FlightGear unterminated index fix

This came up again in FlightGear v2.12.1. The fix is probably very similar in version 2.10.0.3. The error:

Nasal runtime error: unterminated index (looking for ']')
  at C:/Program Files/FlightGear 2.12.1/data/Aircraft/777/Nasal/systems.nas, line 247 [????]
  called from: [...]/data/Aircraft/777/Nasal/systems.nas, line ???
  called from: [...]/data/Nasal/globals.nas, line ???

Option 1 - The Fix, "inline":

As always, the CDATA is only for HTML compliance, not part of the script.

<![CDATA[

# BEGIN SCRIPT FRAGMENT

    update_nd_plan_center : func {
        # find wpt lat, lon
		var index = me.nd_plan_wpt.getValue();
		if (num(index) == nil) return;   # Kwynn added this line - originally line 247
		if (int(index) != index) return; # Kwynn
		if (index < 0) return; # Kwynn
		var lat = getprop("autopilot/route-manager/route/wp[" ~ index ~ "]/latitude-deg");
		var lon = getprop("autopilot/route-manager/route/wp[" ~ index ~ "]/longitude-deg");

# END SCRIPT FRAGMENT
		
]]>

It is very likely that the only necessary line is the "if (index < 0) return;" but I wanted to post this ASAP without going through the variations.

Option 2 - replacement for systems.nas

Discussion

I only see this occasionally, but I saw it immediately when I tested v0.8.0 of my script. I can't conceive of the fix doing unintended harm, but I haven't flown much since I made the change.

Other Bug Fixes

History

Backlink to previous version.