--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/template3/bf.scala	Thu Dec 07 12:04:31 2017 +0000
@@ -0,0 +1,151 @@
+// Part 2 about an Interpreter for the Brainf*** language
+//========================================================
+
+object CW8b {
+
+type Mem = Map[Int, Int]
+
+// (2a) Complete the functions for safely reading  
+// and writing brainf*** memory. Safely read should
+// Return the value stored in the Map for a given memory
+// pointer, if it exists; otherwise it Returns 0. The
+// writing function generates a new Map with the
+// same data, except at the given memory pointer the
+// value v is stored.
+
+
+//def sread(mem: Mem, mp: Int) : Int = ...
+
+//def write(mem: Mem, mp: Int, v: Int) : Mem = ...
+
+
+// (2b) Implement the two jumping instructions in the 
+// brainf*** language. In jumpRight, given a program and 
+// a program counter move the counter to the right 
+// until the command after the *matching* ]-command. Similarly, 
+// jumpLeft implements the move to the left to just after
+// the *matching* [-command. The levels are used to find the
+// *matching* bracket.
+
+//def jumpRight(prog: String, pc: Int, level: Int) : Int = ...
+
+//def jumpLeft(prog: String, pc: Int, level: Int) : Int = ...
+
+
+
+// (2c) Complete the run function that interprets (runs) a brainf***
+// program: the arguments are a program, a program counter,
+// a memory counter and a brainf*** memory. It Returns the
+// memory at the stage when the execution of the brainf*** program
+// finishes. The interpretation finishes once the program counter
+// pc is pointing to something outside the program string.
+// If the pc points to a character inside the program, the pc, 
+// memory pointer and memory need to be updated according to 
+// rules of the brainf*** language. Then, recursively, the run 
+// function continues with the command at the new program
+// counter. 
+//
+// Implement the start function that calls run with the program
+// counter and memory counter set to 0.
+
+//def run(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = ...
+
+//def start(prog: String, mem: Mem) = ...
+
+
+
+
+
+
+// some sample bf programs collected from the Internet
+//==================================================
+
+
+/*
+// first some contrived (small) programs
+
+// clears the 0-cell
+start("[-]", Map(0 -> 100)) 
+
+// copies content of the 0-cell to 1-cell
+start("[->+<]", Map(0 -> 10))
+
+// copies content of the 0-cell to 2-cell and 4-cell
+start("[>>+>>+<<<<-]", Map(0 -> 42))
+
+start("+++[>+++++<-]", Map(0 -> 10))
+
+
+// prints out numbers 0 to 9
+start("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""", Map())
+
+
+// some more "useful" programs
+
+// hello world program 1
+start("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++
+       ..+++.>>.<-.<.+++.------.--------.>>+.>++.""", Map())
+
+// hello world program 2
+start("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+
+      +.<<+++++++++++++++.>.+++.------.--------.>+.>.""", Map())
+
+
+// draws the Sierpinski triangle
+start("""++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[
+      ->[+[-]+>++>>>-<<]<[<]>>++++++[<<+++++>>-]+<<++.[-]<<
+      ]>.>+[>>]>+]""", Map())
+
+//Fibonacci numbers below 100
+start("""+++++++++++
+      >+>>>>++++++++++++++++++++++++++++++++++++++++++++
+      >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>
+      +<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-
+      <-[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<[>>>+<<<
+      -]>>[-]]<<]>>>[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]
+      >[<<+>>[-]]<<<<<<<]>>>>>[+++++++++++++++++++++++++
+      +++++++++++++++++++++++.[-]]++++++++++<[->-<]>++++
+      ++++++++++++++++++++++++++++++++++++++++++++.[-]<<
+      <<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<
+      [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""", Map())
+
+
+//outputs the square numbers up to 10000
+start("""++++[>+++++<-]>[<+++++>-]+<+[
+    >[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+
+    >>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]
+    <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]""", Map())
+
+
+//Collatz numbers (need to be typed in)
+start(""">,[[----------[
+      >>>[>>>>]+[[-]+<[->>>>++>>>>+[>>>>]++[->+<<<<<]]<<<]
+      ++++++[>------<-]>--[>>[->>>>]+>+[<<<<]>-],<]>]>>>++>+>>[
+      <<[>>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<<]]<[>+<-]>]
+      >[>[>>>>]+[[-]<[+[->>>>]>+<]>[<+>[<<<<]]+<<<<]>>>[->>>>]+>+[<<<<]]
+      >[[>+>>[<<<<+>>>>-]>]<<<<[-]>[-<<<<]]>>>>>>>
+      ]>>+[[-]++++++>>>>]<<<<[[<++++++++>-]<.[-]<[-]<[-]<]<,]""", Map())
+
+
+// infinite Collatz (never stops)
+start(""">>+>+<[[->>[>>]>>>[>>]+[<<]<<<[<<]>[>[>>]>>+>[>>]<+<[<<]<<<[<
+      <]>-]>[>>]>>[<<<<[<<]>+>[>>]>>-]<<<<[<<]+>>]<<[+++++[>+++++++
+      +<-]>.<++++++[>--------<-]+<<]>>[>>]+[>>>>[<<+>+>-]<-[>+<-]+<
+      [<<->>-[<<+>>[-]]]>>>[<<<+<<+>>>>>-]<<<[>>>+<<<-]<<[[-]>+>>->
+      [<+<[<<+>>-]<[>+<-]<[>+<-]>>>>-]<[>+<-]+<[->[>>]<<[->[<+++>-[
+      <+++>-[<+++>-[<[-]++>>[-]+>+<<-[<+++>-[<+++>-[<[-]+>>>+<<-[<+
+      ++>-[<+++>-]]]]]]]]]<[>+<-]+<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<
+      +>-[<+>-[<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-[<+>-]]]]]]]]]]]<[>+<-
+      ]+>>]<<[<<]>]<[->>[->+>]<[-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<-
+      >>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>
+      -[<->>+<-[<+>-[<->>+<-[<+>-]]]]]]]]]]]]]]]]]]]>[<+>-]<+<[<+++
+      +++++++>-]<]>>[<+>->>]<<[>+>+<<-]>[<+>-]+>[<->[-]]<[-<<-]<<[<
+      <]]++++++[>+++++++<-]>++.------------.[-]>[>>]<<[+++++[>+++++
+      +++<-]>.<++++++[>--------<-]+<<]+<]>[<+>-]<]>>>[>>]<<[>[-]<-<
+      <]++++++++++.[-]<<<[<<]>>>+<[->[<+>-[<+>-[<+>-[<+>-[<+>-[<+>-
+      [<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-]]]]]]]]]]<[>+<-]+>>]<<[<<]>>]""", Map())
+
+
+*/ 
+
+}