Tangentially related: I must enjoyed Polygen (https://polygen.org https://polygen.org) that generates text using a BNF template and I have always wanted to cons

Tangentially related: I must enjoyed Polygen (https://polygen.org https://polygen.org) that generates text using a BNF template and I have always wanted to construct a template that generated viable templates (BNF of BNF?) but haven’t ever gotten around to it.