The closest thing I’ve come across to this is Z (“Zed”) notation. It’s from the late 70s, quite influential and pretty easy to read with a bit of logic symbolism. The same designer (Jean-Raymond Abrial) and colleagues also made the B method which can also do program refinement. Several other “well-known” (relative to other formal methods) formal specification systems were influenced by Z, including possibly TLA+ as I’ve read somewhere (but cannot confirm). Z and B both have free tooling available online.