umx_compiler

commit ca13c7ec05c2e8aee27f5545d05abe993851ba57
parent 4469a343e5eb7af7b7ec8fb3a348630b159b60fc
Author: bsandro <email@bsandro.tech>
Date:   Fri, 24 Jun 2022 00:01:04 +0300

eval integer infix expressions: + - * /

Diffstat:
M
eval/eval.go
 | 
28
++++++++++++++++++++++++++++
M
eval/eval_test.go
 | 
4
++++

2 files changed, 32 insertions(+), 0 deletions(-)
diff --git a/eval/eval.go b/eval/eval.go
@@ -32,6 +32,10 @@ func Eval(node ast.Node) object.Object {
 	case *ast.PrefixExpression:
 		right := Eval(node.Right)
 		return evalPrefixExpression(node.Operator, right)
+	case *ast.InfixExpression:
+		left := Eval(node.Left)
+		right := Eval(node.Right)
+		return evalInfixExpression(node.Operator, left, right)
 	}
 	return nil
 }
@@ -75,3 +79,27 @@ func evalMinusPrefixOperatorExpression(right object.Object) object.Object {
 	value := right.(*object.Integer).Value
 	return &object.Integer{Value: -value}
 }
+
+func evalInfixExpression(operator string, left, right object.Object) object.Object {
+	if left.Type() == object.INTEGER_OBJ && right.Type() == object.INTEGER_OBJ {
+		return evalIntegerInfixExpression(operator, left, right)
+	}
+	return NULL
+}
+
+func evalIntegerInfixExpression(operator string, left, right object.Object) object.Object {
+	leftValue := left.(*object.Integer).Value
+	rightValue := right.(*object.Integer).Value
+	switch operator {
+	case "+":
+		return &object.Integer{Value: leftValue + rightValue}
+	case "-":
+		return &object.Integer{Value: leftValue - rightValue}
+	case "*":
+		return &object.Integer{Value: leftValue * rightValue}
+	case "/":
+		return &object.Integer{Value: leftValue / rightValue}
+	default:
+		return NULL
+	}
+}
diff --git a/eval/eval_test.go b/eval/eval_test.go
@@ -16,6 +16,10 @@ func TestEvalIntegerExpression(t *testing.T) {
 		{"-8", -8},
 		{"10", 10},
 		{"-256", -256},
+		{"1+2*3", 7},
+		{"10/5", 2},
+		{"3*3*3+10", 37},
+		{"(5+10*2+15/3)*2+-10", 50},
 	}
 	for _, tt := range tests {
 		evaluated := testEval(tt.input)