Null my old friend

compiler/compiler.go

@@ -134,16 +134,15 @@ func (c *Compiler) Compile(node ast.Node) error {
 			c.removeLastPop()
 		}
 
+		// Emit an `OnJump` with a bogus value
+		jumpPos := c.emit(code.OpJump, 9999)
+
+		afterConsequencePos := len(c.instructions)
+		c.changeOperand(jumpNotTruthyPos, afterConsequencePos)
+
 		if node.Alternative == nil {
-			afterConsequencePos := len(c.instructions)
-			c.changeOperand(jumpNotTruthyPos, afterConsequencePos)
+			c.emit(code.OpNull)
 		} else {
-			// Emit an `OnJump` with a bogus value
-			jumpPos := c.emit(code.OpJump, 9999)
-
-			afterConsequencePos := len(c.instructions)
-			c.changeOperand(jumpNotTruthyPos, afterConsequencePos)
-
 			err = c.Compile(node.Alternative)
 			if err != nil {
 				return err
@@ -152,12 +151,11 @@ func (c *Compiler) Compile(node ast.Node) error {
 			if c.lastInstructionIsPop() {
 				c.removeLastPop()
 			}
-
-			afterAlternativePos := len(c.instructions)
-			c.changeOperand(jumpPos, afterAlternativePos)
-
 		}
 
+		afterAlternativePos := len(c.instructions)
+		c.changeOperand(jumpPos, afterAlternativePos)
+
 	case *ast.BlockStatement:
 		for _, s := range node.Statements {
 			err := c.Compile(s)

compiler/compiler_test.go

@@ -182,17 +182,22 @@ func TestConditionals(t *testing.T) {
 			`,
 			expectedConstants: []interface{}{10, 3333},
 			expectedInstructions: []code.Instructions{
+				// 0000
 				code.Make(code.OpTrue),
 				// 0001
-				code.Make(code.OpJumpNotTruthy, 7),
+				code.Make(code.OpJumpNotTruthy, 10),
 				// 0004
 				code.Make(code.OpConstant, 0),
 				// 0007
-				code.Make(code.OpPop),
-				// 0008
-				code.Make(code.OpConstant, 1),
+				code.Make(code.OpJump, 11),
+				// 0010
+				code.Make(code.OpNull),
 				// 0011
 				code.Make(code.OpPop),
+				// 0012
+				code.Make(code.OpConstant, 1),
+				// 0015
+				code.Make(code.OpPop),
 			},
 		}, {
 			input: `