properly handling errors in module loaders in package library (avoid lingering entry in "loading" table); throwing an error in robot library if its not a robot; automatically trying to load modules in interpreter (somewhat experimental)

assets/opencomputers/lua/rom/bin/lua.lua

@@ -3,9 +3,16 @@ local package = require("package")
 local term = require("term")
 local text = require("text")
 
+local function optrequire(...)
+  local success, module = pcall(require, ...)
+  if success then
+    return module
+  end
+end
+
 local history = {}
 local env = setmetatable({}, {__index = function(t, k)
-  return _ENV[k] or package.loaded[k]
+  return _ENV[k] or optrequire(k)
 end})
 
 component.gpu.setForeground(0xFFFFFF)

assets/opencomputers/lua/rom/lib/package.lua

@@ -74,12 +74,12 @@ table.insert(package.searchers, pathSearcher)
 
 function require(module)
   checkArg(1, module, "string")
-  if loaded[module] then
+  if loaded[module] ~= nil then
     return loaded[module]
   elseif not loading[module] then
     loading[module] = true
     local loader, value, errorMsg = nil, nil, {"module '" .. module .. "' not found:"}
-    for i=1, #package.searchers do
+    for i = 1, #package.searchers do
       local f, extra = package.searchers[i](module)
       if f and type(f) ~= "string" then
         loader = f
@@ -90,20 +90,23 @@ function require(module)
       end
     end
     if loader then
-      local result = loader(module, value)
+      local success, result = pcall(loader, module, value)
+      loading[module] = false
+      if not success then
+        error(result, 2)
+      end
       if result then
         loaded[module] = result
       elseif not loaded[module] then
         loaded[module] = true
       end
-      loading[module] = false
       return loaded[module]
     else
       loading[module] = false
-      error(table.concat(errorMsg, "\n"))
+      error(table.concat(errorMsg, "\n"), 2)
     end
   else
-    error("already loading: " .. module)
+    error("already loading: " .. module, 2)
   end
 end
 

assets/opencomputers/lua/rom/lib/robot.lua

@@ -3,7 +3,7 @@ local computer = require("computer")
 local sides = require("sides")
 
 if not computer.isRobot() then
-  return nil, "not a robot"
+  error("not a robot")
 end
 
 local robot = {}