diff --git a/error_handling.lua b/error_handling.lua
index f5bd10b..5cf54e5 100644
--- a/error_handling.lua
+++ b/error_handling.lua
@@ -3,16 +3,15 @@ local ok, to_lua = pcall(function()
   return require('moonscript.base').to_lua
 end)
 if not ok then
-  to_lua = nil
+  to_lua = function()
+    return nil
+  end
 end
-local moonscript_line_tables = setmetatable({ }, {
-  __index = function(self, filename)
-    if not (to_lua) then
-      return nil
-    end
-    local _, line_table = to_lua(FILE_CACHE[filename])
-    self[filename] = line_table
-    return line_table
+local MOON_SOURCE_MAP = setmetatable({ }, {
+  __index = function(self, file)
+    local _, line_table = to_lua(file)
+    self[file] = line_table or false
+    return line_table or false
   end
 })
 debug.getinfo = function(thread, f, what)
@@ -57,21 +56,6 @@ print_err_msg = function(error_message, stack_offset)
   end
   io.stderr:write(tostring(colored.red("ERROR:")) .. " " .. tostring(colored.bright(colored.red((error_message or "")))) .. "\n")
   io.stderr:write("stack traceback:\n")
-  ok, to_lua = pcall(function()
-    return require('moonscript.base').to_lua
-  end)
-  if not ok then
-    to_lua = function()
-      return nil
-    end
-  end
-  local LINE_TABLES = setmetatable({ }, {
-    __index = function(self, file)
-      local _, line_table = to_lua(file)
-      self[file] = line_table or false
-      return line_table or false
-    end
-  })
   local get_line
   get_line = function(file, line_no)
     local start = LINE_STARTS[file][line_no] or 1
@@ -116,7 +100,20 @@ print_err_msg = function(error_message, stack_offset)
           local file = FILE_CACHE[filename]:sub(tonumber(start), tonumber(stop))
           local err_line = get_line(file, calling_fn.currentline):sub(1, -2)
           local offending_statement = colored.bright(colored.red(err_line:match("^[ ]*(.*)")))
-          name = "action '" .. tostring(calling_fn.name) .. "'"
+          if calling_fn.name then
+            do
+              local tmp = calling_fn.name:match("^A_([a-zA-Z0-9_]*)$")
+              if tmp then
+                name = "action '" .. tostring(tmp:gsub("_", " "):gsub("x([0-9A-F][0-9A-F])", function(self)
+                  return string.char(tonumber(self, 16))
+                end)) .. "'"
+              else
+                name = "action '" .. tostring(calling_fn.name) .. "'"
+              end
+            end
+          else
+            name = "main chunk"
+          end
           line = colored.yellow(tostring(filename) .. ":" .. tostring(calling_fn.currentline) .. " in " .. tostring(name) .. "\n        " .. tostring(offending_statement))
         else
           local file
@@ -163,8 +160,8 @@ print_err_msg = function(error_message, stack_offset)
               end
             end
           end
-          if file and calling_fn.short_src:match(".moon$") and LINE_TABLES[file] then
-            local char = LINE_TABLES[file][calling_fn.currentline]
+          if file and calling_fn.short_src:match("%.moon$") and type(MOON_SOURCE_MAP[file]) == 'table' then
+            local char = MOON_SOURCE_MAP[file][calling_fn.currentline]
             line_num = 1
             for _ in file:sub(1, char):gmatch("\n") do
               line_num = line_num + 1
@@ -202,13 +199,8 @@ err_hand = function(error_message)
   print_err_msg(error_message)
   return os.exit(false, true)
 end
-local has_ldt, ldt = pcall(require, 'ldt')
 local safe_run
-if has_ldt then
-  safe_run = ldt.guard
-else
-  safe_run = function(fn)
-    return xpcall(fn, err_hand)
-  end
+safe_run = function(fn)
+  return xpcall(fn, err_hand)
 end
 return safe_run
diff --git a/error_handling.moon b/error_handling.moon
index 101c11e..d932b91 100644
--- a/error_handling.moon
+++ b/error_handling.moon
@@ -3,14 +3,12 @@ debug_getinfo = debug.getinfo
 export SOURCE_MAP
 
 ok, to_lua = pcall -> require('moonscript.base').to_lua
-if not ok then to_lua = nil
-moonscript_line_tables = setmetatable {}, {
-    __index: (filename)=>
-        return nil unless to_lua
-        _, line_table = to_lua(FILE_CACHE[filename])
-        self[filename] = line_table
-        return line_table
-}
+if not ok then to_lua = -> nil
+MOON_SOURCE_MAP = setmetatable {},
+    __index: (file)=>
+        _, line_table = to_lua(file)
+        self[file] = line_table or false
+        return line_table or false
 
 -- Make a better version of debug.getinfo that provides info about the original source
 -- where the error came from, even if that's in another language.
@@ -38,15 +36,6 @@ print_err_msg = (error_message, stack_offset=3)->
     io.stderr\write("#{colored.red "ERROR:"} #{colored.bright colored.red (error_message or "")}\n")
     io.stderr\write("stack traceback:\n")
 
-    -- TODO: properly print out the calling site of nomsu code, not just the *called* code
-    ok, to_lua = pcall -> require('moonscript.base').to_lua
-    if not ok then to_lua = -> nil
-    LINE_TABLES = setmetatable {},
-        __index: (file)=>
-            _, line_table = to_lua(file)
-            self[file] = line_table or false
-            return line_table or false
-
     get_line = (file, line_no)->
         start = LINE_STARTS[file][line_no] or 1
         stop = (LINE_STARTS[file][line_no+1] or 0) - 1
@@ -77,7 +66,11 @@ print_err_msg = (error_message, stack_offset=3)->
             err_line = get_line(file, calling_fn.currentline)\sub(1,-2)
             offending_statement = colored.bright(colored.red(err_line\match("^[ ]*(.*)")))
             -- TODO: get name properly
-            name = "action '#{calling_fn.name}'"
+            name = if calling_fn.name
+                if tmp = calling_fn.name\match("^A_([a-zA-Z0-9_]*)$")
+                    "action '#{tmp\gsub("_"," ")\gsub("x([0-9A-F][0-9A-F])", => string.char(tonumber(@, 16)))}'"
+                else "action '#{calling_fn.name}'"
+            else "main chunk"
             line = colored.yellow("#{filename}:#{calling_fn.currentline} in #{name}\n        #{offending_statement}")
         else
             ok, file = pcall ->FILE_CACHE[calling_fn.short_src]
@@ -105,8 +98,8 @@ print_err_msg = (error_message, stack_offset=3)->
                                 name = "upvalue '#{varname}'"
                                 if not varname\match("%(")
                                     break
-            if file and calling_fn.short_src\match(".moon$") and LINE_TABLES[file]
-                char = LINE_TABLES[file][calling_fn.currentline]
+            if file and calling_fn.short_src\match("%.moon$") and type(MOON_SOURCE_MAP[file]) == 'table'
+                char = MOON_SOURCE_MAP[file][calling_fn.currentline]
                 line_num = 1
                 for _ in file\sub(1,char)\gmatch("\n") do line_num += 1
                 line = colored.cyan("#{calling_fn.short_src}:#{line_num} in #{name or '?'}")
@@ -131,13 +124,7 @@ err_hand = (error_message)->
     print_err_msg error_message
     os.exit(false, true)
 
--- Note: xpcall has a slightly different API in Lua <=5.1 vs. >=5.2, but this works
--- for both APIs
-has_ldt, ldt = pcall(require,'ldt')
-safe_run = if has_ldt
-    ldt.guard
-else
-    (fn)->
-        xpcall(fn, err_hand)
+safe_run = (fn)->
+    xpcall(fn, err_hand)
 
 return safe_run
diff --git a/nomsu.lua b/nomsu.lua
index b500cfa..0b26ac0 100644
--- a/nomsu.lua
+++ b/nomsu.lua
@@ -187,4 +187,9 @@ run = function()
     end
   end
 end
-return run_safely(run)
+local has_ldt, ldt = pcall(require, 'ldt')
+if has_ldt then
+  return ldt.guard(run)
+else
+  return run_safely(run)
+end
diff --git a/nomsu.moon b/nomsu.moon
index 9dc256e..3aa2c60 100755
--- a/nomsu.moon
+++ b/nomsu.moon
@@ -157,4 +157,8 @@ run = ->
             elseif not ok
                 print_err_msg ret
 
-run_safely(run)
+has_ldt, ldt = pcall(require,'ldt')
+if has_ldt
+    ldt.guard(run)
+else
+    run_safely(run)
diff --git a/nomsu_compiler.lua b/nomsu_compiler.lua
index d093ff5..5c7fb91 100644
--- a/nomsu_compiler.lua
+++ b/nomsu_compiler.lua
@@ -501,7 +501,7 @@ do
       source = nil
     end
     local lua_string = tostring(lua)
-    local run_lua_fn, err = load(lua_string, nil and tostring(source or lua.source), "t", self)
+    local run_lua_fn, err = load(lua_string, tostring(source or lua.source), "t", self)
     if not run_lua_fn then
       local line_numbered_lua = concat((function()
         local _accum_0 = { }
diff --git a/nomsu_compiler.moon b/nomsu_compiler.moon
index 8226db4..4d7b4cf 100644
--- a/nomsu_compiler.moon
+++ b/nomsu_compiler.moon
@@ -339,7 +339,7 @@ with NomsuCompiler
 
     .run_lua = (lua, source=nil)=>
         lua_string = tostring(lua)
-        run_lua_fn, err = load(lua_string, nil and tostring(source or lua.source), "t", self)
+        run_lua_fn, err = load(lua_string, tostring(source or lua.source), "t", self)
         if not run_lua_fn
             line_numbered_lua = concat(
                 [format("%3d|%s",i,line) for i, line in ipairs get_lines\match(lua_string)],
diff --git a/parser.lua b/parser.lua
index 863e17e..a94418f 100644
--- a/parser.lua
+++ b/parser.lua
@@ -162,7 +162,8 @@ parse = function(nomsu_code, source)
       end
       errors = _accum_0
     end
-    error(table.concat(errors, "\n\n"), 0)
+    io.stderr:write("Errors occurred while parsing:\n\n", table.concat(errors, "\n\n"), '\n')
+    os.exit(1)
   end
   return tree
 end
diff --git a/parser.moon b/parser.moon
index 4de1fe2..a713e85 100644
--- a/parser.moon
+++ b/parser.moon
@@ -116,7 +116,8 @@ parse = (nomsu_code, source=nil)->
         keys = utils.keys(userdata.errors)
         table.sort(keys)
         errors = [userdata.errors[k] for k in *keys]
-        error(table.concat(errors, "\n\n"), 0)
+        io.stderr\write("Errors occurred while parsing:\n\n", table.concat(errors, "\n\n"), '\n')
+        os.exit(1)
     
     return tree