StructuralFeature

UserPreferences

StructuralFeature is the base class for "method-exporting properties", such as model.Attribute, model.Collection, etc.

The following class members affect how ?StructuralFeatures are used:

isDerived

Used for "abstract based models". If True, it raises NotImplementedError on get, and acts immutable (see isChangeable).

type: bool
default: False
set by: ?DerivedFeature (True)

isChangeable

Is the slot mutable? If False, it prevents the attribute from being set or unset.

type: bool
default: lambda self: not self.isDerived
set by: structField (True), ?DerivedFeature (True indirectly)

isComposite

XXX (is this deprecated, or just obscure?)

type: bool
default: False
set by: Users (?)

isOrdered

Is the slot an ordered collection? If True, it enables the insertBefore%s accessor. Note that it is only meaningful if isMany is also True.

type: bool
default: False
set by: Sequence (True)

useSlot

Should this slot use a prefixed __dict__ slot? If True, the implementation uses _f_%s as the slot name, otherwise %s is used.

type: bool
default: False
set by: Users (?)

lowerBound

The minimum number of elements that can occupy this slot. 0 means that a value is not required (see isRequired). Integers less than 0 are unchecked degenerate values.

type: int
default: 0
set by: XXX

upperBound

The maximum number of elements that can occupy this slot. None means no limit, 1 means that this slot is not a collection (see isMany). Integers less than 1 are unchecked degenerate values.

type: int or None
default: None
set by: Attribute (1), structField (1).

isRequired

Is a value required for this slot?

type: bool
default: lambda self: self.lowerBound > 0
set by: Attribute (True indirectly), structField (True indirectly)

isMany

Is this slot a collection? If True, enables the add, replace, and remove accessors and also changes the semantics of get and set.

type: bool
default: lambda self: self.upperBound <> 1
set by: Atttribute (False indirectly), structField (False indirectly)

referencedEnd

XXX (something to do with link and unlink notifications if is not None).

type: ComponentName (?) or None
default: None
set by: Users (?)

referencedType

XXX (The type that elements in this slot are allowed to have? Used by users when subclassing Attribute, possibly others)

type: ComponentName or None
default: None
set by: Users (?)

syntax

XXX (Syntax rule for this feature, looks like it's used for documentation/help)

type: None or fmtparse.IRule
default: None
set by: Users (?)

separator

XXX (parsing separator between multivalues, looks like it's used for documentation/help)

type: str
default: ''
set by: Users (?)

sepMayTerm

XXX (Can separator occur after last value?)

type: bool
default: False
set by: Users (?)

canBeEmpty

XXX

type: bool
default: False
set by: Users (?)

includeInRepr

XXX (Include feature in default Immutable.__repr__?)

type: bool
default: True
set by: Users (?)

offerAs

XXX

type: IBasicSequence (?)
default: ()
set by: Users (?)

uponAssembly

XXX

type: bool
default: False
set by: Users (?)

permissionNeeded

XXX (IGuardedDescriptor, declared in peak.security)

type: IGuardedDescriptor or None
default: None
set by: Users (?)