TypeTag

enum TypeTag : Enum<TypeTag>

TypeTag is an enumeration that corresponds with the basic type structure of Avail's type lattice. Even though the type lattice contains an infinite collection of infinitely long chains of types, some of which have an infinite number of direct ancestors and direct descendants, we're still able to extract a pragmatic tree of types from the lattice.

Since this restricted set of types form a tree, they're defined in such an order that all of a type's descendants follow it. Since this is recursively true, the types are effectively listed in depth-last order. The ordinals are assigned in the order of definition, but each type keeps track of the maximum ordinal of all of its descendants (which occupy a contiguous span of ordinals just after the type's ordinal). We can test if type A is a subtype of B by checking if a.ordinal ≥ b.ordinal and a.highOrdinal ≤ b.highOrdinal. For a proper subtype test, we turn the first condition into an inequality.

Author

Mark van Gulik

Parameters

instance

The most general instance of this TypeTag.

modifiers

The vararg list of Modifiers, which set flags or declare covariant and contravariant relationships.

Entries

BOTTOM_TYPE_TAG

BOTTOM_TYPE_TAG(TOP_TYPE_TAG, NIL_TAG, Unique { bottom })

META_TAG

META_TAG(ANY_TYPE_TAG, TOP_TYPE_TAG, Sup { instanceMeta(instanceMeta(Types.TOP.o)) })

FIBER_TYPE_TAG

FIBER_TYPE_TAG(NONTYPE_TYPE_TAG, FIBER_TAG, Sup { instanceMeta(mostGeneralFiberType()) }, Co("result") { resultType() })

RAW_FUNCTION_TYPE_TAG

RAW_FUNCTION_TYPE_TAG(NONTYPE_TYPE_TAG, RAW_FUNCTION_TAG, Sup { instanceMeta(mostGeneralCompiledCodeType()) }, Co("functionType") { functionType })

CONTINUATION_TYPE_TAG

CONTINUATION_TYPE_TAG(NONTYPE_TYPE_TAG, CONTINUATION_TAG, Sup { continuationMeta }, Contra("arguments") { functionType.argsTupleType }, Contra("result") { functionType.returnType })

TUPLE_TYPE_TAG

TUPLE_TYPE_TAG(NONTYPE_TYPE_TAG, TUPLE_TAG, Sup { instanceMeta(mostGeneralTupleType) }, Co("size", part = { fromInt(tupleSize) }) { sizeRange })

LITERAL_TOKEN_TYPE_TAG

LITERAL_TOKEN_TYPE_TAG(TOKEN_TYPE_TAG, LITERAL_TOKEN_TAG, Sup { instanceMeta(mostGeneralLiteralTokenType()) })

TOKEN_TYPE_TAG

TOKEN_TYPE_TAG(NONTYPE_TYPE_TAG, TOKEN_TAG, Sup { instanceMeta(Types.TOKEN.o) })

MAP_TYPE_TAG

MAP_TYPE_TAG(NONTYPE_TYPE_TAG, MAP_TAG, Sup { instanceMeta(mostGeneralMapType()) }, Co("size", part = { fromInt(mapSize) }) { sizeRange }, Co("key") { keyType }, Co("value") { valueType })

OBJECT_TYPE_TAG

OBJECT_TYPE_TAG(NONTYPE_TYPE_TAG, OBJECT_TAG, Sup { mostGeneralObjectMeta})

FUNCTION_TYPE_TAG

FUNCTION_TYPE_TAG(NONTYPE_TYPE_TAG, FUNCTION_TAG, Sup { instanceMeta(mostGeneralFunctionType()) }, Contra("arguments") { argsTupleType }, Co("return") { returnType })

VARIABLE_TYPE_TAG

VARIABLE_TYPE_TAG(NONTYPE_TYPE_TAG, VARIABLE_TAG, Sup { mostGeneralVariableMeta }, Co("read") { readType }, Contra("write") { writeType })

LIST_PHRASE_TYPE_TAG

LIST_PHRASE_TYPE_TAG(PHRASE_TYPE_TAG, LIST_PHRASE_TAG, Sup { instanceMeta(PhraseKind.LIST_PHRASE.mostGeneralType) })

PHRASE_TYPE_TAG

PHRASE_TYPE_TAG(NONTYPE_TYPE_TAG, PHRASE_TAG, Sup { instanceMeta(PhraseKind.PARSE_PHRASE.mostGeneralType) }, Co("yields") { phraseTypeExpressionType })

EXTENDED_INTEGER_TYPE_TAG

EXTENDED_INTEGER_TYPE_TAG(NUMBER_TYPE_TAG, EXTENDED_INTEGER_TAG, Sup { instanceMeta(extendedIntegers) })

NUMBER_TYPE_TAG

NUMBER_TYPE_TAG(NONTYPE_TYPE_TAG, NUMBER_TAG, Sup { instanceMeta(Types.NUMBER.o) })

POJO_TYPE_TAG

POJO_TYPE_TAG(NONTYPE_TYPE_TAG, POJO_TAG, Sup { instanceMeta(mostGeneralPojoType()) })

SET_TYPE_TAG

SET_TYPE_TAG(NONTYPE_TYPE_TAG, SET_TAG, Sup { instanceMeta(mostGeneralSetType()) }, Co("size", part = { fromInt(setSize) }) { sizeRange }, Co("element") { contentType })

FALSE_TYPE_TAG

FALSE_TYPE_TAG(BOOLEAN_TYPE_TAG, FALSE_TAG, Sup { instanceMeta(falseType) })

TRUE_TYPE_TAG

TRUE_TYPE_TAG(BOOLEAN_TYPE_TAG, TRUE_TAG, Sup { instanceMeta(trueType) })

BOOLEAN_TYPE_TAG

BOOLEAN_TYPE_TAG(ATOM_TYPE_TAG, BOOLEAN_TAG, Sup { instanceMeta(booleanType) })

ATOM_TYPE_TAG

ATOM_TYPE_TAG(NONTYPE_TYPE_TAG, ATOM_TAG, Sup { instanceMeta(Types.ATOM.o) })

NONTYPE_TYPE_TAG

NONTYPE_TYPE_TAG(ANY_TYPE_TAG, NONTYPE_TAG, Sup { instanceMeta(Types.NONTYPE.o) })

ANY_TYPE_TAG

ANY_TYPE_TAG(TOP_TYPE_TAG, null, Sup { instanceMeta(Types.ANY.o) })

TOP_TYPE_TAG

TOP_TYPE_TAG(TOP_TAG, TOP_TAG, Sup { instanceMeta(Types.TOP.o) })

VARIABLE_TAG

VARIABLE_TAG(NONTYPE_TAG, null, Sup { mostGeneralVariableType })

TUPLE_TAG

TUPLE_TAG(NONTYPE_TAG, null, Sup { mostGeneralTupleType })

LITERAL_TOKEN_TAG

LITERAL_TOKEN_TAG(TOKEN_TAG, null, Sup { mostGeneralLiteralTokenType() })

TOKEN_TAG

TOKEN_TAG(NONTYPE_TAG, null, Sup { Types.TOKEN.o })

SET_TAG

SET_TAG(NONTYPE_TAG, null, Sup { mostGeneralSetType() })

RAW_FUNCTION_TAG

RAW_FUNCTION_TAG(NONTYPE_TAG, null, Sup { mostGeneralCompiledCodeType() })

POJO_TAG

POJO_TAG(NONTYPE_TAG, null, Sup { mostGeneralPojoType() })

MACRO_SUBSTITUTION_PHRASE_TAG

MACRO_SUBSTITUTION_PHRASE_TAG(PHRASE_TAG, null, Sup { PhraseKind.MACRO_SUBSTITUTION_PHRASE.mostGeneralType })

EXPRESSION_AS_STATEMENT_PHRASE_TAG

EXPRESSION_AS_STATEMENT_PHRASE_TAG(STATEMENT_PHRASE_TAG, null, Sup { PhraseKind.EXPRESSION_AS_STATEMENT_PHRASE.mostGeneralType })

PRIMITIVE_FAILURE_REASON_PHRASE_TAG

PRIMITIVE_FAILURE_REASON_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.PRIMITIVE_FAILURE_REASON_PHRASE.mostGeneralType })

MODULE_CONSTANT_PHRASE_TAG

MODULE_CONSTANT_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.MODULE_CONSTANT_PHRASE.mostGeneralType })

MODULE_VARIABLE_PHRASE_TAG

MODULE_VARIABLE_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.MODULE_VARIABLE_PHRASE.mostGeneralType })

LOCAL_CONSTANT_PHRASE_TAG

LOCAL_CONSTANT_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.LOCAL_CONSTANT_PHRASE.mostGeneralType })

LOCAL_VARIABLE_PHRASE_TAG

LOCAL_VARIABLE_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.LOCAL_VARIABLE_PHRASE.mostGeneralType })

LABEL_PHRASE_TAG

LABEL_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.LABEL_PHRASE.mostGeneralType })

ARGUMENT_PHRASE_TAG

ARGUMENT_PHRASE_TAG(DECLARATION_PHRASE_TAG, null, Sup { PhraseKind.ARGUMENT_PHRASE.mostGeneralType })

DECLARATION_PHRASE_TAG

DECLARATION_PHRASE_TAG(STATEMENT_PHRASE_TAG, null, Sup { PhraseKind.STATEMENT_PHRASE.mostGeneralType })

FIRST_OF_SEQUENCE_PHRASE_TAG

FIRST_OF_SEQUENCE_PHRASE_TAG(STATEMENT_PHRASE_TAG, null, Sup { PhraseKind.FIRST_OF_SEQUENCE_PHRASE.mostGeneralType })

SEQUENCE_PHRASE_TAG

SEQUENCE_PHRASE_TAG(STATEMENT_PHRASE_TAG, null, Sup { PhraseKind.SEQUENCE_PHRASE.mostGeneralType })

STATEMENT_PHRASE_TAG

STATEMENT_PHRASE_TAG(PHRASE_TAG, null, Abstract, Sup { PhraseKind.STATEMENT_PHRASE.mostGeneralType })

SEQUENCE_AS_EXPRESSION_PHRASE_TAG

SEQUENCE_AS_EXPRESSION_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.SEQUENCE_AS_EXPRESSION_PHRASE.mostGeneralType })

VARIABLE_USE_PHRASE_TAG

VARIABLE_USE_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.VARIABLE_USE_PHRASE.mostGeneralType })

PERMUTED_LIST_PHRASE_TAG

PERMUTED_LIST_PHRASE_TAG(LIST_PHRASE_TAG, null, Sup { PhraseKind.PERMUTED_LIST_PHRASE.mostGeneralType })

LIST_PHRASE_TAG

LIST_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.LIST_PHRASE.mostGeneralType })

SEND_PHRASE_TAG

SEND_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.SEND_PHRASE.mostGeneralType })

SUPER_CAST_PHRASE_TAG

SUPER_CAST_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.SUPER_CAST_PHRASE.mostGeneralType })

REFERENCE_PHRASE_TAG

REFERENCE_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.REFERENCE_PHRASE.mostGeneralType })

LITERAL_PHRASE_TAG

LITERAL_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.LITERAL_PHRASE.mostGeneralType })

BLOCK_PHRASE_TAG

BLOCK_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.BLOCK_PHRASE.mostGeneralType })

ASSIGNMENT_PHRASE_TAG

ASSIGNMENT_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.ASSIGNMENT_PHRASE.mostGeneralType })

MARKER_PHRASE_TAG

MARKER_PHRASE_TAG(EXPRESSION_PHRASE_TAG, null, Sup { PhraseKind.MARKER_PHRASE.mostGeneralType })

EXPRESSION_PHRASE_TAG

EXPRESSION_PHRASE_TAG(PHRASE_TAG, null, Abstract, Sup { PhraseKind.EXPRESSION_PHRASE.mostGeneralType})

PHRASE_TAG

PHRASE_TAG(NONTYPE_TAG, null, Abstract, Sup { PhraseKind.PARSE_PHRASE.mostGeneralType })

PARSING_PLAN_IN_PROGRESS_TAG

PARSING_PLAN_IN_PROGRESS_TAG(NONTYPE_TAG, null, Sup {Types.PARSING_PLAN_IN_PROGRESS.o })

PARSING_PLAN_TAG

PARSING_PLAN_TAG(NONTYPE_TAG, null, Sup { Types.DEFINITION_PARSING_PLAN.o })

OBJECT_TAG

OBJECT_TAG(NONTYPE_TAG, null, Sup { mostGeneralObjectType })

DOUBLE_TAG

DOUBLE_TAG(NUMBER_TAG, null, Sup { Types.DOUBLE.o })

FLOAT_TAG

FLOAT_TAG(NUMBER_TAG, null, Sup { Types.FLOAT.o })

POSITIVE_INFINITY_TAG

POSITIVE_INFINITY_TAG(EXTENDED_INTEGER_TAG, null, Unique { positiveInfinity })

NEGATIVE_INFINITY_TAG

NEGATIVE_INFINITY_TAG(EXTENDED_INTEGER_TAG, null, Unique { negativeInfinity })

NATURAL_NUMBER_TAG

NATURAL_NUMBER_TAG(WHOLE_NUMBER_TAG, null, Sup { naturalNumbers })

WHOLE_NUMBER_TAG

WHOLE_NUMBER_TAG(INTEGER_TAG, null, Sup { wholeNumbers })

INTEGER_TAG

INTEGER_TAG(EXTENDED_INTEGER_TAG, null, Sup { integers })

EXTENDED_INTEGER_TAG

EXTENDED_INTEGER_TAG(NUMBER_TAG, null, Abstract, Sup { extendedIntegers })

NUMBER_TAG

NUMBER_TAG(NONTYPE_TAG, null, Abstract, Sup { Types.NUMBER.o })

MODULE_TAG

MODULE_TAG(NONTYPE_TAG, null, Sup { Types.MODULE.o })

METHOD_TAG

METHOD_TAG(NONTYPE_TAG, null, Sup { Types.METHOD.o })

MAP_TAG

MAP_TAG(NONTYPE_TAG, null, Sup { mostGeneralMapType() })

MACRO_TAG

MACRO_TAG(NONTYPE_TAG, null, Sup { Types.MACRO_DEFINITION.o })

LEXER_TAG

LEXER_TAG(NONTYPE_TAG, null, Sup { Types.LEXER.o })

FUNCTION_TAG

FUNCTION_TAG(NONTYPE_TAG, null, Sup { mostGeneralFunctionType() })

FIBER_TAG

FIBER_TAG(NONTYPE_TAG, null, Sup { mostGeneralFiberType() })

DEFINITION_TAG

DEFINITION_TAG(NONTYPE_TAG, null, Sup { Types.DEFINITION.o })

CONTINUATION_TAG

CONTINUATION_TAG(NONTYPE_TAG, null, Sup { mostGeneralContinuationType })

CHARACTER_TAG

CHARACTER_TAG(NONTYPE_TAG, null, Sup { Types.CHARACTER.o })

BUNDLE_TREE_TAG

BUNDLE_TREE_TAG(NONTYPE_TAG, null, Sup { Types.MESSAGE_BUNDLE_TREE.o })

BUNDLE_TAG

BUNDLE_TAG(NONTYPE_TAG, null, Sup { Types.MESSAGE_BUNDLE.o })

FALSE_TAG

FALSE_TAG(BOOLEAN_TAG, null, Unique { falseObject })

TRUE_TAG

TRUE_TAG(BOOLEAN_TAG, null, Unique { trueObject })

BOOLEAN_TAG

BOOLEAN_TAG(ATOM_TAG, null, Abstract, Sup { booleanType })

ATOM_TAG

ATOM_TAG(NONTYPE_TAG, null, Sup { Types.ATOM.o })

NONTYPE_TAG

NONTYPE_TAG(TOP_TAG, null, Sup { Types.NONTYPE.o })

NIL_TAG

NIL_TAG(TOP_TAG, null, Unique { nil }, Sup { Types.TOP.o })

TOP_TAG

TOP_TAG(null, null, Abstract, Sup { Types.TOP.o })

UNKNOWN_TAG

UNKNOWN_TAG(null, UNKNOWN_TAG, Abstract, Sup { Types.TOP.o })

Types

Companion

object Companion

Modifier

sealed class Modifier

Functions

commonAncestorWith

fun commonAncestorWith(other: TypeTag?): TypeTag

isSubtagOf

fun isSubtagOf(otherTag: TypeTag): Boolean

Properties

contravariants

val contravariants: MutableList<TypeTag.Modifier.Contra>

The array of Contravariant relationships defined during construction.

covariants

val covariants: MutableList<TypeTag.Modifier.Co>

The array of Covariant relationships defined during construction.

depth

val depth: Int

The number of ancestors of this TypeTag

highOrdinal

val highOrdinal: Int

The highest ordinal value of all of this TypeTag's descendants, including itself. The descendants' ordinals must start just after the current TypeTag's ordinal, and be contiguously numbered. Since the ordinals are assigned by the Enum mechanism, that means a TypeTag definition must be followed immediately by each of its children and their descendants, which is prefix tree order.

isAbstract

var isAbstract: Boolean = false

A flag set during initialization, indicating this TypeTag has no direct instances.

metaTag

val metaTag: TypeTag? = null

If object X has tag T, then X's type has tag T.metaTag.

name

val name: String

ordinal

val ordinal: Int

parent

val parent: TypeTag?

The parent of this TypeTag.

supremum

val supremum: A_Type

Every TypeTag has a (potentially infinite) collection of values that use that tag. After initialization, this property has the least upper bound A_Type that constrains all those values.

uniqueValue

val uniqueValue: AvailObject?

Some TypeTags occur in exactly one AvailObject. If so, this field will be initialized to a lambda that produces the value.