Module extract 

Types that hold exactly one value which can be extracted.

Extract is the inverse of Deferrable: where Deferrable constructs a value lazily from a thunk, Extract forces/extracts the inner value. For types whose brand implements Extract (e.g., ThunkBrand), extract(defer(|| x)) == x forms a round-trip. Note that Extract is a brand-level trait (implemented by ThunkBrand), while Deferrable is a value-level trait (implemented by concrete types like Thunk).

This trait is used by Free::evaluate to execute the effects in a Free monad.

Examples

use fp_library::{
	brands::*,
	functions::*,
	types::*,
};

let thunk = Thunk::new(|| 42);
assert_eq!(extract::<ThunkBrand, _>(thunk), 42);

Traits

Extract

A type containing exactly one extractable value, providing a natural transformation F ~> Id.

Functions

extract

Extracts the inner value.