Enum DerivationRole 

pub enum DerivationRole {
    Matched,
    Differed,
    AtConstructor,
    Combine,
}

Which binding of a derivation a value is. The type each has is the one the chapter gives it, over Derivation::result and Position.

Variants

Matched

matched : R.

Differed

differed : Position -> Position -> R.

AtConstructor

atConstructor : Position -> R.

Combine

combine : R -> R -> R.

Implementations

impl DerivationRole

pub fn name(&self) -> &'static str

The name the binding is written under.

pub fn parameters(&self) -> usize

How many parameters the binding may be written with: the arguments the walk supplies it. A binding written with fewer is applied to the rest, and one written with more would need a function to be built from the walk, which canonical code has no form for.

Trait Implementations

impl Clone for DerivationRole

fn clone(&self) -> DerivationRole

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for DerivationRole

impl Debug for DerivationRole

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for DerivationRole

impl Hash for DerivationRole

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for DerivationRole

fn eq(&self, other: &DerivationRole) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for DerivationRole