--- a/main_testing5/bf.scala Sun Jan 15 10:58:13 2023 +0000
+++ b/main_testing5/bf.scala Sat Mar 11 22:01:53 2023 +0000
@@ -1,163 +1,164 @@
-// Core Part about an Interpreter for
-// the Brainf***++ language
+// Main Part 5 about an Interpreter for
+// the Brainf*** language
//==============================================
-object M5a {
-
-// representation of Bf memory
+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 =
- Try(Source.fromFile(name)("ISO-8859-1").mkString).getOrElse("")
-
+// ADD YOUR CODE BELOW
+//======================
-// (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)
+// (1)
+def load_bff(name: String) : String = {
+ Try(Source.fromFile(name)("ISO-8859-1").mkString).getOrElse("")
+}
-def write(mem: Mem, mp: Int, v: Int) : Mem =
- mem.updated(mp, v)
-
+// (2)
-// (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 sread(mem: Mem, mp: Int) : Int = {
+ Try(mem.apply(mp)).getOrElse(0)
+}
-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 write(mem: Mem, mp: Int, v: Int) : Mem = {
+ mem + (mp -> v)
}
-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)
- }
+// sread(Map(), 2) == 0
+// sread(Map(2 -> 1), 2) == 1
+// write(Map(), 1, 2) == Map(1 -> 2)
+// write(Map(1 -> 0), 1, 2) == Map(1 -> 2)
+
+// val current = sread(Map(2 -> 1), 2)
+// write(Map(2 -> 1), 2, current+1)
+
+// (3)
+
+def jumpRight(prog: String, pc: Int, level: Int) : Int = prog.toList.apply(pc) match{
+ case '[' => jumpRight(prog, pc+1, level+1)
+ case ']' => level match {
+ case 0 => pc+1
+ case _ => if (pc+1 >= prog.length) prog.length else jumpRight(prog, pc+1, level-1)
+ }
+ case _ => if (pc+1 >= prog.length) prog.length else jumpRight(prog, pc+1, level)
}
-// 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 '[' =>
- 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)
-
- case _ => (pc + 1, mp, mem)
- }
- compute(prog, new_pc, new_mp, new_mem)
- }
- else mem
+def jumpLeft(prog: String, pc: Int, level: Int) : Int = prog.toList.apply(pc) match{
+ case ']' => jumpLeft(prog, pc-1, level+1)
+ case '[' => level match {
+ case 0 => pc+1
+ case _ => if (pc-1 < 0) -1 else jumpLeft(prog, pc-1, level-1)
+ }
+ case _ => if (pc-1 < 0) -1 else jumpLeft(prog, pc-1, level)
}
-def run(prog: String, m: Mem = Map()) = compute(prog, 0, 0, m)
+
+// 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)
+def compute(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = (pc >= 0 && pc < prog.length) match {
+ case false => mem
+ case true => prog.toList.apply(pc) match{
+ case '>' => compute(prog, pc+1, mp+1, mem)
+ case '<' => compute(prog, pc+1, mp-1, mem)
+ case '+' => {
+ val current = sread(mem, mp)
+ compute(prog, pc+1, mp, write(mem, mp, current+1))
+ }
+ case '-' => {
+ val current = sread(mem, mp)
+ compute(prog, pc+1, mp, write(mem, mp, current-1))
+ }
+ case '.' => {
+ print(mem.apply(mp).toChar)
+ compute(prog, pc+1, mp, mem)
+ }
+ case '[' => {
+ if (mem.apply(mp) == 0) compute(prog, jumpRight(prog, pc+1, 0), mp, mem)
+ else compute(prog, pc+1, mp, mem)
+ }
+ case ']' => {
+ if (mem.apply(mp) != 0) compute(prog, jumpLeft(prog, pc-1, 0), mp, mem)
+ else compute(prog, pc+1, mp, mem)
+ }
+ case _ => compute(prog, pc, mp, mem)
+ }
+}
-// some sample bf/bf++-programs collected from the Internet
-//==========================================================
+def run(prog: String, m: Mem = Map()) = {
+ compute(prog, 0, 0, m)
+}
+
+// run("[-]", Map(0 -> 100)) == Map(0 -> 0)
+// run("[->+<]", Map(0 -> 10)) == Map(0 -> 0, 1 -> 10)
+// run("[>>+>>+<<<<-]", Map(0 -> 42)) == Map(0 -> 0, 2 -> 42, 4 -> 42)
+// run("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""") == Map(0 -> 0, 1 -> 58, 2 -> 32)
+
+// (5)
+def generate(msg: List[Char]) : String = msg match {
+ case Nil => ""
+ case c => "+"*c.head.toInt + ".[-]" + generate(msg.tail)
+}
+
+// generate("ABC".toList)
+
+// run("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.[-]++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.[-]+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.[-]", 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
+// // 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
+// // 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)
+// // 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("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")
+// // prints out numbers 0 to 9
+// run("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")
-// some more "useful" programs
-//-----------------------------
+// // some more "useful" programs
+// //-----------------------------
-// hello world program 1
-//run("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++
-// ..+++.>>.<-.<.+++.------.--------.>>+.>++.""")
+// // hello world program 1
+// run("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.""")
-// hello world program 2
-//run("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+
-// +.<<+++++++++++++++.>.+++.------.--------.>+.>.""")
+// // hello world program 2
+// run("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>.""")
-// hello world program 3
-//run("""+++++++++[>++++++++>+++++++++++>+++++<<<-]>.>++.+++++++..
-// +++.>-.------------.<++++++++.--------.+++.------.--------.>+.""")
+// // hello world program 3
+// run("""+++++++++[>++++++++>+++++++++++>+++++<<<-]>.>++.+++++++..+++.>-.------------.<++++++++.--------.+++.------.--------.>+.""")
-// draws the Sierpinski triangle
-//run(load_bff("sierpinski.bf"))
+// // draws the Sierpinski triangle
+// run(load_bff("sierpinski.bf"))
-//fibonacci numbers below 100
-//run("""+++++++++++
+// //fibonacci numbers below 100
+// run("""+++++++++++
// >+>>>>++++++++++++++++++++++++++++++++++++++++++++
// >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>
// +<<<<<<<-]>>>>>>>[<<<<<<<+>>>>>>>-]<[>++++++++++[-
@@ -169,15 +170,15 @@
// <<<<<<<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<-[>>.>.<<<
// [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""")
-//outputs the square numbers up to 10000
-//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(""">>[-]>[-]++>[-]++++++><<<>>>>[-]+><>[-]<<[-]>[>+<<+>-]>[<+>-]
+// // calculates 2 to the power of 6
+// // (example from a C-to-BF compiler at https://github.com/elikaski/BF-it)
+// run(""">>[-]>[-]++>[-]++++++><<<>>>>[-]+><>[-]<<[-]>[>+<<+>-]>[<+>-]
// <><[-]>[-]<<<[>>+>+<<<-]>>>[<<<+>>>-][-]><<>>[-]>[-]<<<[>>[-]
// <[>+>+<<-]>[<+>-]+>[[-]<-<->>]<<<-]>>[<<+>>-]<<[[-]>[-]<<[>+>
// +<<-]>>[<<+>>-][-]>[-]<<<<<[>>>>+>+<<<<<-]>>>>>[<<<<<+>>>>>-]
@@ -194,18 +195,28 @@
-// a Mandelbrot set generator in brainf*** written by Erik Bosman
+// // a Mandelbrot set generator in brainf*** written by Erik Bosman
// (http://esoteric.sange.fi/brainfuck/utils/mandelbrot/)
-//
-//run(load_bff("mandelbrot.bf"))
+
+// run(load_bff("mandelbrot.bf"))
-// a benchmark program (counts down from 'Z' to 'A')
-//
-//run(load_bff("benchmark.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"))
+// // calculates the Collatz series for numbers from 1 to 30
+// //
+// run(load_bff("collatz.bf"))
}
+
+
+
+
+
+// This template code is subject to copyright
+// by King's College London, 2022. Do not
+// make the template code public in any shape
+// or form, and do not exchange it with other
+// students under any circumstance.