private static GmState StepPrim(GmInstruction.Prim instruction, GmState state)
{
if (!PrimHandlers.TryGetValue(instruction.Type, out var handler))
{
throw new KeyNotFoundException(instruction.Type.ToString());
}
return(handler(state));
}
private static PrettyPrinter.Node ShowStack(GmState state) =>
Append(
Str("Stk ["),
Indent(Interleave(new PrettyPrinter.Node.Newline(), state.Stack.Select(addr => Append(
ShowAddr(addr),
Str(": "),
ShowNode(state, addr)
)))),
Str(" ]")
);
public IEnumerable <GmState> Evaluate(GmState state)
{
yield return(state);
while (!IsComplete(state))
{
state = Step(state);
yield return(state);
}
}
private static GmState StepUnwind(GmInstruction.Unwind _, GmState state)
{
var head = state.Stack.Peek();
var headNode = state.Heap[head];
return(headNode switch
{
GmNode.Number num => UnwindNum(num, state),
GmNode.Application ap => UnwindAp(ap, state),
GmNode.Global global => UnwindGlobal(global, state),
GmNode.Indirection ind => UnwindInd(ind, state),
_ => throw new ArgumentOutOfRangeException(nameof(headNode))
});
private static GmState Step(GmState state)
{
var(instruction, newState) = state.DequeueInstruction();
return(instruction switch
{
GmInstruction.PushGlobal pushGlobal => StepPushGlobal(pushGlobal, newState),
GmInstruction.PushInt pushInt => StepPushInt(pushInt, newState),
GmInstruction.MkAp mkAp => StepMkAp(mkAp, newState),
GmInstruction.Push push => StepPush(push, newState),
GmInstruction.Update update => StepUpdate(update, newState),
GmInstruction.Pop pop => StepPop(pop, newState),
GmInstruction.Slide slide => StepSlide(slide, newState),
GmInstruction.Alloc alloc => StepAlloc(alloc, newState),
GmInstruction.Unwind unwind => StepUnwind(unwind, newState),
GmInstruction.Eval eval => StepEval(eval, newState),
GmInstruction.Prim prim => StepPrim(prim, newState),
GmInstruction.Cond cond => StepCond(cond, newState),
_ => throw new ArgumentOutOfRangeException(nameof(instruction))
});
private static GmState BoxBool(bool value, GmState state)
{
return(state.AllocateAndPush(new GmNode.Number(value ? 1 : 0)));
}
private static int UnboxNum(int addr, GmState state)
{
return(((GmNode.Number)state.Heap[addr]).Value);
}
private static GmState BoxNum(int value, GmState state)
{
return(state.AllocateAndPush(new GmNode.Number(value)));
}
public static string Print(GmState state) => PrettyPrinter.Display(ShowState(state));
private static PrettyPrinter.Node ShowNode(GmState state, int addr) =>
state.Heap[addr] switch
{
private static PrettyPrinter.Node ShowState(GmState state) => Append(ShowStack(state), Newline());
private static bool IsComplete(GmState state)
{
return(state.Code.IsEmpty);
}