--- a/templates5/bfc.scala Sun Nov 01 01:21:31 2020 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,165 +0,0 @@
-// Core Part about a "Compiler" for the Brainf*** language
-//======================================================
-
-
-object CW10b {
-
-
-// !!! Copy any function you need from file bf.scala !!!
-//
-// If you need any auxiliary function, feel free to
-// implement it, but do not make any changes to the
-// templates below.
-
-
-// DEBUGGING INFORMATION FOR COMPILERS!!!
-//
-// Compiler, even real ones, are fiendishly difficult to get
-// to produce correct code. One way to debug them is to run
-// example programs ``unoptimised''; and then optimised. Does
-// the optimised version still produce the same result?
-
-
-// for timing purposes
-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)
-}
-
-
-type Mem = Map[Int, Int]
-
-import io.Source
-import scala.util._
-
-
-// TASKS
-//=======
-
-// (5) Write a function jtable that precomputes the "jump
-// table" for a bf-program. This function takes a bf-program
-// as an argument and Returns a Map[Int, Int]. The
-// purpose of this map is to record the information about
-// pc positions where '[' or a ']' are stored. The information
-// is to which pc-position do we need to jump next?
-//
-// For example for the program
-//
-// "+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]"
-//
-// we obtain the map
-//
-// Map(69 -> 61, 5 -> 20, 60 -> 70, 27 -> 44, 43 -> 28, 19 -> 6)
-//
-// This states that for the '[' on position 5, we need to
-// jump to position 20, which is just after the corresponding ']'.
-// Similarly, for the ']' on position 19, we need to jump to
-// position 6, which is just after the '[' on position 5, and so
-// on. The idea is to not calculate this information each time
-// we hit a bracket, but just look up this information in the
-// jtable. You can use the jumpLeft and jumpRight functions
-// from Part 1 for calculating the jtable.
-//
-// Then adapt the compute and run functions from Part 1
-// in order to take advantage of the information stored in the jtable.
-// This means whenever jumpLeft and jumpRight was called previously,
-// you should immediately look up the jump address in the jtable.
-
-
-//def jtable(pg: String) : Map[Int, Int] = ...
-
-
-// testcase
-//
-// jtable("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")
-// => Map(69 -> 61, 5 -> 20, 60 -> 70, 27 -> 44, 43 -> 28, 19 -> 6)
-
-
-//def compute2(pg: String, tb: Map[Int, Int], pc: Int, mp: Int, mem: Mem) : Mem = ...
-//def run2(pg: String, m: Mem = Map()) = ...
-
-
-// testcases
-// time_needed(1, run2(load_bff("benchmark.bf")))
-// time_needed(1, run2(load_bff("sierpinski.bf")))
-
-
-
-// (6) Write a function optimise which deletes "dead code" (everything
-// that is not a bf-command) and also replaces substrings of the form
-// [-] by a new command 0. The idea is that the loop [-] just resets the
-// memory at the current location to 0. In the compute3 and run3 functions
-// below you implement this command by writing the number 0 to mem(mp),
-// that is write(mem, mp, 0).
-//
-// The easiest way to modify a string in this way is to use the regular
-// expression """[^<>+-.,\[\]]""", which recognises everything that is
-// not a bf-command and replace it by the empty string. Similarly the
-// regular expression """\[-\]""" finds all occurrences of [-] and
-// by using the Scala method .replaceAll you can replace it with the
-// string "0" standing for the new bf-command.
-
-//def optimise(s: String) : String = ...
-
-//def compute3(pg: String, tb: Map[Int, Int], pc: Int, mp: Int, mem: Mem) : Mem = ...
-
-//def run3(pg: String, m: Mem = Map()) = ...
-
-
-// testcases
-//
-// optimise(load_bff("benchmark.bf")) // should have inserted 0's
-// optimise(load_bff("mandelbrot.bf")).length // => 11203
-//
-// time_needed(1, run3(load_bff("benchmark.bf")))
-
-
-
-// (7) Write a function combine which replaces sequences
-// of repeated increment and decrement commands by appropriate
-// two-character commands. For example for sequences of +
-//
-// orig bf-cmds | replacement
-// ------------------------------
-// + | +A
-// ++ | +B
-// +++ | +C
-// |
-// ... |
-// |
-// +++....+++ | +Z
-// (where length = 26)
-//
-// Similar for the bf-command -, > and <. All other commands should
-// be unaffected by this change.
-//
-// Adapt the compute4 and run4 functions such that they can deal
-// appropriately with such two-character commands.
-
-
-//def combine(s: String) : String = ...
-
-// testcase
-// combine(load_bff("benchmark.bf"))
-
-
-//def compute4(pg: String, tb: Map[Int, Int], pc: Int, mp: Int, mem: Mem) : Mem = ...
-
-
-// should call first optimise and then combine on the input string
-//
-//def run4(pg: String, m: Mem = Map()) = ...
-
-
-// testcases
-// combine(optimise(load_bff("benchmark.bf"))) // => """>A+B[<A+M>A-A]<A[[....."""
-
-// testcases (they should now run much faster)
-// time_needed(1, run4(load_bff("benchmark.bf")))
-// time_needed(1, run4(load_bff("sierpinski.bf")))
-// time_needed(1, run4(load_bff("mandelbrot.bf")))
-
-
-}