tomleo · August 7, 2012 01:10 · Aug 6, 2012 · Aug 4, 2012 · Aug 4, 2012 · Aug 4, 2012
diff --git a/Fun.java b/Fun.java
@@ -0,0 +1,23 @@
+
+// Demonstration of anonymous inner classes in Java
+// This is the closest thing Java has to function pointers.
+public class Fun {
+	public interface Procedure {
+		void execute();
+	}
+	static Procedure[] fun = new Procedure[256];
+	public static void main(String[] args) {
+		fun[0] = new Procedure() {
+			public void execute() {
+				System.out.println("Howdy!");
+			}
+		};
+		fun[1] = new Procedure() {
+			public void execute() {
+				System.out.println("But so is RUM");
+			}
+		};
+		fun[0].execute();
+		fun[1].execute();
+	}
+}
diff --git a/README.md b/README.md
@@ -39,7 +39,7 @@ It is NOT necessary to make multiple passes through the source code.
 This language (RUM) is not that complex.
 Don't forget to write (and test) the `CompilerVisitor` for valid RUM programs!
 
-Also: `byte` in Java is unsigned. To make byte `b` unsigned, do: `b & 0xFF`
+Also: `byte` in Java is signed. To make byte `b` unsigned, do: `b & 0xFF`
 
 Deadline and submission
 =======================

diff --git a/README.md b/README.md
@@ -12,6 +12,35 @@ FYI
 Your source code *MUST* be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working partial solution to last year's lab.
 You source code must also test that it works for valid RUM programs.
 
+Hints
+-----
+First, update the parser, `PrintVisitor` and `InterpreterVisitor` for the [pbrain](http://esolangs.org/wiki/Pbrain) subset of RUM.
+You'll need to add in two new Node types for procedure definition and invocation.
+Make sure it works with this program:
+
+    (++++++++++<[>+>+<<-]>>[<<+>>-])>::::::::::::::<<<<<<<--------.>>>---------.+++++++..>---------.<<<<<<<------.<--------.>>>>>---.>>>.+++.<.--------.<<<<<<<+.
+
+That program is "Hello, World!" in pbrain.
+
+In the `InterpreterVisitor` you'll need this:
+
+    private byte[] array;
+    private int pointer;
+    public interface Procedure {
+        void execute();
+    }
+    private Procedure[] procedures;
+
+Inside the visit method for Program, add this:
+
+    procedures = new Procedure[256];
+
+It is NOT necessary to make multiple passes through the source code.
+This language (RUM) is not that complex.
+Don't forget to write (and test) the `CompilerVisitor` for valid RUM programs!
+
+Also: `byte` in Java is unsigned. To make byte `b` unsigned, do: `b & 0xFF`
+
 Deadline and submission
 =======================
 You must complete this by the end of final exam time on August 10.

diff --git a/README.md b/README.md
@@ -12,6 +12,27 @@ FYI
 Your source code *MUST* be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working partial solution to last year's lab.
 You source code must also test that it works for valid RUM programs.
 
+Hints
+-----
+First, update the parser, `PrintVisitor` and `InterpreterVisitor` for the [pbrain](http://esolangs.org/wiki/Pbrain) subset of RUM.
+Make sure it works with this program:
+
+    (++++++++++<[>+>+<<-]>>[<<+>>-])>::::::::::::::<<<<<<<--------.>>>---------.+++++++..>---------.<<<<<<<------.<--------.>>>>>---.>>>.+++.<.--------.<<<<<<<+.
+
+That program is "Hello, World!" in pbrain.
+
+In the `InterpreterVisitor` you'll need this:
+
+    private byte[] array;
+    private int pointer;
+    public interface Procedure {
+        void execute();
+    }
+    private Procedure[] procedures;
+
+It is NOT necessary to make multiple passes through the source code.
+This language (RUM) is not that complex.
+
 Deadline and submission
 =======================
 You must complete this by the end of final exam time on August 10.

diff --git a/README.md b/README.md
@@ -16,6 +16,9 @@ Deadline and submission
 =======================
 You must complete this by the end of final exam time on August 10.
 However, do not wait until then to start.
-Submit your solution via email to <[email protected]>
+
+This is a final exam.
+It is individual work.
+Therefore, submit your solution via email to <[email protected]>
 
 If you submit your solution, and you do not receive email confirmation from me before August 10 that it works correctly, then you must attend the final exam period.
diff --git a/README.md b/README.md
@@ -5,7 +5,7 @@ Goal
 ----
 Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM). RUM is an extension of [pbrain](http://esolangs.org/wiki/Pbrain), which in turn is an extension of [brainf--k.](http://esolangs.org/wiki/Brainfuck)
 
-* Also, finish any two of the four tasks defined in [Lab1-BF.pdf]((https://gist.github.com/raw/2917371/b15802afcb7c992d757639f39526ea015dda6696/Lab1-BF.pdf).
+* Also, finish any two of the four tasks defined in [Lab1-BF.pdf](https://gist.github.com/raw/2917371/b15802afcb7c992d757639f39526ea015dda6696/Lab1-BF.pdf).
 
 FYI
 ---

diff --git a/README.md b/README.md
@@ -5,7 +5,7 @@ Goal
 ----
 Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM). RUM is an extension of [pbrain](http://esolangs.org/wiki/Pbrain), which in turn is an extension of [brainf--k.](http://esolangs.org/wiki/Brainfuck)
 
-* Also, finish any two of the four tasks defined in [Lab1-BF.pdf]((https://gist.github.com/raw/2917371/b15802afcb7c992d757639f39526ea015dda6696/Lab1-BF.pdf)).
+* Also, finish any two of the four tasks defined in [Lab1-BF.pdf]((https://gist.github.com/raw/2917371/b15802afcb7c992d757639f39526ea015dda6696/Lab1-BF.pdf).
 
 FYI
 ---

diff --git a/README.md b/README.md
@@ -9,7 +9,8 @@ Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM). RUM is
 
 FYI
 ---
-Your source code must be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working partial solution to last year's lab.
+Your source code *MUST* be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working partial solution to last year's lab.
+You source code must also test that it works for valid RUM programs.
 
 Deadline and submission
 =======================

diff --git a/README.md b/README.md
@@ -3,15 +3,13 @@ Final
 
 Goal
 ----
-Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM).
+Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM). RUM is an extension of [pbrain](http://esolangs.org/wiki/Pbrain), which in turn is an extension of [brainf--k.](http://esolangs.org/wiki/Brainfuck)
 
 * Also, finish any two of the four tasks defined in [Lab1-BF.pdf]((https://gist.github.com/raw/2917371/b15802afcb7c992d757639f39526ea015dda6696/Lab1-BF.pdf)).
 
 FYI
 ---
-RUM is an extension of [pbrain](http://esolangs.org/wiki/Pbrain), which in turn is an extension of [brainf--k.](http://esolangs.org/wiki/Brainfuck)
-
-Your source code must be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working solution to last year's lab.
+Your source code must be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working partial solution to last year's lab.
 
 Deadline and submission
 =======================

diff --git a/README.md b/README.md
@@ -1,11 +1,22 @@
 Final
 =====
 
+Goal
+----
 Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM).
+
+* Also, finish any two of the four tasks defined in [Lab1-BF.pdf]((https://gist.github.com/raw/2917371/b15802afcb7c992d757639f39526ea015dda6696/Lab1-BF.pdf)).
+
+FYI
+---
 RUM is an extension of [pbrain](http://esolangs.org/wiki/Pbrain), which in turn is an extension of [brainf--k.](http://esolangs.org/wiki/Brainfuck)
-Start from here: <https://gist.github.com/2917371>
-Complete Lab1 for RUM, and finish 2 of the tasks in Section 4.
 
-Deadline
-========
-Due August 10 at final exam time.
+Your source code must be based on [BF.java](https://raw.github.com/gist/2917371/19e8fa54cada3e1a5638b0f972cbc18f646dad8e/BF.java), a working solution to last year's lab.
+
+Deadline and submission
+=======================
+You must complete this by the end of final exam time on August 10.
+However, do not wait until then to start.
+Submit your solution via email to <[email protected]>
+
+If you submit your solution, and you do not receive email confirmation from me before August 10 that it works correctly, then you must attend the final exam period.
diff --git a/Lab1-BF.pdf b/Lab1-BF.pdf
diff --git a/README.md b/README.md
@@ -0,0 +1,11 @@
+Final
+=====
+
+Write a compiler and interpreter for [RUM](http://esolangs.org/wiki/RUM).
+RUM is an extension of [pbrain](http://esolangs.org/wiki/Pbrain), which in turn is an extension of [brainf--k.](http://esolangs.org/wiki/Brainfuck)
+Start from here: <https://gist.github.com/2917371>
+Complete Lab1 for RUM, and finish 2 of the tasks in Section 4.
+
+Deadline
+========
+Due August 10 at final exam time.
diff --git a/BF.java b/BF.java
@@ -0,0 +1,147 @@
+import java.io.IOException;
+import java.util.LinkedList;
+
+public class BF {
+	private interface Visitor {
+		void visit (Loop loop);
+		void visit (Left left);
+		void visit (Right right);
+		void visit (Increment increment);
+		void visit (Decrement decrement);
+		void visit (Input input);
+		void visit (Output output);
+		void visit (Program program);
+	}
+	private interface Node {
+		void accept (Visitor v);
+	}
+	private class Left implements Node {
+		public void accept (Visitor v) {
+			v.visit(this);
+		}
+	}
+	private class Right implements Node {
+		public void accept (Visitor v) {
+			v.visit(this);
+		}
+	}
+	private class Increment implements Node {
+		public void accept (Visitor v) {
+			v.visit(this);
+		}
+	}
+	private class Decrement implements Node {
+		public void accept (Visitor v) {
+			v.visit(this);
+		}
+	}
+	private class Input implements Node {
+		public void accept (Visitor v) {
+			v.visit(this);
+		}
+	}
+	private class Output implements Node {
+		public void accept (Visitor v) {
+			v.visit(this);
+		}
+	}
+	private class Sequence implements Node {
+		private LinkedList<Node> children;
+		public Sequence() {
+			children = new LinkedList<Node>();
+		}
+		public void accept (Visitor v) {
+			for (Node child : children) {
+				child.accept(v);
+			}
+		}
+		public void add (Node instruction) {
+			children.add(instruction);
+		}
+	}
+	private class Loop implements Node {
+		public Node body;
+		public Loop (Node body) {
+			this.body = body;
+		}
+		public void accept (Visitor v) {
+			v.visit (this);
+		}
+	}
+	public static class Program implements Node {
+		public Node body;
+		public Program (Node body) {
+			this.body = body;
+		}
+		public void accept(Visitor v) {
+			v.visit (this);
+		}
+	}
+	private int i = 0;
+	private Sequence doParse (String str) {
+		Sequence seq = new Sequence();
+		char c;
+		while (i < str.length ()) {
+			c = str.charAt (i);
+			i++;
+			if (c == '<') seq.add (new Left ());
+			if (c == '>') seq.add (new Right ());
+			if (c == '+') seq.add (new Increment ());
+			if (c == '-') seq.add (new Decrement ());
+			if (c == '.') seq.add (new Output ());
+			if (c == ',') seq.add (new Input ());
+			if (c == '[') seq.add (new Loop (doParse (str)));
+			if (c == ']') return seq;
+		}
+		return seq;
+	}
+	public static Program parse (String str) {
+		return new Program (new BF().doParse(str));
+	}
+	public static void main(String[] args) {
+		Node ascii = BF.parse("+[.+]");
+		ascii.accept(new BF.InterpreterVisitor());
+		Node hello = BF.parse("++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.");
+		hello.accept(new BF.InterpreterVisitor());
+		Node beer = BF.parse(">+++++++++[<+++++++++++>-]<[>[-]>[-]<<[>+>+<<-]>>[<<+>>-]>>>[-]<<<+++++++++<[>>>+<<[>+>[-]<<-]>[<+>-]>[<<++++++++++>>>+<-]<<-<-]+++++++++>[<->-]>>+>[<[-]<<+>>>-]>[-]+<<[>+>-<<-]<<<[>>+>+<<<-]>>>[<<<+>>>-]>[<+>-]<<-[>[-]<[-]]>>+<[>[-]<-]<++++++++[<++++++<++++++>>-]>>>[>+>+<<-]>>[<<+>>-]<[<<<<<.>>>>>-]<<<<<<.>>[-]>[-]++++[<++++++++>-]<.>++++[<++++++++>-]<++.>+++++[<+++++++++>-]<.><+++++..--------.-------.>>[>>+>+<<<-]>>>[<<<+>>>-]<[<<<<++++++++++++++.>>>>-]<<<<[-]>++++[<++++++++>-]<.>+++++++++[<+++++++++>-]<--.---------.>+++++++[<---------->-]<.>++++++[<+++++++++++>-]<.+++..+++++++++++++.>++++++++[<---------->-]<--.>+++++++++[<+++++++++>-]<--.-.>++++++++[<---------->-]<++.>++++++++[<++++++++++>-]<++++.------------.---.>+++++++[<---------->-]<+.>++++++++[<+++++++++++>-]<-.>++[<----------->-]<.+++++++++++..>+++++++++[<---------->-]<-----.---.>>>[>+>+<<-]>>[<<+>>-]<[<<<<<.>>>>>-]<<<<<<.>>>++++[<++++++>-]<--.>++++[<++++++++>-]<++.>+++++[<+++++++++>-]<.><+++++..--------.-------.>>[>>+>+<<<-]>>>[<<<+>>>-]<[<<<<++++++++++++++.>>>>-]<<<<[-]>++++[<++++++++>-]<.>+++++++++[<+++++++++>-]<--.---------.>+++++++[<---------->-]<.>++++++[<+++++++++++>-]<.+++..+++++++++++++.>++++++++++[<---------->-]<-.---.>+++++++[<++++++++++>-]<++++.+++++++++++++.++++++++++.------.>+++++++[<---------->-]<+.>++++++++[<++++++++++>-]<-.-.---------.>+++++++[<---------->-]<+.>+++++++[<++++++++++>-]<--.+++++++++++.++++++++.---------.>++++++++[<---------->-]<++.>+++++[<+++++++++++++>-]<.+++++++++++++.----------.>+++++++[<---------->-]<++.>++++++++[<++++++++++>-]<.>+++[<----->-]<.>+++[<++++++>-]<..>+++++++++[<--------->-]<--.>+++++++[<++++++++++>-]<+++.+++++++++++.>++++++++[<----------->-]<++++.>+++++[<+++++++++++++>-]<.>+++[<++++++>-]<-.---.++++++.-------.----------.>++++++++[<----------->-]<+.---.[-]<<<->[-]>[-]<<[>+>+<<-]>>[<<+>>-]>>>[-]<<<+++++++++<[>>>+<<[>+>[-]<<-]>[<+>-]>[<<++++++++++>>>+<-]<<-<-]+++++++++>[<->-]>>+>[<[-]<<+>>>-]>[-]+<<[>+>-<<-]<<<[>>+>+<<<-]>>>[<<<+>>>-]<>>[<+>-]<<-[>[-]<[-]]>>+<[>[-]<-]<++++++++[<++++++<++++++>>-]>>>[>+>+<<-]>>[<<+>>-]<[<<<<<.>>>>>-]<<<<<<.>>[-]>[-]++++[<++++++++>-]<.>++++[<++++++++>-]<++.>+++++[<+++++++++>-]<.><+++++..--------.-------.>>[>>+>+<<<-]>>>[<<<+>>>-]<[<<<<++++++++++++++.>>>>-]<<<<[-]>++++[<++++++++>-]<.>+++++++++[<+++++++++>-]<--.---------.>+++++++[<---------->-]<.>++++++[<+++++++++++>-]<.+++..+++++++++++++.>++++++++[<---------->-]<--.>+++++++++[<+++++++++>-]<--.-.>++++++++[<---------->-]<++.>++++++++[<++++++++++>-]<++++.------------.---.>+++++++[<---------->-]<+.>++++++++[<+++++++++++>-]<-.>++[<----------->-]<.+++++++++++..>+++++++++[<---------->-]<-----.---.+++.---.[-]<<<]");
+		beer.accept(new BF.InterpreterVisitor());
+		Node fibonacci = BF.parse("+++++++++++>+>>>>++++++++++++++++++++++++++++++++++++++++++++>++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>+<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-<-[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<[>>>+<<<-]>>[-]]<<]>>>[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<+>>[-]]<<<<<<<]>>>>>[++++++++++++++++++++++++++++++++++++++++++++++++.[-]]++++++++++<[->-<]>++++++++++++++++++++++++++++++++++++++++++++++++.[-]<<<<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<[-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]");
+		fibonacci.accept(new BF.InterpreterVisitor());
+		Node rot13 = BF.parse("+[,+[-[>+>+<<-]>[<+>-]+>>++++++++[<-------->-]<-[<[-]>>>+[<+<+>>-]<[>+<-]<[<++>>>+[<+<->>-]<[>+<-]]>[<]<]>>[-]<<<[[-]<[>>+>+<<<-]>>[<<+>>-]>>++++++++[<-------->-]<->>++++[<++++++++>-]<-<[>>>+<<[>+>[-]<<-]>[<+>-]>[<<<<<+>>>>++++[<++++++++>-]>-]<<-<-]>[<<<<[-]>>>>[<<<<->>>>-]]<<++++[<<++++++++>>-]<<-[>>+>+<<<-]>>[<<+>>-]+>>+++++[<----->-]<-[<[-]>>>+[<+<->>-]<[>+<-]<[<++>>>+[<+<+>>-]<[>+<-]]>[<]<]>>[-]<<<[[-]<<[>>+>+<<<-]>>[<<+>>-]+>------------[<[-]>>>+[<+<->>-]<[>+<-]<[<++>>>+[<+<+>>-]<[>+<-]]>[<]<]>>[-]<<<<<------------->>[[-]+++++[<<+++++>>-]<<+>>]<[>++++[<<++++++++>>-]<-]>]<[-]++++++++[<++++++++>-]<+>]<.[-]+>>+<]>[[-]<]<]");
+		rot13.accept(new BF.InterpreterVisitor());
+	}
+	public static class PrintVisitor implements Visitor {
+		public void visit (Left n) { System.out.print('<'); }
+		public void visit (Right n) { System.out.print('>'); }
+		public void visit (Increment n) { System.out.print('+'); }
+		public void visit (Decrement n) { System.out.print('-'); }
+		public void visit (Input n) { System.out.print(','); }
+		public void visit (Output n) { System.out.print('.'); }
+		public void visit (Loop n) { System.out.print('['); n.body.accept(this); System.out.print(']'); }
+		public void visit (Program n) { n.body.accept(this); }
+	}
+	public static class InterpreterVisitor implements Visitor {
+		private byte[] array;
+		private int pointer;
+
+		public void visit (Left n) { pointer--; }
+		public void visit (Right n) { pointer++; }
+		public void visit (Increment n) { array[pointer]++; }
+		public void visit (Decrement n) { array[pointer]--; }
+		public void visit (Input n) { try {
+			array[pointer] = (byte) System.in.read();
+		} catch (IOException e) {
+		} }
+		public void visit (Output n) { System.out.print((char)array[pointer]); }
+		public void visit (Loop n) {
+			while (array[pointer] != 0) {
+				n.body.accept(this);
+			}
+		}
+		public void visit (Program n) {
+			array = new byte[30000];
+			pointer = 0;
+			n.body.accept(this);
+		}
+	}
+}