Make tangible.find use center={x,y,z} instead of centerx= etc

luprex/cpp/core/util.cpp

@@ -2,7 +2,7 @@
 #include "wrap-vector.hpp"
 #include "util.hpp"
 #include "fast-float.hpp"
-
+#include "luastack.hpp"
 
 #include <algorithm>
 #include <sys/types.h>
@@ -178,7 +178,14 @@ int common_prefix_length(string_view a, string_view b) {
 }
 
 bool is_lua_id(string_view str) {
-    return LuaCoreStack::valididentifier(str);
+    if (str.size() == 0) return false;
+    char c=str[0];
+    if ((!ascii_isalpha(c)) && (c!='_')) return false;
+    for (int i = 1; i < int(str.size()); i++) {
+        char c = str[i];
+        if ((!ascii_isalnum(c)) && (c!='_')) return false;
+    }
+    return true;
 }
 
 bool is_lua_comment(string_view s) {