From f0a999cb2cf3e486b18ad222c6ba1b97ae73085d Mon Sep 17 00:00:00 2001
From: Stuart Buchanan <stuart_d_buchanan@yahoo.co.uk>
Date: Mon, 25 May 2020 19:47:50 +0100
Subject: [PATCH] Nasal library load order

Control the order in which fgdata/Nasal/*.nas files are loaded
on startup.

Previously all the files were loaded in order based on filename.
This was problematic for aaa.nas which might want to call
props.getNode(), and generally resolved by using
_setlistener("/sim/signals/nasal-dir-initialized")

This change allows us to configure a list of Nasal files that are
loaded first on startup - loadpriority.xml.
---
 Nasal/loadpriority.xml | 14 ++++++++++++++
 defaults.xml           |  1 +
 2 files changed, 15 insertions(+)
 create mode 100644 Nasal/loadpriority.xml

diff --git a/Nasal/loadpriority.xml b/Nasal/loadpriority.xml
new file mode 100644
index 000000000..85e5618c9
--- /dev/null
+++ b/Nasal/loadpriority.xml
@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<!--
+ Core Nasal module load priority list.
+ The files listed below will be loaded in order before any other files in the
+ Nasal directory.  This is to avoid dependency problems that would otherwise
+ occur if aaaa.nas relied on props.nas
+-->
+<PropertyList>
+  <file n="0">props.nas</file>
+  <file n="1">globals.nas</file>
+  <file n="2">math.nas</file>
+  <file n="3">string.nas</file>
+  <file n="3">io.nas</file>
+</PropertyList>
diff --git a/defaults.xml b/defaults.xml
index 1725c204c..7530c1f4f 100644
--- a/defaults.xml
+++ b/defaults.xml
@@ -19,6 +19,7 @@ Started September 2000 by David Megginson, david@megginson.com
     <session type="int" userarchive="y">0</session>
     <nasal-gc-threaded type="bool">true</nasal-gc-threaded>
     <nasal-gc-threaded-wait type="bool">false</nasal-gc-threaded-wait>
+    <nasal-load-priority include="Nasal/loadpriority.xml" />
     <paths>
       <screenshot-dir type="string" userarchive="y"/>
       <!-- defaults to current working dir -->