--- a/progs/bfi.scala Mon Jul 20 10:06:43 2020 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,93 +0,0 @@
-// An Interpreter for BF*** Programs
-//===================================
-
-import io.Source
-import scala.util._
-
-// loding a bf-file
-def load_bff(name: String) : String =
- Try(Source.fromFile(name)("ISO-8859-1").mkString).getOrElse("")
-
-// BF memory as a map
-type Mem = Map[Int, Int]
-
-// reading and writing BF memory
-def sread(mem: Mem, mp: Int) : Int =
- mem.getOrElse(mp, 0)
-
-def write(mem: Mem, mp: Int, v: Int) : Mem =
- mem.updated(mp, v)
-
-
-// Right and Left Jumps in BF loops
-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)
- }
-}
-
-// main interpreter loop
-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 '[' => 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 run(prog: String, m: Mem = Map()) = compute(prog, 0, 0, m)
-
-// helper code for timing information
-def time_needed[T](n: Int, code: => T) = {
- val start = System.nanoTime()
- for (i <- 0 until n) code
- val end = System.nanoTime()
- (end - start)/(n * 1.0e9)
-}
-
-// Testcases
-//===========
-
-// a Mandelbrot set generator in brainf*** written by Erik Bosman
-// (http://esoteric.sange.fi/brainfuck/utils/mandelbrot/)
-val b0 = load_bff("mandelbrot.bf")
-
-println(s"${time_needed(1, run(b0))} secs")
-
-
-// a benchmark program (counts down from 'Z' to 'A')
-val b1 = """>++[<+++++++++++++>-]<[[>+>+<<-]>[<+>-]++++++++
- [>++++++++<-]>.[-]<<>++++++++++[>++++++++++[>++
- ++++++++[>++++++++++[>++++++++++[>++++++++++[>+
- +++++++++[-]<-]<-]<-]<-]<-]<-]<-]++++++++++."""
-
-println(s"${time_needed(1, run(b1))} secs")
-