Feature SysML

class Feature

Implementation of Feature defined in the KerML specification.

Specification:

A Feature is a Type that classifies relations between multiple things (in the universe). The domain of the relation is the intersection of the featuring_types of the Feature. (The domain of a Feature with no featuring_types is implicitly the most general Type Base::Anything from the Kernel Semantic Library.) The co-domain of the relation is the intersection of the types of the Feature.

In the simplest cases, the featuring_types and types are Classifiers and the Feature relates two things, one from the domain and one from the range. Examples include cars paired with wheels, people paired with other people, and cars paired with numbers representing the car length.

Since Features are Types, their featuring_types and types can be Features. In this case, the Feature effectively classifies relations between relations, which can be interpreted as the sequence of things related by the domain Feature concatenated with the sequence of things related by the co-domain Feature.

The values of a Feature for a given instance of its domain are all the instances of its co-domain that are related to that domain instance by the Feature. The values of a Feature with chaining_features are the same as values of the last Feature in the chain, which can be found by starting with values of the first Feature, then using those values as domain instances to obtain values of the second Feature, and so on, to values of the last Feature.

For language description, see section 7.3.4 of the KerML specification. For more details on the model, see section 8.3.3.3.4 of the KerML specification.

Members defined in Feature (39 members)

	`STD`	`R`
	`basic_feature`	`R`	The `last_chaining_feature` if one exists, otherwise this `Feature`.
	`cross_feature`	`R`	The second `chaining_feature` of the `crossed_feature` of the `owned_cross_subsetting` of this `Feature`, if it has one. Semantically, the values of the `cross_feature` of an end `Feature` must include all values of the end `Feature` obtained when navigating from values of the other end `Features` of the same `owning_type`.
	`direction`	`RW`	Indicates how values of this `Feature` are determined or used (as specified for the `FeatureDirectionKind`).
	`end_owning_type`	`R`	The `Type` that is related to this `Feature` by an `EndFeatureMembership` in which the `Feature` is an `owned_member_feature`.
	`explicit_direction`	`R`	Returns the direction this `Feature` has been declared with in the textual syntax.
	`feature_target`	`R`	The last of the `chaining_features` of this `Feature`, if it has any. Otherwise, this `Feature` itself.
	`feature_value`	`R`	The `FeatureValue` owned by this `Feature` if any.
	`feature_value_expression`	`R`	The feature value `Expression` of this `Feature` if any.
	`feature_value_member`	`R`	SysIDE specific accessor for manipulating `feature_value`.
	`featuring_types`	`R`	`Types` that feature this `Feature`, such that any instance in the domain of the `Feature` must be classified by all of these `Types`, including at least all the `featuring_types` of its `type_featurings`. If the `Feature` is chained, then the `featuring_types` of the first `Feature` in the chain are also `featuring_types` of the chained `Feature`.
	`first_chaining_feature`	`R`	The related `Feature` related by the first `owned_feature_chaining` if any.
	`is_composite`	`RW`	Whether the `Feature` is a composite `feature` of its `featuring_type`. If so, the values of the `Feature` cannot exist after its featuring instance no longer does.
	`is_composite_explicitly`	`R`	Returns `True` if this `Feature` has been declared `composite` in the textual syntax.
	`is_derived`	`RW`	Whether the values of this `Feature` can always be computed from the values of other `Features`.
	`is_end`	`RW`	Whether or not this `Feature` is an end `Feature`. An end `Feature` always has multiplicity 1, mapping each of its domain instances to a single co-domain instance. However, it may have a `cross_feature`, in which case values of the `cross_feature` must be the same as those found by navigation across instances of the `owning_type` from values of other end `Features` to values of this Feature. If the `owning_type` has n end `Features`, then the multiplicity, ordering, and uniqueness declared for the `cross_feature` of any one of these end `Features` constrains the cardinality, ordering, and uniqueness of the collection of values of that `Feature` reached by navigation when the values of the other n-1 end `Features` are held fixed.
	`is_end_explicitly`	`R`	Returns `True` if this `Feature` has been declared `end` in the textual syntax.
	`is_nonunique`	`RW`
	`is_ordered`	`RW`	Whether an order exists for the values of this `Feature` or not.
	`is_portion`	`RW`	Whether the values of this `Feature` are contained in the space and time of instances of the domain of the `Feature` and represent the same thing as those instances.
	`is_read_only`	`RW`	Whether the values of this `Feature` can change over the lifetime of an instance of the domain.
	`is_unique`	`RW`	Whether or not values for this `Feature` must have no duplicates or not.
	`last_chaining_feature`	`R`	The related `Feature` related by the last `owned_feature_chaining` if any.
	`owned_cross_feature`	`R`	The member `Feature` that is declared before any prefixes in the textual syntax.
	`owned_cross_feature_member`	`R`	SysIDE specific accessor for either owned crossing_feature or crossing_multiplicity. This is the member `Feature` that is declared before any prefixes in the textual syntax.
	`owned_cross_subsetting`	`R`	The one `owned_subsetting` of this `Feature`, if any, that is a `CrossSubsetting}, for which the Feature is the crossing_feature.`
	`owned_feature_chainings`	`R`	The `owned_relationships` of this `Feature` that are `FeatureChainings`, for which the `Feature` will be the `feature_chained`.
	`owned_feature_invertings`	`R`	The `owned_relationships` of this `Feature` that are `FeatureInvertings` and for which the `Feature` is the `feature_inverted`.
	`owned_redefinitions`	`R`	The `owned_subsettings` of this `Feature` that are `Redefinitions`, for which the `Feature` is the `redefining_feature`.
	`owned_reference_subsetting`	`R`	The one `owned_subsetting` of this `Feature`, if any, that is a `ReferenceSubsetting`, for which the `Feature` is the `referencing_feature`.
	`owned_subsettings`	`R`	The `owned_specializations` of this `Feature` that are `Subsettings`, for which the `Feature` is the `subsetting_feature`.
	`owned_type_featurings`	`R`	The `owned_relationships` of this `Feature` that are `TypeFeaturings` and for which the `Feature` is the `feature_of_type`.
	`owned_typings`	`R`	The `owned_specializations` of this `Feature` that are `FeatureTypings`, for which the `Feature` is the `typed_feature`.
	`owning_feature_membership`	`R`	The `FeatureMembership` that owns this `Feature` as an `owned_member_feature`, determining its `owning_type`.
	`owning_type`	`R`	The `Type` that is the `owning_type` of the `owning_feature_membership` of this `Feature`.
	`referenced_feature`	`R`	Returns the `Feature` this `Feature` references through `ReferenceSubsetting` if any.
	`referenced_feature_target`	`R`	Returns the `feature_target` of `referenced_feature`, i.e. `referenced_feature.feature_target`.
	`types`	`R`	`Types` that restrict the values of this `Feature`, such that the values must be instances of all the `types`. The types of a `Feature` are derived from its `typings` and the `types` of its `subsettings`. If the `Feature` is chained, then the `types` of the last `Feature` in the chain are also `types` of the chained `Feature`.
	`find_owned_cross_feature`

Members inherited from Type (36 members)

	`declared_multiplicity`	`R`	The owned multiplicity that is declared before the children block in the textual syntax.
	`declared_multiplicity_member`	`R`	SysIDE specific accessor for manipulating `declared_multiplicity`.
	`differencing_types`	`R`	The interpretations of a `Type` with `differencing_types` are asserted to be those of the first of those `Types`, but not including those of the remaining `Types`. For example, a `Classifier` might be the difference of a `Classifier` for people and another for people of a particular nationality, leaving people who are not of that nationality. Similarly, a feature of people might be the difference between a feature for their children and a `Classifier` for people of a particular sex, identifying their children not of that sex (because the interpretations of the children `Feature` that identify those of that sex are also interpretations of the `Classifier` for that sex).
	`directed_features`	`R`	The `features` of this `Type` that have a non-null `direction`.
	`disjoining_types`	`R`	The types that related to this `Type` through `owned_disjoinings`.
	`end_features`	`R`	All `features` of this `Type` with `is_end = true`.
	`feature_memberships`	`R`	The `FeatureMemberships` for `features` of this `Type`, which include all `owned_feature_memberships` and those `inherited_memberships` that are `FeatureMemberships` (but does not include any `imported_memberships`).
	`features`	`R`	The `owned_member_features` of the `feature_memberships` of this `Type`.
	`heritage`	`R`	The specializations and conjugations owned by this `Type`.
	`inherited_features`	`R`	All the `member_features` of the `inherited_memberships` of this `Type` that are `FeatureMemberships`.
	`inherited_memberships`	`R`	All `Memberships` inherited by this `Type` via `Specialization` or `Conjugation`. These are included in the derived union for the `memberships` of the `Type`.
	`inputs`	`R`	All `features` related to this `Type` by `FeatureMemberships` that have `direction` `in` or `inout`.
	`intersecting_types`	`R`	The interpretations of a `Type` with `intersecting_types` are asserted to be those in common among the `intersecting_types`, which are the `Types` derived from the `intersecting_type` of the `owned_intersectings` of this `Type`. For example, a `Classifier` might be an intersection of `Classifiers` for people of a particular sex and of a particular nationality. Similarly, a feature for people’s children of a particular sex might be the intersection of a `Feature` for their children and a `Classifier` for people of that sex (because the interpretations of the children `Feature` that identify those of that sex are also interpretations of the Classifier for that sex).
	`is_abstract`	`RW`	Indicates whether instances of this `Type` must also be instances of at least one of its specialized `Types`.
	`is_conjugated`	`R`	Indicates whether this `Type` has an `owned_conjugator`.
	`is_sufficient`	`RW`	Whether all things that meet the classification conditions of this `Type` must be classified by the `Type`.
	`is_sufficient_explicitly`	`R`	Returns `True` if this `Type` was declared as `sufficient` in the textual syntax.
	`multiplicity`	`R`	An `owned_member` of this `Type` that is a `Multiplicity`, which constraints the cardinality of the `Type`. If there is no such `owned_member`, then the cardinality of this `Type` is constrained by all the `Multiplicity` constraints applicable to any direct supertypes.
	`outputs`	`R`	All `features` related to this `Type` by `FeatureMemberships` that have `direction` `out` or `inout`.
	`owned_conjugator`	`R`	A `Conjugation` owned by this `Type` for which the `Type` is the `original_type`.
	`owned_differencings`	`R`	The `owned_relationships` of this `Type` that are `Differencings`, having this `Type` as their `type_differenced`.
	`owned_directed_features`	`R`	The `directed_features` that are owned by this `Type`.
	`owned_disjoinings`	`R`	The `owned_relationships` of this `Type` that are `Disjoinings`, for which the `Type` is the `type_disjoined` `Type`.
	`owned_end_features`	`R`	All `end_features` of this `Type` that are `owned_features`.
	`owned_feature_memberships`	`R`	The `owned_memberships` of this `Type` that are `FeatureMemberships`, for which the `Type` is the `owning_type`. Each such `FeatureMembership` identifies an `owned_feature` of the `Type`.
	`owned_features`	`R`	The `owned_member_features` of the `owned_feature_memberships` of this `Type`.
	`owned_inputs`	`R`	The `inputs` that are owned by this `Type`.
	`owned_intersectings`	`R`	The `owned_relationships` of this `Type` that are `Intersectings`, have the `Type` as their `type_intersected`.
	`owned_outputs`	`R`	The `outputs` that are owned by this `Type`.
	`owned_specializations`	`R`	The `owned_relationships` of this `Type` that are `Specializations`, for which the `Type` is the `specific` `Type`.
	`owned_unionings`	`R`	The `owned_relationships` of this `Type` that are `Unionings`, having the `Type` as their `type_unioned`.
	`type_relationships`	`R`	The other type, feature relationships and `FeatureChainings` owned by this `Type`.
	`unioning_types`	`R`	The interpretations of a `Type` with `unioning_types` are asserted to be the same as those of all the `unioning_types` together, which are the `Types` derived from the `unioning_type` of the `owned_unionings` of this `Type`. For example, a `Classifier` for people might be the union of `Classifiers` for all the sexes. Similarly, a feature for people’s children might be the union of features dividing them in the same ways as people in general.
	`conforms`
	`direction_of`
	`specializes`

Members inherited from Element (23 members)

	`comments`	`R`	The owned `Comments` related by `owned_relationships`.
	`declared_name`	`RW`	The declared name of this `Element`.
	`declared_short_name`	`RW`	An optional alternative name for the `Element` that is intended to be shorter or in some way more succinct than its primary `name`. It may act as a modeler-specified identifier for the `Element`, though it is then the responsibility of the modeler to maintain the uniqueness of this identifier within a model or relative to some other context.
	`documentation`	`R`	The Documentation owned by this Element.
	`element_id`	`RW`	The globally unique identifier for this Element. This is intended to be set by tooling, and it must not change during the lifetime of the Element.
	`is_implied_included`	`R`	Whether all necessary implied Relationships have been included in the `owned_relationships` of this Element. This property may be true, even if there are not actually any `owned_relationships` with `is_implied = true`, meaning that no such Relationships are actually implied for this Element. However, if it is false, then `owned_relationships` may not contain any implied Relationships. That is, either all required implied Relationships must be included, or none of them.
	`is_library_element`	`R`	Whether this Element is contained in the ownership tree of a library model.
	`metadata`	`R`	The owned metadata related by `owned_relationships`.
	`name`	`R`	The name to be used for this `Element` during name resolution within its `owning_namespace`. This is derived using the `effective_name()` operation. By default, it is the same as the `declared_name`, but this is overridden for certain kinds of `Elements` to compute a `name` even when the `declared_name` is null.
	`owned_annotations`	`R`	The `owned_relationships` of this `Element` that are `Annotations`, for which this `Element` is the `annotated_element`.
	`owned_elements`	`R`	The Elements owned by this Element, derived as the owned_related_elements of the owned_relationships of this Element.
	`owned_relationships`	`R`	The Relationships for which this Element is the owning_related_element.
	`owner`	`R`	The owner of this Element, derived as the `owning_related_element` of the `owning_relationship` of this Element, if any.
	`owning_membership`	`R`	The `owning_relationship` of this `Element`, if that `Relationship` is a `Membership`.
	`owning_namespace`	`R`	The `Namespace` that owns this `Element`, which is the `membership_owning_namespace` of the `owning_membership` of this `Element`, if any.
	`owning_relationship`	`R`	The Relationship for which this Element is an owned_related_element, if any.
	`qualified_name`	`R`	The full ownership-qualified name of this `Element`, represented in a form that is valid according to the KerML textual concrete syntax for qualified names (including use of unrestricted name notation and escaped characters, as necessary). The `qualified_name` is null if this `Element` has no `owning_namespace` or if there is not a complete ownership chain of named `Namespaces` from a root `Namespace` to this `Element`.
	`scoped_owner`	`R`	The owner of this `Element` as the parent of `owning_membership` or `owning_relationship` otherwise.
	`sema_state`	`RW`	The state of semantic resolution for this `Element`. Based on this, sema may skip elements to avoid duplicate work, e.g. when resolving elements in a group of related documents.
	`short_name`	`R`	The short name to be used for this `Element` during name resolution within its `owning_namespace`. This is derived using the `effective_short_name()` operation. By default, it is the same as the `declared_short_name`, but this is overridden for certain kinds of `Elements` to compute a `short_name` even when the `declared_name` is null.
	`textual_representations`	`R`	The `TextualRepresentations` that annotate this `Element`.
	`__str__`
	`matches_qualified_name`

 Attributes

STD: tuple[type[syside.Feature], ...] = ()

property basic_feature: syside.Feature: The last_chaining_feature if one exists, otherwise this Feature.

property cross_feature: syside.Feature | None: The second chaining_feature of the crossed_feature of the owned_cross_subsetting of this Feature, if it has one. Semantically, the values of the cross_feature of an end Feature must include all values of the end Feature obtained when navigating from values of the other end Features of the same owning_type.

property direction: syside.FeatureDirectionKind | None: Indicates how values of this Feature are determined or used (as specified for the FeatureDirectionKind).

property end_owning_type: syside.Type | None: The Type that is related to this Feature by an EndFeatureMembership in which the Feature is an owned_member_feature.

property explicit_direction: syside.FeatureDirectionKind | None: Returns the direction this Feature has been declared with in the textual syntax.

property feature_target: syside.Feature: The last of the chaining_features of this Feature, if it has any. Otherwise, this Feature itself.

property feature_value: syside.FeatureValue | None: The FeatureValue owned by this Feature if any.

property feature_value_expression: syside.Expression | None: The feature value Expression of this Feature if any.

property feature_value_member: syside.FeatureValueAccessor: SysIDE specific accessor for manipulating feature_value.

property featuring_types: syside.LazyIterator[syside.Type]: Types that feature this Feature, such that any instance in the domain of the Feature must be classified by all of these Types, including at least all the featuring_types of its type_featurings. If the Feature is chained, then the featuring_types of the first Feature in the chain are also featuring_types of the chained Feature.

property first_chaining_feature: syside.Feature | None: The related Feature related by the first owned_feature_chaining if any.

property is_composite: bool: Whether the Feature is a composite feature of its featuring_type. If so, the values of the Feature cannot exist after its featuring instance no longer does.

property is_composite_explicitly: bool: Returns True if this Feature has been declared composite in the textual syntax.

property is_derived: bool: Whether the values of this Feature can always be computed from the values of other Features.

property is_end: bool: Whether or not this Feature is an end Feature. An end Feature always has multiplicity 1, mapping each of its domain instances to a single co-domain instance. However, it may have a cross_feature, in which case values of the cross_feature must be the same as those found by navigation across instances of the owning_type from values of other end Features to values of this Feature. If the owning_type has n end Features, then the multiplicity, ordering, and uniqueness declared for the cross_feature of any one of these end Features constrains the cardinality, ordering, and uniqueness of the collection of values of that Feature reached by navigation when the values of the other n-1 end Features are held fixed.

property is_end_explicitly: bool: Returns True if this Feature has been declared end in the textual syntax.

property is_nonunique: bool

property is_ordered: bool: Whether an order exists for the values of this Feature or not.

property is_portion: bool: Whether the values of this Feature are contained in the space and time of instances of the domain of the Feature and represent the same thing as those instances.

property is_read_only: bool: Whether the values of this Feature can change over the lifetime of an instance of the domain.

property is_unique: bool: Whether or not values for this Feature must have no duplicates or not.

property last_chaining_feature: syside.Feature | None: The related Feature related by the last owned_feature_chaining if any.

property owned_cross_feature: syside.Feature | None: The member Feature that is declared before any prefixes in the textual syntax.

property owned_cross_feature_member: syside.OwnedFeatureAccessor: SysIDE specific accessor for either owned crossing_feature or crossing_multiplicity. This is the member Feature that is declared before any prefixes in the textual syntax.

property owned_cross_subsetting: syside.CrossSubsetting | None: The one owned_subsetting of this Feature, if any, that is a CrossSubsetting}, for which the Feature is the crossing_feature.

property owned_feature_chainings: syside.LazyIterator[syside.FeatureChaining]: The owned_relationships of this Feature that are FeatureChainings, for which the Feature will be the feature_chained.

property owned_feature_invertings: syside.LazyIterator[syside.FeatureInverting]: The owned_relationships of this Feature that are FeatureInvertings and for which the Feature is the feature_inverted.

property owned_redefinitions: syside.LazyIterator[syside.Redefinition]: The owned_subsettings of this Feature that are Redefinitions, for which the Feature is the redefining_feature.

property owned_reference_subsetting: syside.ReferenceSubsetting | None: The one owned_subsetting of this Feature, if any, that is a ReferenceSubsetting, for which the Feature is the referencing_feature.

property owned_subsettings: syside.LazyIterator[syside.Subsetting]: The owned_specializations of this Feature that are Subsettings, for which the Feature is the subsetting_feature.

property owned_type_featurings: syside.LazyIterator[syside.TypeFeaturing]: The owned_relationships of this Feature that are TypeFeaturings and for which the Feature is the feature_of_type.

property owned_typings: syside.LazyIterator[syside.FeatureTyping]: The owned_specializations of this Feature that are FeatureTypings, for which the Feature is the typed_feature.

property owning_feature_membership: syside.FeatureMembership | None: The FeatureMembership that owns this Feature as an owned_member_feature, determining its owning_type.

property owning_type: syside.Type | None: The Type that is the owning_type of the owning_feature_membership of this Feature.

property referenced_feature: syside.Feature | None: Returns the Feature this Feature references through ReferenceSubsetting if any.

property referenced_feature_target: syside.Feature | None: Returns the feature_target of referenced_feature, i.e. referenced_feature.feature_target.

property types: syside.LazyIterator[syside.Type]: Types that restrict the values of this Feature, such that the values must be instances of all the types. The types of a Feature are derived from its typings and the types of its subsettings. If the Feature is chained, then the types of the last Feature in the chain are also types of the chained Feature.

 Methods

find_owned_cross_feature() → syside.Feature | None: Find the owned cross feature by potentially checking children. This is needed for spec that defined owned cross feature as the first member feature that is not a MetadataFeature or Multiplicity of an end feature. Since SysML does not allow member features (member keyword in KerML), this is equivalent to owned_cross_feature in SysML.

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	`children`	`R`	The elements enclosed by curly brackets in textual syntax.
	`members`	`R`	The set of all member `Elements` of this `Namespace`, which are the `member_elements` of all `memberships` of the `Namespace`.
	`memberships`	`R`	All `Memberships` in this `Namespace`, including (at least) the union of `owned_memberships` and `imported_memberships`.
	`owned_imports`	`R`	The `owned_relationships` of this `Namespace` that are `Imports`, for which the `Namespace` is the `import_owning_namespace`.
	`owned_members`	`R`	The owned `members` of this `Namespace`, which are the `owned_member_elements` of the `owned_memberships` of the `Namespace`.
	`owned_memberships`	`R`	The `owned_relationships` of this `Namespace` that are `Memberships`, for which the `Namespace` is the `membership_owning_namespace`.
	`prefixes`	`R`	Metadata prefixes, prefixed with `#` in textual syntax.
	`__getitem__`
	`get_member`
	`get_membership`

	`cst_node`	`R`
	`document`	`R`
	`parent`	`R`
	`__hash__`
	`cast`
	`isinstance`
	`try_cast`