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