Patterns
Patterns appear in match arms, let bindings, function parameters,
Active Patterns
F#-style user-defined patterns — total, partial, and parameterised.
Destructuring
Tuple, array, record, and nested destructuring in `let`, assignment, and parameters.
Comprehensions
List, stream, map, set, and generator comprehensions with unified clause syntax.
Quantifiers
forall and exists — universally and existentially quantified expressions.
Copatterns & Coinduction
Infinite data structures via observations — `cofix`, copattern bodies, and productivity.