CircularAttribute

An attribute of a node type T with value of type U which has a circular definition. The value of the attribute is computed by the function f which may itself use the value of the attribute. init specifies an initial value for the attribute. The attribute (and any circular attributes on which it depends) are evaluated until no value changes (i.e., a fixed point is reached). The final result is memoised so that subsequent evaluations return the same value.

This code implements the basic circular evaluation algorithm from "Circular Reference Attributed Grammars - their Evaluation and Applications", by Magnusson and Hedin from LDTA 2003.

Source: AttributionCore.scala

Linear Supertypes

Attribute[T, U], (T) ⇒ U, AnyRef, Any

Instance Constructors

new CircularAttribute(name: String, init: U, f: (T) ⇒ U)

Value Members

final def !=(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def !=(arg0: Any): Boolean

Definition Classes
Any
final def ##(): Int

Definition Classes
AnyRef → Any
final def ==(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def ==(arg0: Any): Boolean

Definition Classes
Any
def andThen[A](g: (U) ⇒ A): (T) ⇒ A

Definition Classes
Function1
Annotations
@unspecialized()
def apply(t: T): U

Return the value of this attribute for node t.
Return the value of this attribute for node t. Essentially Figure 6 from the CRAG paper, plus the READY optimisation (section 3.3).

Definition Classes
CircularAttribute → Function1
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def compose[A](g: (A) ⇒ T): (A) ⇒ U

Definition Classes
Function1
Annotations
@unspecialized()
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hasBeenComputedAt(t: T): Boolean

Has the value of this attribute at t already been computed or not?
def hashCode(): Int

Definition Classes
AnyRef → Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
val memo: Memoiser[T, U]

Backing memo table.
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def reportCycle(t: T): U

Report a cycle in the calculation of this attribute discovered when evaluating the attribute on value t.
Report a cycle in the calculation of this attribute discovered when evaluating the attribute on value t. Throws an IllegalStateException.

Definition Classes
Attribute
def reset(): Unit

Immediately reset this attribute's memoisation cache.
def safef(t: T): U

Run the semantic function f in a safe manner.
Run the semantic function f in a safe manner. We need to guard against f throwing an exception which aborts the computation, since we could then leave the global circular attribute state in a funny state.
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String

The attribute's string representation is its name.
The attribute's string representation is its name.

Definition Classes
Attribute → Function1 → AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )

class CircularAttribute[T, U] extends Attribute[T, U]

Instance Constructors

new CircularAttribute(name: String, init: U, f: (T) ⇒ U)

Value Members

final def !=(arg0: AnyRef): Boolean

final def !=(arg0: Any): Boolean

final def ##(): Int

final def ==(arg0: AnyRef): Boolean

final def ==(arg0: Any): Boolean

def andThen[A](g: (U) ⇒ A): (T) ⇒ A

def apply(t: T): U

final def asInstanceOf[T0]: T0

def clone(): AnyRef

def compose[A](g: (A) ⇒ T): (A) ⇒ U

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

final def getClass(): Class[_]

def hasBeenComputedAt(t: T): Boolean

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

val memo: Memoiser[T, U]

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

def reportCycle(t: T): U

def reset(): Unit

def safef(t: T): U

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

Inherited from Attribute[T, U]

Inherited from (T) ⇒ U

Inherited from AnyRef

Inherited from Any

Ungrouped