--- a/solutions5/bf.scala Mon Nov 02 02:31:44 2020 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,227 +0,0 @@
-// Core Part about an Interpreter for
-// the Brainf***++ language
-//==============================================
-
-object CW10a {
-
-
-// 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 =
- Try(Source.fromFile(name)("ISO-8859-1").mkString).getOrElse("")
-
-
-// (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 =
- mem.getOrElse(mp, 0)
-
-def write(mem: Mem, mp: Int, v: Int) : Mem =
- mem.updated(mp, v)
-
-
-// (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 = {
- if (prog.length <= pc) pc
- else (prog(pc), level) match {
- case (']', 0) => pc + 1
- case (']', l) => jumpRight(prog, pc + 1, l - 1)
- case ('[', l) => jumpRight(prog, pc + 1, l + 1)
- case (_, l) => jumpRight(prog, pc + 1, l)
- }
-}
-
-def jumpLeft(prog: String, pc: Int, level: Int) : Int = {
- if (pc < 0) pc
- else (prog(pc), level) match {
- case ('[', 0) => pc + 1
- case ('[', l) => jumpLeft(prog, pc - 1, l - 1)
- case (']', l) => jumpLeft(prog, pc - 1, l + 1)
- case (_, l) => jumpLeft(prog, pc - 1, l)
- }
-}
-
-// test cases
-//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 = {
- if (0 <= pc && pc < prog.length) {
- val (new_pc, new_mp, new_mem) = prog(pc) match {
- case '>' => (pc + 1, mp + 1, mem)
- case '<' => (pc + 1, mp - 1, mem)
- case '+' => (pc + 1, mp, write(mem, mp, sread(mem, mp) + 1))
- case '-' => (pc + 1, mp, write(mem, mp, sread(mem, mp) - 1))
- case '.' => { print(sread(mem, mp).toChar); (pc + 1, mp, mem) }
- //case ',' => (pc + 1, mp, write(mem, mp, Console.in.read().toByte))
- //case ',' => (pc + 1, mp, write(mem, mp, scala.io.StdIn.readByte()))
- case '[' =>
- if (sread(mem, mp) == 0) (jumpRight(prog, pc + 1, 0), mp, mem) else (pc + 1, mp, mem)
- case ']' =>
- if (sread(mem, mp) != 0) (jumpLeft(prog, pc - 1, 0), mp, mem) else (pc + 1, mp, mem)
-
- // new commands
- case '@' => (pc + 1, mp, write(mem, sread(mem, mp), sread(mem, mp - 1)))
- case '*' => (pc + 1, mp, write(mem, mp, sread(mem, mp) * sread(mem, mp -1)))
- case '#' => { println(s"${sread(mem, mp)}"); (pc + 1, mp, mem) }
-
- case _ => (pc + 1, mp, mem)
- }
- compute(prog, new_pc, new_mp, new_mem)
- }
- else mem
-}
-
-def run(prog: String, m: Mem = Map()) = compute(prog, 0, 0, m)
-
-
-
-
-
-// some sample bf/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("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")
-
-// bf++ program calculating the cube-function, 10 * 10 * 10 = 1000
-//run("""++++++++++#>+***#""") // Map(0 -> 10, 1 -> 1000)
-
-
-// bf++ program copies 3 from 0-cell to to cells 1, 4, 5, 6 and 7
-// (note that because of how the program wprks cell 1 will contain 7)
-//run("""+++>+@+@+@+@+@""") // Map(0 -> 3, 1 -> 7, 4 -> 3, 5 -> 3, 6 -> 3, 7 -> 3)
-
-
-
-// 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"))
-
-}