NullaryCallable

Requires a safe readonly zero-argument invocation with an exact result.

Sn is under heavy development. This reference includes the intended 1.0 design; features may be incomplete in the current compiler. Read the status →

Module std.iteration

import std.iteration;

Public declaration contracts and authored examples. A page can document several related symbols. Implementation bodies are excluded.

NullaryCallable

pub concept NullaryCallable<Self, R>

Requires a safe readonly zero-argument invocation with an exact result.

Concrete environments remain unboxed and keep their own capture/cleanup contracts. Generated closures receive canonical-package witness access only; user spellings do not gain private-method authority. No allocation, runtime dictionary or synchronization is introduced by concept satisfaction. Self: Concrete callback/environment representation. R: Exact return representation, including reference or void transport.

Documentation snapshot: October 24, 2026 About versions ↗