let bindings type inference integers and floats strings and chars tuples records variants polymorphic variants unit physical vs structural equality

function definitions anonymous functions currying partial application labeled arguments optional arguments recursive functions mutual recursion pipeline operator higher-order functions

match expressions function shorthand guards or-patterns as-patterns nested patterns record patterns list patterns variant patterns exhaustiveness

lists List.map List.fold_left List.filter arrays array mutation sequences maps sets hashtables

type aliases parameterized types recursive types GADTs private types abstract types phantom types locally abstract types first-class modules existential packaging

module definitions module signatures module type functors include open local open module aliases nested modules generative functors

option result exceptions try with raise references mutable record fields lazy values effect handlers continuations

print_endline Printf.printf file input file output Sys.argv Unix environment JSON pattern Dune test structure assertions resource cleanup