add more opcodes, preparing for HOF

1 files changed, 53 insertions, 0 deletions

diff --git a/vm.d b/vm.d
index 6ab2e96..75f6328 100644
--- a/vm.d
+++ b/vm.d
@@ -174,6 +174,11 @@ class VM {
         return value.type == ValueType.SEQ;
     }
 
+    bool isNil(Value value) {
+        return isList(value) &&
+                value.as.seq.length() == 0;
+    }
+
     bool isList(Value value) {
         return isSeq(value) && seqTypeOf(value) == SeqType.LIST;
     }
@@ -287,6 +292,45 @@ class VM {
 
             ubyte inst;
             switch (inst = this.readByte()) {
+                case OpCode.OP_IS_NIL:
+                    Value val = this.popA();
+                    this.pushA(makeBooleanValue(isNil(val)));
+                    break;
+                case OpCode.OP_DUPLICATE:
+                    this.pushA(this.peekA(0));
+                    break;
+                case OpCode.OP_DUPLICATE_2:
+                    this.pushA(this.peekA(1));
+                    this.pushA(this.peekA(1));
+                    break;
+                case OpCode.OP_ROTATE_N:
+                    int n = to!int(this.readByte());
+
+                    // pop the top of the stack
+                    Value top = this.popA();
+
+                    // pop the next n-1 values
+                    Value[] inner;
+                    for (int i = 0; i < n - 1; i++) {
+                        inner ~= this.popA();
+                    }
+
+                    // push the top
+                    this.pushA(top);
+
+                    // push the other values (preserve order)
+                    for (int i = n - 1; i >= 0; i--) {
+                        this.pushA(inner[i]);
+                    }
+                    break;
+                case OpCode.OP_ZERO:
+                    this.pushA(makeNumberValue(0));
+                    break;
+                case OpCode.OP_INCREMENT:
+                    Value val = this.popA();
+                    double num = asNumber(val);
+                    this.pushA(makeNumberValue(num + 1));
+                    break;
                 case OpCode.OP_DEF_GLOBAL:
                     Value name = this.current.func.chunk.constants[this.readByte()];
                     if (!isString(name)) {
@@ -340,6 +384,15 @@ class VM {
                     //bStack[bTop + slot - 1] = peekA(0);
                     this.popA();
                     break;
+                case OpCode.OP_LIST_N:
+                    Value lengthVal = this.popA();
+                    int length = to!int(asNumber(lengthVal));
+                    List lst = new List(length);
+                    for (int i = length - 1; i >= 0; i--) {
+                        lst.addItemAtIndex(this.popA(), i);
+                    }
+                    this.pushA(makeSeqValue(lst));
+                    break;
                 case OpCode.OP_LIST:
                     int length = to!int(this.readByte());
                     List lst = new List(length);