Enum Row 

pub enum Row {
    Empty,
    Var(RowVarRef),
    Cons(String, Box<MonoType>, Box<Row>),
}

An extensible record row: a sequence of label : type bindings ending either in Empty (a closed record — exactly these labels and no others) or in Var (an open record — at least these labels, plus whatever the row variable’s eventual binding adds).

Deviation from v0.0.6: its RecordType (types.cppo.ml:319) is always closed; the only record polymorphism is indirect, via a plain type variable carrying a RecordKind (a label-typed lower bound) that unifies against a closed RecordType when the kind’s labels are a subset of the record’s (typechecker.ml:480-500, Assoc.domain_included) — which cannot express an open record type standing on its own (only a variable can be “open”). Giving rows their own recursive type former (Row::Cons/Var/Empty, Rémy-style row polymorphism) is strictly more general and lets unify do genuine label-subsumption with a remainder row variable (unify::row_extract). Kind::Record is kept for the one case v0.0.6 also has it for: a variable not yet known to be a record at all.

See MonoType for what the #[subast] list means. As with MonoType::Var, RowVarRef is not listed and a row variable is a leaf.

Variants

Empty

Var(RowVarRef)

Cons(String, Box<MonoType>, Box<Row>)

Implementations

impl Row

pub fn visit<__T>(&self, visitor: impl IntoVisitor<__T>) -> &Self

Visit self with any Visit, returning self to chain.

impl Row

pub fn visit_mut<__T>(&mut self, visitor: impl IntoVisitorMut<__T>) -> &mut Self

Visit self with any VisitMut, returning self to chain.

Trait Implementations

impl Ast for Row

impl Clone for Row

fn clone(&self) -> Row

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Row

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

Formats the value using the given formatter.

impl Display for Row

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

Formats the value using the given formatter.

impl<__F: FnMut(&Row)> IntoHook<Row> for __F

fn into_hook(self) -> impl Hook

impl<__F: FnMut(&mut Row)> IntoHookMut<Row> for __F

fn into_hook_mut(self) -> impl HookMut

impl<__F: FnMut(&Row)> IntoVisitor<Row> for __F

fn into_visitor(self) -> impl Visit

impl<__F: FnMut(&mut Row)> IntoVisitorMut<Row> for __F

fn into_visitor_mut(self) -> impl VisitMut

impl Repeater<0> for Row

type Type = Box<Row>

The leaked type, valid in the referrer’s context via <T as Repeater<INDEX>>::Type.

impl Repeater<1> for Row

type Type = String

The leaked type, valid in the referrer’s context via <T as Repeater<INDEX>>::Type.

impl Repeater<2> for Row

type Type = Box<MonoType>

The leaked type, valid in the referrer’s context via <T as Repeater<INDEX>>::Type.

impl Repeater<3> for Row

type Type = RowVarRef

The leaked type, valid in the referrer’s context via <T as Repeater<INDEX>>::Type.