From 006836553321d5ce25ff4de4b5a71f19606fec37 Mon Sep 17 00:00:00 2001
From: Tom Willemse <tom@ryuslash.org>
Date: Wed, 11 Nov 2020 22:01:10 -0800
Subject: [PATCH] Throw a runtime error on division by zero

---
 src/com/craftinginterpreters/lox/Interpreter.java | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/com/craftinginterpreters/lox/Interpreter.java b/src/com/craftinginterpreters/lox/Interpreter.java
index 57e697c..1d87b87 100644
--- a/src/com/craftinginterpreters/lox/Interpreter.java
+++ b/src/com/craftinginterpreters/lox/Interpreter.java
@@ -119,9 +119,14 @@ class Interpreter implements Expr.Visitor<Object> {
                 }
 
                 throw new RuntimeError(expr.operator, "Operands must be two numbers or two strings.");
-            case SLASH:
+        case SLASH: {
                 checkNumberOperands(expr.operator, left, right);
-                return (double) left / (double) right;
+                double rhs = (double) right;
+                if (rhs == 0) {
+                    throw new RuntimeError(expr.operator, "Division by zero.");
+                }
+                return (double) left / rhs;
+        }
             case STAR:
                 checkNumberOperands(expr.operator, left, right);
                 return (double) left * (double) right;