// Main Part 5 about an Interpreter for 

// the Brainf*** language

//==============================================

object M5a {

// representation of BF memory 

type Mem = Map[Int, Int]

// (1) Write a function that takes a file name as argument and

// and requests the corresponding file from disk. It returns the

// content of the file as a String. If the file does not exists,

// the function should return the empty string.

import io.Source

import scala.util._

def load_bff(name: String) : String = ???

// (2) 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, provided 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 = ???

// (3) Implement the two jumping instructions in the 

// brainf*** language. In jumpRight, given a program and 

// a program counter move the program counter to the right 

// until after the *matching* ]-command. Similarly, 

// jumpLeft implements the move to the left to just after

// the *matching* [-command.

def jumpRight(prog: String, pc: Int, level: Int) : Int = ???

def jumpLeft(prog: String, pc: Int, level: Int) : Int = ???

// testcases

//jumpRight("""--[..+>--],>,++""", 3, 0)         // => 10

//jumpLeft("""--[..+>--],>,++""", 8, 0)          // => 3

//jumpRight("""--[..[+>]--],>,++""", 3, 0)       // => 12

//jumpRight("""--[..[[-]+>[.]]--],>,++""", 3, 0) // => 18

//jumpRight("""--[..[[-]+>[.]]--,>,++""", 3, 0)  // => 22 (outside)

//jumpLeft("""[******]***""", 7, 0)              // => -1 (outside)

// (4) Complete the compute function that interprets (runs) a brainf***

// program: the arguments are a program (represented as a string), 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 compute 

// function continues with the command at the new program

// counter. 

//

// Implement the run function that calls compute with the program

// counter and memory counter set to 0.

def compute(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = ???

def run(prog: String, m: Mem = Map()) = ???

// some sample bf-programs collected from the Internet

//=====================================================

// some contrived (small) programs

//---------------------------------

// clears the 0-cell

//run("[-]", Map(0 -> 100))    // Map will be 0 -> 0

// moves content of the 0-cell to 1-cell

//run("[->+<]", Map(0 -> 10))  // Map will be 0 -> 0, 1 -> 10

// copies content of the 0-cell to 2-cell and 4-cell

//run("[>>+>>+<<<<-]", Map(0 -> 42))    // Map(0 -> 0, 2 -> 42, 4 -> 42)

// prints out numbers 0 to 9

//run("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")

// some more "useful" programs

//-----------------------------

// hello world program 1

//run("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++

//       ..+++.>>.<-.<.+++.------.--------.>>+.>++.""")

// hello world program 2

//run("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+

//       +.<<+++++++++++++++.>.+++.------.--------.>+.>.""")

// hello world program 3

//run("""+++++++++[>++++++++>+++++++++++>+++++<<<-]>.>++.+++++++..

//       +++.>-.------------.<++++++++.--------.+++.------.--------.>+.""")

// draws the Sierpinski triangle

//run(load_bff("sierpinski.bf"))

//fibonacci numbers below 100

//run("""+++++++++++

//      >+>>>>++++++++++++++++++++++++++++++++++++++++++++

//      >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>

//      +<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-

//      <-[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]>[<<[>>>+<<<

//      -]>>[-]]<<]>>>[>>+>+<<<-]>>>[<<<+>>>-]+<[>[-]<[-]]

//      >[<<+>>[-]]<<<<<<<]>>>>>[+++++++++++++++++++++++++

//      +++++++++++++++++++++++.[-]]++++++++++<[->-<]>++++

//      ++++++++++++++++++++++++++++++++++++++++++++.[-]<<

//      <<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<

//      [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""")

//outputs the square numbers up to 10000

//run("""++++[>+++++<-]>[<+++++>-]+<+[>[>+>+<<-]++>>[<<+>>-]>>>[-]++>[-]+

//       >>>+[[-]++++++>>>]<<<[[<++++++++<++>>-]+<.<[>----<-]<]

//       <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]""")

// calculates 2 to the power of 6 

//(example from a C-to-BF compiler at https://github.com/elikaski/BF-it)

//run(""">>[-]>[-]++>[-]++++++><<<>>>>[-]+><>[-]<<[-]>[>+<<+>-]>[<+>-]

//       <><[-]>[-]<<<[>>+>+<<<-]>>>[<<<+>>>-][-]><<>>[-]>[-]<<<[>>[-]

//       <[>+>+<<-]>[<+>-]+>[[-]<-<->>]<<<-]>>[<<+>>-]<<[[-]>[-]<<[>+>

//       +<<-]>>[<<+>>-][-]>[-]<<<<<[>>>>+>+<<<<<-]>>>>>[<<<<<+>>>>>-]

//       <<>>[-]>[-]<<<[>>>+<<<-]>>>[<<[<+>>+<-]>[<+>-]>-]<<<>[-]<<[-]

//       >[>+<<+>-]>[<+>-]<><[-]>[-]<<<[>>+>+<<<-]>>>-[<<<+>>>-]<[-]>[-]

//       <<<[>>+>+<<<-]>>>[<<<+>>>-][-]><<>>[-]>[-]<<<[>>[-]<[>+>+<<-]>

//       [<+>-]+>[[-]<-<->>]<<<-]>>[<<+>>-]<<][-]>[-]<<[>+>+<<-]>>[<<+>

//       >-]<<<<<[-]>>>>[<<<<+>>>>-]<<<<><>[-]<<[-]>[>+<<+>-]>[<+>-]<>

//       <[-]>[-]>[-]<<<[>>+>+<<<-]>>>[<<<+>>>-]<<>>[-]>[-]>[-]>[-]>[-]>

//       [-]>[-]>[-]>[-]>[-]<<<<<<<<<<>>++++++++++<<[->+>-[>+>>]>[+[-<+

//       >]>+>>]<<<<<<]>>[-]>>>++++++++++<[->-[>+>>]>[+[-<+>]>+>>]<<<<<

//       ]>[-]>>[>++++++[-<++++++++>]<.<<+>+>[-]]<[<[->-<]++++++[->++++

//       ++++<]>.[-]]<<++++++[-<++++++++>]<.[-]<<[-<+>]<<><<<""")

// a Mandelbrot set generator in brainf*** written by Erik Bosman

// (http://esoteric.sange.fi/brainfuck/utils/mandelbrot/)

//

//run(load_bff("mandelbrot.bf"))

// a benchmark program (counts down from 'Z' to 'A')

//

//run(load_bff("benchmark.bf"))

// calculates the Collatz series for numbers from 1 to 30

//

//run(load_bff("collatz.bf"))

}