Package net.hydromatic.morel.type

Interface Type

All Known Subinterfaces:

NamedType, RecordLikeType

All Known Implementing Classes:

BaseType, DataType, DummyType, FnType, ForallType, ListType, MultiType, ParameterizedType, PrimitiveType, ProgressiveRecordType, RecordType, TupleType, TypeVar

public interface Type

Type.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Type.Key	Structural identifier of a type.

Method Summary

Modifier and Type	Method	Description
<R> R	accept(TypeVisitor<R> typeVisitor)
default Type	arg(int i)	Returns the ith type parameter.
default boolean	canCallArgOf(Type type)	Whether this type is a function that can call an argument of given type.
Type	copy(TypeSystem typeSystem, UnaryOperator<Type> transform)	Copies this type, applying a given transform to component types, and returning the original type if the component types are unchanged.
default boolean	isCollection()	Whether this is a collection type (list or bag).
default boolean	isFinite()	Whether this type has a small, fixed set of instances.
default boolean	isProgressive()	Returns whether this type is progressive.
Type.Key	key()	Description of the type, e.g
default String	moniker()	Key of the type.
Op	op()	Type operator.
default boolean	specializes(Type type)	Whether this type is the same as, or a specialization of, a given type.
default Type	substitute(TypeSystem typeSystem, List<? extends Type> types)	Returns a copy of this type, specialized by substituting type parameters.
default @Nullable Map<Integer,Type>	unifyWith(Type type)

Method Details

key

Type.Key key()

Description of the type, e.g. "int", "int -> int", " NONE | SOME of 'a".

moniker

default String moniker()

Key of the type.

Often the same as key(), but an exception is datatype. For example, datatype "'a option" has moniker and name "option" and description "NONE | SOME of 'a".

Use the description if you are looking for a type that is structurally equivalent. Use the moniker to identify it when printing.

op

Op op()

Type operator.

arg

default Type arg(int i)

Returns the ith type parameter. Throws for types except ListType and DataType.

copy

Type copy(TypeSystem typeSystem,
 UnaryOperator<Type> transform)

Copies this type, applying a given transform to component types, and returning the original type if the component types are unchanged.

accept

<R> R accept(TypeVisitor<R> typeVisitor)

substitute

default Type substitute(TypeSystem typeSystem,
 List<? extends Type> types)

Returns a copy of this type, specialized by substituting type parameters.

isProgressive

default boolean isProgressive()

Returns whether this type is progressive.

Progressive types are records, but can have additional fields each time you look.

The "file" value is an example.

isFinite

default boolean isFinite()

Whether this type has a small, fixed set of instances. True for bool, data types on finite types.

isCollection

default boolean isCollection()

Whether this is a collection type (list or bag).

If a type is a collection type, arg(0) returns the element type.

canCallArgOf

default boolean canCallArgOf(Type type)

Whether this type is a function that can call an argument of given type.

For example:

• int is not a function and therefore results false for all argument types;
• bool -> int can call arguments of type bool and 'a but not int or ('a, 'b);
• forall 'a. 'a list -> bool can call arguments of type int list and string list list but not int option.

specializes

default boolean specializes(Type type)

Whether this type is the same as, or a specialization of, a given type.

For example, bool specializes bool and 'a but does not specialize int or ('a, 'b).

unifyWith

default @Nullable Map<Integer,Type> unifyWith(Type type)