Simplify regex used in check_modname_prefix and other improvements.

Simplified the regex used, added comments and changed the error message
to contain the correct mod name.

diff --git a/builtin/game/register.lua b/builtin/game/register.lua
index 840ade1274a510e944838ab94e2eee54a61c77e3..00bb2327879f5094e541e6b3387aa947ae66c39b 100644 (file)
--- a/builtin/game/register.lua
+++ b/builtin/game/register.lua
@@ -51,20 +51,24 @@ local forbidden_item_names = {
 
 local function check_modname_prefix(name)
        if name:sub(1,1) == ":" then
-               -- Escape the modname prefix enforcement mechanism
+               -- If the name starts with a colon, we can skip the modname prefix
+               -- mechanism.
                return name:sub(2)
        else
-               -- Modname prefix enforcement
+               -- Enforce that the name starts with the correct mod name.
                local expected_prefix = core.get_current_modname() .. ":"
                if name:sub(1, #expected_prefix) ~= expected_prefix then
                        error("Name " .. name .. " does not follow naming conventions: " ..
-                               "\"modname:\" or \":\" prefix required")
+                               "\"" .. expected_prefix .. "\" or \":\" prefix required")
                end
+               
+               -- Enforce that the name only contains letters, numbers and underscores.
                local subname = name:sub(#expected_prefix+1)
-               if subname:find("[^abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_]") then
+               if subname:find("[^%w_]") then
                        error("Name " .. name .. " does not follow naming conventions: " ..
                                "contains unallowed characters")
                end
+               
                return name
        end
 end