These old papers might pique your interest Shape in Computing [https://dl.acm.org/doi/10.1145/234528.234749 https://dl.acm.org/doi/10.1145/234528.234749 ] A

These old papers might pique your interest Shape in Computing [https://dl.acm.org/doi/10.1145/234528.234749 https://dl.acm.org/doi/10.1145/234528.234749 ] A Semantics for Shape [https://www.sciencedirect.com/science/article/pii/0167642395000151 https://www.sciencedirect.com/science/article/pii/0167642395... ] https://www.semanticscholar.org/paper/The-FISh-language-definition-Jay/cc414b98ba5e65f47c18470a5739195f4a63a209 https://www.semanticscholar.org/paper/The-FISh-language-defi... https://link.springer.com/article/10.1007/s100090050037 https://link.springer.com/article/10.1007/s100090050037 The page for FiSH used to be online. I cant find it now.