This is a compile-time implementation of Sudoku where only correct Sudoku solutions are well-typed, relying only on features from C++ 98.
A Sudoku table can be declared using a series of nine row declarations as template parameters. See the end of the file for a few examples.
For fully evaluating the types (and therefore performing the validation), either type t from the table have to be typedef'ed or an object has to be instantiated.
It was inspired by this post on r/ProgrammerHumor, titled "Sudoku validity is a Total function":
