Prolog? Prolog uses backtracking as the principal control flow paradigm and allows user-defined languages/DSLs by defining tokens, their associativity and prec

Prolog? Prolog uses backtracking as the principal control flow paradigm and allows user-defined languages/DSLs by defining tokens, their associativity and precedence in operator-precedence parsing, where tokens are character sequences that are either all graphic characters or all letters/digits. Example from the book Adventures in Prolog as returned by a cursory Google search: ? op(35, xfx, is_in) banana is_in room(kitchen).