Enum fungi_lang::reduce::StepError

pub enum StepError {
    Halt(ExpTerm),
    Stuck(Stuck),
}

Cases for which step fails to reduce the program

Variants

Halt(ExpTerm)

Ordinary program termination

Though a “step error” (step cannot reduce the configuration), this outcome signals ordinary termination of the program. In particular, step cannot reduce a terminal expression in a configuration with an empty stack: there are no continuations to follow; these configurations have “halted” (terminated).

Stuck(Stuck)

Irreducible, ill-typed program configurations

All other errors (aside from an empty stack) are unexpected in a well-typed Fungi program, and correspond to reduction getting “stuck” in a state that is not well-typed.

Trait Implementations

impl Clone for StepError

fn clone(&self) -> StepError

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for StepError

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

Formats the value using the given formatter.

impl Hash for StepError

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<StepError> for StepError

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for StepError

impl StructuralEq for StepError

impl StructuralPartialEq for StepError