variadic

Variadic describes constructs that can operate on a variable number of inputs. In mathematics and computer science, a variadic function or operator is defined to accept any finite number of arguments, rather than a fixed count. The term blends vari- “vary” with -adic, similar in spirit to other mathematical and programming terminology.

In programming, variadic functions are common across languages, though implementations differ. In C, a function can end with an ellipsis (...) to accept additional arguments beyond fixed parameters, with access via the va_list family of macros. C++ extends this idea with variadic templates, enabling type-safe expansion of parameter packs at compile time. Java supports variable arity methods by declaring a parameter of the form Type... name, allowing callers to pass any number of arguments of that type. Python uses *args to collect extra positional arguments and **kwargs for extra keyword arguments. JavaScript provides rest parameters (...) to gather remaining arguments into an array. Go also supports variadic functions using …T in the parameter list, where callers pass a sequence of values or a slice.

Common examples include printing or formatting routines such as C’s printf, Python’s print, or JavaScript’s console.log, which can handle arbitrary numbers of inputs. Variadic capabilities raise design considerations, including type safety, performance, and the complexity of handling heterogeneous argument lists. In languages built around static typing, variadic features are often complemented by templates, generics, or explicit slice/array conversions to preserve type safety. Beyond programming, variadic concepts appear in mathematics as functions defined on sequences of variable length.