A general language feature would be fexprs, or call-by-name (which can be combined with call-by-value using call-by-push-value). In Kernel[1] for example, wher

A general language feature would be fexprs, or call-by-name (which can be combined with call-by-value using call-by-push-value). In Kernel[1] for example, where operatives are an improved fexpr. ($define! $if ($vau (condition if-true if-false) env ($cond ((eval condition env) (eval if-true env)) (#t (eval if-false env))))) $vau is similar to $lambda, except it doesn't implicitly evaluate its operands, and it implicitly receives it's caller's dynamic environment as a first class value which gets bound to env. $lambda is not actually a builtin in Kernel, but wrap is, which constructs an applicative by wrapping an operative. ($define! $lambda ($vau (args . body) env (wrap (eval (list* $vau args #ignore body) env)))) All functions have an underlying operative which can be extracted with unwrap. [1]:https://ftp.cs.wpi.edu/pub/techreports/pdf/05-07.pdf https://ftp.cs.wpi.edu/pub/techreports/pdf/05-07.pdf