Enum Fixity 

#[repr(u8)]
pub enum Fixity {
    Fun = 0,
    Prefix = 1,
    Infix = 2,
    Postfix = 3,
}

Defines the syntactic position (fixity) of an operator.

Operators in Prolog-like syntax can appear in different structural positions depending on their form. The Fixity enum captures these roles and is used to categorize operators within the parser and operator definition tables.

Variants

• [Fun]: A functional (non-operator) form, e.g., f(x, y).
• [Prefix]: A prefix operator appearing before its operand, e.g., -x.
• [Infix]: An infix operator appearing between two operands, e.g., x + y.
• [Postfix]: A postfix operator appearing after its operand, e.g., x!.

Variants

Fun = 0

Functional (non-operator) position, e.g. f(x).

Prefix = 1

Prefix operator, appearing before its operand, e.g. -x.

Infix = 2

Infix operator, appearing between operands, e.g. x + y.

Postfix = 3

Postfix operator, appearing after its operand, e.g., x!.

Implementations

impl Fixity

pub const COUNT: usize = 4usize

The total number of fixity variants.

pub const STRS: &[&str]

String representations of each fixity variant, in declaration order.

Trait Implementations

impl Clone for Fixity

fn clone(&self) -> Fixity

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Fixity

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

Formats the value using the given formatter.

impl Display for Fixity

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

Formats the fixity as its canonical lowercase name.

impl From<Fixity> for String

fn from(f: Fixity) -> Self

Converts a Fixity into its lowercase string representation.

impl From<Fixity> for usize

fn from(f: Fixity) -> Self

Converts a Fixity value into its numeric index (0–3).

impl FromStr for Fixity

Parses a string into a Fixity variant.

Accepts canonical lowercase names: "fun", "prefix", "infix", or "postfix". Returns a ParseFixityError if the input string does not match any known fixity.

type Err = ParseFixityError

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Index<Fixity> for OperDefTab

fn index(&self, i: Fixity) -> &Self::Output

Indexes the table by Fixity, returning the corresponding definition.

Panics

Panics if the fixity discriminant is out of range (should never occur).

type Output = Option<OperDef>

The returned type after indexing.

impl IndexMut<Fixity> for OperDefTab

fn index_mut(&mut self, i: Fixity) -> &mut Self::Output

Mutable indexing by Fixity, allowing modification of the definition.

Panics

Panics if the fixity discriminant is out of range (should never occur).

impl PartialEq for Fixity

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl TryFrom<&str> for Fixity

type Error = ParseFixityError

The type returned in the event of a conversion error.

fn try_from(s: &str) -> Result<Self, Self::Error>

Performs the conversion.

impl TryFrom<SmartString<LazyCompact>> for Fixity

type Error = ParseFixityError

The type returned in the event of a conversion error.

fn try_from(s: String) -> Result<Self, Self::Error>

Performs the conversion.

impl Copy for Fixity

impl Eq for Fixity

impl StructuralPartialEq for Fixity