[14727] | 1 | namespace HeuristicLab.Problems.ProgramSynthesis.Push.Expressions {
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| 2 | using Attributes;
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| 3 | using Interpreter;
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| 4 | using Stack;
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| 5 |
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| 6 | public abstract class DoRangeExpression : LoopExpression {
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| 7 | protected DoRangeExpression() { }
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| 8 | protected DoRangeExpression(LoopState state) : base(state) { }
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[14733] | 9 | protected override bool HasInsufficientArguments(IPushInterpreter interpreter, IStack<Expression> sourceStack) {
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[14727] | 10 | return interpreter.IntegerStack.Count < 2 ||
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| 11 | sourceStack.Count == 0 ||
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| 12 | interpreter.IntegerStack.Top == interpreter.IntegerStack.ReverseElementAt(1);
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| 13 | }
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| 14 |
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[14733] | 15 | protected override LoopState InitState(IPushInterpreter interpreter, IStack<Expression> sourceStack) {
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[14727] | 16 | var destinationIndex = interpreter.IntegerStack.Pop();
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| 17 | var incrementor = destinationIndex < interpreter.IntegerStack.Top ? -1 : 1;
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| 18 |
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| 19 | return new LoopState(
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| 20 | body: sourceStack.Pop(),
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| 21 | currentIndex: interpreter.IntegerStack.Top + incrementor,
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| 22 | destinationIndex: destinationIndex,
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| 23 | incrementor: incrementor);
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| 24 | }
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| 25 | }
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| 26 |
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| 27 | /// <summary>
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| 28 | /// An iteration instruction that executes the top item on the CODE stack a number of times that depends on the
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| 29 | /// top two integers, while also pushing the loop counter onto the INTEGER stack for possible access during the
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| 30 | /// execution of
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| 31 | /// the body of the loop. The top integer is the "destination index" and the second integer is the "current index."
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| 32 | /// First the code
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| 33 | /// and the integer arguments are saved locally and popped. Then the integers are compared. If the integers are equal
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| 34 | /// then the current
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| 35 | /// index is pushed onto the INTEGER stack and the code (which is the "body" of the loop) is pushed onto the EXEC stack
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| 36 | /// for subsequent
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| 37 | /// execution. If the integers are not equal then the current index will still be pushed onto the INTEGER stack but two
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| 38 | /// items will be
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| 39 | /// pushed onto the EXEC stack -- first a recursive call to CODE.DO*RANGE (with the same code and destination index,
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| 40 | /// but with a current
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| 41 | /// index that has been either incremented or decremented by 1 to be closer to the destination index) and then the body
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| 42 | /// code. Note that
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| 43 | /// the range is inclusive of both endpoints; a call with integer arguments 3 and 5 will cause its body to be executed
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| 44 | /// 3 times, with the
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| 45 | /// loop counter having the values 3, 4, and 5. Note also that one can specify a loop that "counts down" by providing a
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| 46 | /// destination index
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| 47 | /// that is less than the specified current index.
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| 48 | /// </summary>
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| 49 | [PushExpression(StackType.Code, "CODE.DO*RANGE")]
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| 50 | public class CodeDoRangeExpression : DoRangeExpression {
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| 51 | public CodeDoRangeExpression() { }
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| 52 |
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| 53 | public CodeDoRangeExpression(LoopState state) : base(state) { }
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[14744] | 54 | public override bool Eval(IPushInterpreter interpreter) {
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| 55 | return this.Eval(interpreter, interpreter.CodeStack);
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[14727] | 56 | }
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| 57 |
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| 58 | protected override LoopExpression Clone(LoopState state) {
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| 59 | return new CodeDoRangeExpression(state);
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| 60 | }
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| 61 | }
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| 62 |
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| 63 | /// <summary>
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| 64 | /// An iteration instruction that executes the top item on the EXEC stack a number of times that depends on the top two
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| 65 | /// integers,
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| 66 | /// while also pushing the loop counter onto the INTEGER stack for possible access during the execution of the body of
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| 67 | /// the loop.
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| 68 | /// This is similar to CODE.DO*COUNT except that it takes its code argument from the EXEC stack. The top integer is the
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| 69 | /// "destination index" and the second integer is the "current index." First the code and the integer arguments are
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| 70 | /// saved locally
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| 71 | /// and popped. Then the integers are compared. If the integers are equal then the current index is pushed onto the
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| 72 | /// INTEGER stack
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| 73 | /// and the code (which is the "body" of the loop) is pushed onto the EXEC stack for subsequent execution. If the
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| 74 | /// integers are not
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| 75 | /// equal then the current index will still be pushed onto the INTEGER stack but two items will be pushed onto the EXEC
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| 76 | /// stack
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| 77 | /// -- first a recursive call to EXEC.DO*RANGE (with the same code and destination index, but with a current index that
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| 78 | /// has been
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| 79 | /// either incremented or decremented by 1 to be closer to the destination index) and then the body code. Note that the
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| 80 | /// range is
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| 81 | /// inclusive of both endpoints; a call with integer arguments 3 and 5 will cause its body to be executed 3 times, with
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| 82 | /// the loop
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| 83 | /// counter having the values 3, 4, and 5. Note also that one can specify a loop that "counts down" by providing a
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| 84 | /// destination
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| 85 | /// index that is less than the specified current index.
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| 86 | /// </summary>
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| 87 | [PushExpression(StackType.Exec, "EXEC.DO*RANGE")]
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| 88 | public class ExecDoRangeExpression : DoRangeExpression {
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| 89 | public ExecDoRangeExpression() { }
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| 90 |
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| 91 | public ExecDoRangeExpression(LoopState state) : base(state) { }
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[14744] | 92 | public override bool Eval(IPushInterpreter interpreter) {
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| 93 | return this.Eval(interpreter, interpreter.ExecStack);
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[14727] | 94 | }
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| 95 | protected override LoopExpression Clone(LoopState state) {
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| 96 | return new ExecDoRangeExpression(state);
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| 97 | }
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| 98 | }
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| 99 | } |
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