Make LuaStack::Load return special codes for 'slash command', 'white space', and 'truncated lua'

Source/Integration/LuaCall.cpp

@@ -205,25 +205,21 @@ FString UlxLuaCallLibrary::AllFunctionsWithPrefix(const TCHAR *Prefix)
 void UlxLuaCallLibrary::ValidateLuaExpr(
     ElxLuaSyntaxCheck &Status, FString &ErrorMessage, UObject *context, const FString &Code)
 {
-    if (Code.StartsWith(TEXT("/")))
-    {
-        ErrorMessage = "SlashCommand";
-        Status = ElxLuaSyntaxCheck::SlashCommand;
-        return;
-    }
-    if (Code.TrimStart().IsEmpty())
-    {
-        ErrorMessage = "";
-        Status = ElxLuaSyntaxCheck::Whitespace;
-        return;
-    }
     ALuprexGameModeBase *mode = ALuprexGameModeBase::FromContext(context);
     ErrorMessage = mode->ValidateLuaExpr(Code);
     if (ErrorMessage.IsEmpty())
     {
         Status = ElxLuaSyntaxCheck::ValidLua;
     }
-    else if (ErrorMessage.Contains(TEXT("<eof>")))
+    else if (ErrorMessage == TEXT("slash command"))
+    {
+        Status = ElxLuaSyntaxCheck::SlashCommand;
+    }
+    else if (ErrorMessage == TEXT("white space"))
+    {
+        Status = ElxLuaSyntaxCheck::Whitespace;
+    }
+    else if (ErrorMessage == TEXT("truncated lua"))
     {
         Status = ElxLuaSyntaxCheck::TruncatedLua;
     }

luprex/cpp/core/luastack.cpp

@@ -333,6 +333,17 @@ eng::string LuaCoreStack::load(LuaSlot result, std::string_view code, std::strin
         code = expanded;
     }
 
+    if (sv::has_prefix(code, "/"))
+    {
+        set(result, "slash command");
+        return "slash command";
+    }
+    if (sv::is_whitespace(code))
+    {
+        set(result, "white space");
+        return "white space";
+    }
+
     eng::string fullcontext = eng::string("=") + eng::string(context);
     luaL_loadbuffer(L_, code.data(), code.size(), fullcontext.c_str());
     int type = lua_type(L_, -1);
@@ -346,6 +357,10 @@ eng::string LuaCoreStack::load(LuaSlot result, std::string_view code, std::strin
         const char *str = lua_tolstring(L_, -1, &len);
         eng::string message(str, len);
         lua_pop(L_, 1);
+        if (sv::has_suffix(message, "near <eof>"))
+        {
+            message = "truncated lua";
+        }
         if (message.empty()) message = "unknown compiler error";
         set(result, message);
         return message;

luprex/cpp/core/util.cpp

@@ -199,6 +199,15 @@ bool is_lua_comment(string_view s) {
     return s.substr(start, 2) == "--";
 }
 
+bool is_whitespace(string_view s) {
+    for (int i = 0; i < int(s.size()); i++) {
+        if (!ascii_isspace(s[i])) {
+            return false;
+        }
+    }
+    return true;
+}
+
 string_view read_to_sep(string_view &source, char sep) {
     size_t pos = source.find(sep);
     string_view result;

luprex/cpp/core/util.hpp

@@ -110,6 +110,9 @@ bool is_lua_classname(string_view s);
 // Return true if the line of code is a lua comment.
 bool is_lua_comment(string_view s);
 
+// Return true if the line is entirely whitespace.
+bool is_whitespace(string_view s);
+
 // Return the first character, but if the view is empty,
 // return zero.
 inline char zfront(string_view &s) {