std::optional

Optional(T) / T? is a language type, not a stdlib-defined enum. The compiler already provides the method-oriented combinator surface on optional values. std::optional exists as a stdlib namespace of free-function companions for those built-in methods.

Exported API#

module std::optional;

export fn is_some (T; value: T?) -> bool;
export fn is_none (T; value: T?) -> bool;
export fn map (T, U; value: T?, f: fn(T) -> U) -> U?;
export fn and_then (T, U; value: T?, f: fn(T) -> U?) -> U?;
export fn or_else (T; value: T?, f: fn() -> T?) -> T?;
export fn unwrap_or (T; value: T?, fallback: T) -> T;
export fn unwrap_or_else (T; value: T?, f: fn() -> T) -> T;

Notes#

• These functions forward to the built-in optional methods.
• The canonical semantics remain specified in optional.
• In Silk currently, higher-order generic calls may require explicit compile-time type arguments at the call site, for example std::optional::map(int, int; value, f).