Enum PrologTerm 

pub enum PrologTerm {
    Atom(String),
    Integer(i64),
    Float(f64),
    Variable(String),
    Compound(String, Vec<PrologTerm>),
    List(Vec<PrologTerm>, Option<Box<PrologTerm>>),
    Nil,
    DcgPhrase(Box<PrologTerm>, Box<PrologTerm>),
    Op(String, Box<PrologTerm>, Box<PrologTerm>),
    PrefixOp(String, Box<PrologTerm>),
    Cut,
    Anon,
}

A Prolog term (the universal data structure in Prolog).

Variants

Atom(String)

An atom: lowercase identifier or quoted string, e.g. foo, 'hello world'

Integer(i64)

An integer literal, e.g. 42, -7

Float(f64)

A float literal, e.g. 3.14

Variable(String)

A variable: uppercase-starting or _-prefixed name, e.g. X, _Acc

Compound(String, Vec<PrologTerm>)

A compound term: functor(arg1, arg2, ...), e.g. f(a, b), +(1, 2)

List(Vec<PrologTerm>, Option<Box<PrologTerm>>)

A proper or partial list: [H|T], [1,2,3]

Nil

The empty list []

DcgPhrase(Box<PrologTerm>, Box<PrologTerm>)

A DCG rule term: phrase(Rule, List)

Op(String, Box<PrologTerm>, Box<PrologTerm>)

An operator term written in infix notation, e.g. X is Y + 1

PrefixOp(String, Box<PrologTerm>)

A prefix operator term, e.g. \+(X)

Cut

A cut !

Anon

Anonymous variable _

Implementations

impl PrologTerm

pub fn atom(s: impl Into<String>) -> Self

Create an atom.

pub fn var(s: impl Into<String>) -> Self

Create a variable.

pub fn compound(functor: impl Into<String>, args: Vec<PrologTerm>) -> Self

Create a compound term.

pub fn list(elems: Vec<PrologTerm>) -> Self

Create a proper list from elements.

pub fn list_partial(elems: Vec<PrologTerm>, tail: PrologTerm) -> Self

Create a partial list [H1,H2,...|T].

pub fn op(op: impl Into<String>, lhs: PrologTerm, rhs: PrologTerm) -> Self

Create an infix operator term.

pub fn prefix_op(op: impl Into<String>, arg: PrologTerm) -> Self

Create a prefix operator term.

pub fn functor_arity(&self) -> usize

Arity of this term as a functor (0 for atoms, variables, etc.)

Trait Implementations

impl Clone for PrologTerm

fn clone(&self) -> PrologTerm

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PrologTerm

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

Formats the value using the given formatter.

impl Display for PrologTerm

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

Formats the value using the given formatter.

impl PartialEq for PrologTerm

fn eq(&self, other: &PrologTerm) -> 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 StructuralPartialEq for PrologTerm