From 35c288b03f8ae1d4accf764c900fd8d2668da2cf Mon Sep 17 00:00:00 2001
From: gnembon <gnembonmc@gmail.com>
Date: Mon, 8 Feb 2021 15:39:41 -0400
Subject: [PATCH] looping on nulls behaves like on empty lists.

---
 src/main/java/carpet/script/language/Loops.java | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/main/java/carpet/script/language/Loops.java b/src/main/java/carpet/script/language/Loops.java
index cfd1cbbd..4908a853 100644
--- a/src/main/java/carpet/script/language/Loops.java
+++ b/src/main/java/carpet/script/language/Loops.java
@@ -100,6 +100,7 @@ public class Loops {
         expression.addLazyFunction("map", 2, (c, t, lv) ->
         {
             Value rval= lv.get(0).evalValue(c, Context.NONE);
+            if (rval.isNull()) return ListValue.lazyEmpty();
             if (!(rval instanceof AbstractListValue))
                 throw new InternalExpressionException("First argument of 'map' function should be a list or iterator");
             Iterator<Value> iterator = ((AbstractListValue) rval).iterator();
@@ -145,6 +146,7 @@ public class Loops {
         expression.addLazyFunction("filter", 2, (c, t, lv) ->
         {
             Value rval= lv.get(0).evalValue(c, Context.NONE);
+            if (rval.isNull()) return ListValue.lazyEmpty();
             if (!(rval instanceof AbstractListValue))
                 throw new InternalExpressionException("First argument of 'filter' function should be a list or iterator");
             Iterator<Value> iterator = ((AbstractListValue) rval).iterator();
@@ -192,6 +194,7 @@ public class Loops {
         {
 
             Value rval= lv.get(0).evalValue(c, Context.NONE);
+            if (rval.isNull()) return LazyValue.NULL;
             if (!(rval instanceof AbstractListValue))
                 throw new InternalExpressionException("First argument of 'first' function should be a list or iterator");
             Iterator<Value> iterator = ((AbstractListValue) rval).iterator();
@@ -243,6 +246,7 @@ public class Loops {
         expression.addLazyFunction("all", 2, (c, t, lv) ->
         {
             Value rval= lv.get(0).evalValue(c, Context.NONE);
+            if (rval.isNull()) return LazyValue.TRUE;
             if (!(rval instanceof AbstractListValue))
                 throw new InternalExpressionException("First argument of 'all' function should be a list or iterator");
             Iterator<Value> iterator = ((AbstractListValue) rval).iterator();
@@ -307,6 +311,7 @@ public class Loops {
         expression.addLazyFunction("for", 2, (c, t, lv) ->
         {
             Value rval= lv.get(0).evalValue(c, Context.NONE);
+            if (rval.isNull()) return LazyValue.ZERO;
             if (!(rval instanceof AbstractListValue))
                 throw new InternalExpressionException("First argument of 'for' function should be a list or iterator");
             Iterator<Value> iterator = ((AbstractListValue) rval).iterator();
@@ -356,12 +361,13 @@ public class Loops {
         // returned value is substituted to the accumulator
         expression.addLazyFunction("reduce", 3, (c, t, lv) ->
         {
-            LazyValue expr = lv.get(1);
 
-            Value acc = lv.get(2).evalValue(c, Context.NONE);
             Value rval= lv.get(0).evalValue(c, Context.NONE);
+            if (rval.isNull()) return ListValue.lazyEmpty();
             if (!(rval instanceof AbstractListValue))
                 throw new InternalExpressionException("First argument of 'reduce' should be a list or iterator");
+            LazyValue expr = lv.get(1);
+            Value acc = lv.get(2).evalValue(c, Context.NONE);
             Iterator<Value> iterator = ((AbstractListValue) rval).iterator();
 
             if (!iterator.hasNext())