Enum lambda_calculus::reduction::Order

pub enum Order {
    Normal,
    CallByName,
    HeadSpine,
    HybridNormal,
    Applicative,
    CallByValue,
    HybridApplicative,
}

The evaluation order of β-reductions. The default is Normal.

They don't always yield the same result:

• The Normal, HybridNormal, Applicative and HybridApplicative orders reduce expressions to their normal forms
• The Applicative order will fail to fully reduce expressions containing functions without a normal form, e.g. the Y combinator (they will expand forever)
• The CallByName order reduces to weak head normal form
• The CallByValue order reduces to weak normal form
• The HeadSpine order reduces to head normal form

Variants

Normal

leftmost outermost

CallByName

leftmost outermost, but not inside abstractions

HeadSpine

leftmost outermost, but abstractions reduced only in head position

HybridNormal

a hybrid between HeadSpine and Normal

Applicative

leftmost innermost

CallByValue

leftmost innermost, but not inside abstractions

HybridApplicative

a hybrid between CallByValue and Applicative

Trait Implementations

impl Debug for Order

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl PartialEq for Order

fn eq(&self, __arg_0: &Order) -> 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 !=.

impl Display for Order

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

Formats the value using the given formatter.