From 62ed37ffdd0d6c892c3f359b9d837a011bace81f Mon Sep 17 00:00:00 2001
From: NPException <npexception42@gmail.com>
Date: Mon, 12 Nov 2018 22:29:01 +0100
Subject: [PATCH] fix read and eval of Lists, Sets, and Maps

---
 .../npecomplete/mc/testproject/lisp/Lisp.java | 40 +++++++++++++++++++
 .../mc/testproject/lisp/util/LispReader.java  | 11 ++++-
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/main/java/de/npecomplete/mc/testproject/lisp/Lisp.java b/src/main/java/de/npecomplete/mc/testproject/lisp/Lisp.java
index c1c40e0..26a04bc 100644
--- a/src/main/java/de/npecomplete/mc/testproject/lisp/Lisp.java
+++ b/src/main/java/de/npecomplete/mc/testproject/lisp/Lisp.java
@@ -1,7 +1,12 @@
 package de.npecomplete.mc.testproject.lisp;
 
 import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
 
 import de.npecomplete.mc.testproject.lisp.data.Sequence;
 import de.npecomplete.mc.testproject.lisp.data.Symbol;
@@ -95,6 +100,41 @@ public static Object eval(Object obj, Environment env) throws LispException {
 					+ "Call: " + call);
 		}
 
+		if (obj instanceof List) {
+			List<?> list = (List<?>) obj;
+			List<Object> result = new ArrayList<>();
+			for (Object o : list) {
+				result.add(eval(o, env));
+			}
+			return result;
+		}
+
+		if (obj instanceof Set) {
+			Set<?> set = (Set<?>) obj;
+			Set<Object> result = new HashSet<>(set.size() * 2);
+			for (Object o : set) {
+				Object key = eval(o, env);
+				if (result.contains(key)) {
+					throw new LispException("Set creation with duplicate key: " + key);
+				}
+				result.add(key);
+			}
+			return result;
+		}
+
+		if (obj instanceof Map) {
+			Map<?, ?> map = (Map<?, ?>) obj;
+			Map<Object, Object> result = new HashMap<>(map.size() * 2);
+			for (Entry e : map.entrySet()) {
+				Object key = eval(e.getKey(), env);
+				if (result.containsKey(key)) {
+					throw new LispException("Map creation with duplicate key: " + key);
+				}
+				result.put(key, eval(e.getValue(), env));
+			}
+			return result;
+		}
+
 		return obj;
 	}
 }
diff --git a/src/main/java/de/npecomplete/mc/testproject/lisp/util/LispReader.java b/src/main/java/de/npecomplete/mc/testproject/lisp/util/LispReader.java
index a4cf1a6..aee2804 100644
--- a/src/main/java/de/npecomplete/mc/testproject/lisp/util/LispReader.java
+++ b/src/main/java/de/npecomplete/mc/testproject/lisp/util/LispReader.java
@@ -9,6 +9,7 @@
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.Set;
 import java.util.stream.IntStream;
 
 import de.npecomplete.mc.testproject.lisp.LispException;
@@ -125,7 +126,9 @@ private static void buildCollection(Collection<Object> base, Token end, Iterator
 			if (value == end) {
 				return;
 			}
-			base.add(value);
+			if (!base.add(value) && base instanceof Set) {
+				throw new LispException("Duplicate key in set literal: " + value);
+			}
 		}
 		throw new LispException("Encountered end of data while reading a collection");
 	}
@@ -139,7 +142,11 @@ private static Object buildMap(Iterator<Token> it) {
 		Map<Object, Object> map = new HashMap<>(mapContents.size());
 		Iterator mapIt = mapContents.iterator();
 		while (mapIt.hasNext()) {
-			map.put(mapIt.next(), mapIt.next());
+			Object key = mapIt.next();
+			if (map.containsKey(key)) {
+				throw new LispException("Duplicate key in map literal: " + key);
+			}
+			map.put(key, mapIt.next());
 		}
 		return Collections.unmodifiableMap(map);
 	}