[−][src]Trait adapton::catalog::collections::ListElim

pub trait ListElim<X>: Debug + Clone + Hash + PartialEq + Eq {
    fn elim<Res, NilF, ConsF, NameF>(
        _: &Self, 
        _: NilF, 
        _: ConsF, 
        _: NameF
    ) -> Res
    where
        NilF: FnOnce(&Self) -> Res,
        ConsF: FnOnce(&X, &Self) -> Res,
        NameF: FnOnce(&Name, &Self) -> Res;

    fn elim_arg<Arg, Res, NilF, ConsF, NameF>(
        _: Self, 
        _: Arg, 
        _: NilF, 
        _: ConsF, 
        _: NameF
    ) -> Res
    where
        NilF: FnOnce(Self, Arg) -> Res,
        ConsF: FnOnce(X, Self, Arg) -> Res,
        NameF: FnOnce(Name, Self, Arg) -> Res;

    fn is_empty(list: &Self) -> bool { ... }

    fn is_name(list: &Self) -> bool { ... }
}

Types that can be pattern-matched like a list of X are ListElim<X>. We consider iterators to be a similar (nearly analogous) trait. The key distinction here are that list elimination is a pattern-match used with (pure) recursion, as opposed to an imperative for-loop, as is typical of iteration; further, lists in Adapton contain data (of type X) and names (of type Name).

Required methods

fn elim<Res, NilF, ConsF, NameF>(_: &Self, _: NilF, _: ConsF, _: NameF) -> Res where
    NilF: FnOnce(&Self) -> Res,
    ConsF: FnOnce(&X, &Self) -> Res,
    NameF: FnOnce(&Name, &Self) -> Res, 

Eliminate a list with the given functions (for the pattern match arms) that handle the nil, cons and name cases. Eliminates the art case internally, by forcing the art and eliminating the resulting list with the given handler functions; forces multiple art cases, if need be.

fn elim_arg<Arg, Res, NilF, ConsF, NameF>(
    _: Self,
    _: Arg,
    _: NilF,
    _: ConsF,
    _: NameF
) -> Res where
    NilF: FnOnce(Self, Arg) -> Res,
    ConsF: FnOnce(X, Self, Arg) -> Res,
    NameF: FnOnce(Name, Self, Arg) -> Res, 

Like elim, except that the functions are given an additional argument. This variant is needed due to the move semantics of Rust. The argument is moved into the body of the activated handler function when it is applied.

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Provided methods

fn is_empty(list: &Self) -> bool

Tests if the list contains any cons cells. Derived from elim.

fn is_name(list: &Self) -> bool

Tests if the head of the list consists of a name constructor. Derived from elim.

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Implementors

impl<X: 'static + Debug + Hash + PartialEq + Eq + Clone> ListElim<X> for List<X>[src]

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