Enum avalog::Expr

pub enum Expr {
    Sym(Arc<String>),
    Rel(Box<Expr>, Box<Expr>),
    Ava(Box<Expr>, Box<Expr>),
    Inner(Box<Expr>),
    UniqAva(Box<Expr>),
    RoleOf(Box<Expr>, Box<Expr>),
    Eq(Box<Expr>, Box<Expr>),
    Neq(Box<Expr>, Box<Expr>),
    Has(Box<Expr>, Box<Expr>),
    App(Box<Expr>, Box<Expr>),
    AmbiguousRole(Box<Expr>, Box<Expr>, Box<Expr>),
    AmbiguousRel(Box<Expr>, Box<Expr>, Box<Expr>),
    Rule(Box<Expr>, Vec<Expr>),
    Ambiguity(bool),
    Tail,
    TailSym(Arc<String>),
    List(Vec<Expr>),
}

Represents an expression.

Variants

Sym(Arc<String>)

A symbol.

Rel(Box<Expr>, Box<Expr>)

A relation between two symbols.

Ava(Box<Expr>, Box<Expr>)

A 1-avatar of some expression.

Inner(Box<Expr>)

Unwraps 1-avatar.

UniqAva(Box<Expr>)

A 1-avatar q'(b) such that p(a) = q'(b).

RoleOf(Box<Expr>, Box<Expr>)

A role of expression.

Eq(Box<Expr>, Box<Expr>)

An equality, e.g. p(a) = b.

Neq(Box<Expr>, Box<Expr>)

An inequality, e.g. X != a.

Has(Box<Expr>, Box<Expr>)

A set membership relation, e.g. p(a) ∋ b.

App(Box<Expr>, Box<Expr>)

Apply an argument to a role, e.g. p(a).

AmbiguousRole(Box<Expr>, Box<Expr>, Box<Expr>)

There is an ambiguous role.

AmbiguousRel(Box<Expr>, Box<Expr>, Box<Expr>)

There is an ambiguous relation.

Rule(Box<Expr>, Vec<Expr>)

Defines a rule.

Ambiguity(bool)

Ambiguity summary.

This is true when some ambiguity is found, and false when no ambiguity is found.

Tail

Represents the tail of an argument list ...

TailSym(Arc<String>)

Represents the tail of an argument list bound a symbol ..x.

List(Vec<Expr>)

Represents a list.

Implementations

impl Expr

pub fn eval_lift(&self, eval: &Arc<String>, top: bool) -> Expr

Lifts apply with an eval role.

pub fn is_const(&self) -> bool

Returns true if expression contains no variables.

pub fn is_tail(&self) -> bool

Returns true if expression is a tail pattern.

pub fn arity(&self) -> usize

Returns the number of arguments in apply expression.

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.

impl Display for Expr

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

Formats the value using the given formatter.

impl Eq for Expr

impl From<&'static str> for Expr

fn from(val: &'static str) -> Expr

Performs the conversion.

impl Hash for Expr

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, 

Feeds a slice of this type into the given Hasher.

impl Ord for Expr

fn cmp(&self, other: &Expr) -> Ordering

This method returns an Ordering between self and other.

#[must_use]fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]fn clamp(self, min: Self, max: Self) -> Self

🔬 This is a nightly-only experimental API. (clamp)

Restrict a value to a certain interval.

impl PartialEq<Expr> for Expr

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

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

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

This method tests for !=.

impl PartialOrd<Expr> for Expr

fn partial_cmp(&self, other: &Expr) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Expr) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Expr) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Expr) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Expr) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralEq for Expr

impl StructuralPartialEq for Expr