+
+  public getChildren(): Array<Node> { return this.children }
+
+  public add(n: Node) : void {
+    this.children.push(n); 
+  }
+  public accept(v: IFileSystemVisitor) : void {
+    v.visitDirectory(this);
+    // no, it's up to the visitor to decide whether to recur on the children
+    // this.children.forEach((child) => child.accept(v))
+  }
+
+}
+
+export default Directory

src/filesystem-visitor/duvisitor.ts → all-examples/filesystem-visitor-no-auto-recursion/duvisitor.ts

@@ -15,6 +15,7 @@ class DuVisitor implements IFileSystemVisitor {
   }
   public visitDirectory(d: Directory) : void {
     this.nrDirectories++;
+    d.getChildren().forEach((child) => child.accept(this))
   }
   public visitLink(l: Link) : void {
     this.nrLinks++;

all-examples/filesystem-visitor/duvisitor.ts

@@ -0,0 +1,34 @@
+import File from './file'
+import Directory from './directory'
+import Link from './link'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+class DuVisitor implements IFileSystemVisitor {
+
+  private nrFiles = 0
+  private nrDirectories = 0
+  private nrLinks = 0
+  private totalSize = 0
+
+  constructor() { }
+
+  public visitFile(f: File): void {
+    this.nrFiles++;
+    this.totalSize += f.size();
+  }
+  public visitDirectory(d: Directory): void {
+    this.nrDirectories++;
+  }
+  public visitLink(l: Link): void {
+    this.nrLinks++;
+  }
+
+  public report(): void {
+    console.log("files:       " + this.nrFiles);
+    console.log("directories: " + this.nrDirectories);
+    console.log("links:       " + this.nrLinks);
+    console.log("total size:  " + this.totalSize);
+  }
+}
+
+export default DuVisitor

all-examples/filesystem-visitor/file.ts

@@ -0,0 +1,20 @@
+import Directory from './directory'
+import Node from './node'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+class File extends Node { 
+  private content: string
+
+  constructor(n: string, p: Directory, content: string){ 
+    super(n,p); 
+    this.content = content;
+  }
+  public accept(v: IFileSystemVisitor) : void {
+    v.visitFile(this);
+  }
+  public size() : number {
+    return this.content.length;
+  }
+}
+
+export default File

all-examples/filesystem-visitor/ifilesystemvisitor.ts

@@ -0,0 +1,11 @@
+import Directory from './directory';
+import Link from './link';
+import File from './file'
+
+interface IFileSystemVisitor {
+  visitFile(f: File) : void;
+  visitDirectory(d: Directory): void;
+  visitLink(l: Link): void;
+}
+
+export default IFileSystemVisitor

all-examples/filesystem-visitor/index.ts

@@ -0,0 +1,20 @@
+import Directory from './directory'
+import File from './file'
+import Link from './link';
+import DuVisitor from './duvisitor';
+
+let root = new Directory("");
+new File("core", root, "hello");
+let usr = new Directory("usr", root);
+new File("adm", usr, "there");
+new Directory("foo", usr);
+new File("bar1", usr, "abcdef");
+new File("xbar2", usr, "abcdef");
+new File("yybarzz3", usr, "abcdef");
+let link = new Link("link", usr, root);
+new Link("link2", link, root);
+
+let visitor = new DuVisitor();
+root.accept(visitor);
+visitor.report();
+

all-examples/filesystem-visitor/link.ts

@@ -0,0 +1,20 @@
+import Directory from "./directory";
+import Node from "./node"
+import IFileSystemVisitor from "./ifilesystemvisitor";
+
+class Link extends Node { 
+  private realNode: Node;
+
+  constructor(n: string, w: Node, p: Directory){
+    super(n,p); 
+    this.realNode = w;  
+  }
+  public getAbsoluteName() : string{
+    return super.getAbsoluteName() + "@";
+  }   
+  public accept(v: IFileSystemVisitor) : void {
+    v.visitLink(this);
+  } 
+}
+
+export default Link

all-examples/filesystem-visitor/node.ts

@@ -0,0 +1,22 @@
+import Directory from './directory'
+import IFileSystemVisitor from './ifilesystemvisitor';
+
+abstract class Node {
+  protected name: string;
+  protected parent: Directory;
+
+  constructor(name: string, parent: Directory) {
+    this.name = name; this.parent = parent;
+    if (this.parent != null) { this.parent.add(this); }
+  }
+  public getAbsoluteName() : string {
+    if (this.parent != null) {
+      return this.parent.getAbsoluteName() + this.name;
+    }
+    return this.name;
+  }
+  public toString() : string { return this.getAbsoluteName(); } 
+  public abstract accept(v: IFileSystemVisitor) : void;
+}
+
+export default Node