Class ChangeDag<TNode, TIdentifier, TVisitor>

Generic base class for logic around modifying immutable nodes in a directed acyclic graph, propagating any changes up the dependency tree. This allows "change X" logic to be shared across Expression and Table classes.

Inheritance

Object

ChangeDag<TNode, TIdentifier, TVisitor>

ChangeExpressions

ChangeTables

Inherited Members

Object.Equals(Object)

Object.Equals(Object, Object)

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ReferenceEquals(Object, Object)

Object.ToString()

Namespace: Mangrove.MetricSetTransformers.Utilities

Assembly: MetricSetTransformers.dll

Syntax

public abstract class ChangeDag<TNode, TIdentifier, TVisitor>
    where TNode : class, ICloneable<TNode>, IVisitable<TVisitor> where TIdentifier : class

Type Parameters

Name	Description
TNode	The base type of node to be changed. Probably either Table or Expression.
TIdentifier	The type of a node's "identifier", e.g. String for Table nodes and Table for Expression nodes.
TVisitor	Type of visitor that nodes accept. Note: any subclass must implement this type. Sadly, this cannot be expressed as a type constraint because C# only allows constraints of the form T : ....

Constructors

ChangeDag()

Declaration

public ChangeDag()

Properties

Mapping

Declaration

protected IDictionary<TNode, TNode> Mapping { get; }

Property Value

Type	Description
IDictionary<TNode, TNode>

Methods

ChangeIdentifier(TNode)

Override this to change the identifier node has.

Declaration

protected virtual TIdentifier ChangeIdentifier(TNode node)

Parameters

Type	Name	Description
TNode	node

Returns

Type	Description
TIdentifier

Identifier(TNode)

Non-unique "identifier" that node has.

Declaration

protected abstract TIdentifier Identifier(TNode node)

Parameters

Type	Name	Description
TNode	node

Returns

Type	Description
TIdentifier

ReplaceParent(TNode, TNode, TNode)

Override this to replace newParent, given the information of oldNode and newNode.

Declaration

protected virtual TNode ReplaceParent(TNode oldNode, TNode newNode, TNode newParent)

Parameters

Type	Name	Description
TNode	oldNode
TNode	newNode
TNode	newParent

Returns

Type	Description
TNode

Reset()

Clear the internal state.

Declaration

public void Reset()

UberVisit<TSubnode>(TSubnode, Func<TSubnode, TNode>)

Another version of "uber visit" with fewer type parameters, when the node's identifier has the same type as the "generic" node type TNode.

Declaration

protected void UberVisit<TSubnode>(TSubnode node, Func<TSubnode, TNode> change)
    where TSubnode : TNode, ICloneable<TSubnode, TIdentifier, TNode>

Parameters

Type	Name	Description
TSubnode	node
Func<TSubnode, TNode>	change

Type Parameters

Name	Description
TSubnode

UberVisit<TSubnode, TSubidentifier>(TSubnode, Func<TSubnode, TNode>)

"Master" visit function containing the core logic for doing nothing if a node has already been visited, visiting all its direct parents, replacing the identifier or any parents if needed, and finally changing the node itself. This removes nearly all boilerplace from the individual "visit" methods in ChangeExpressions and ChangeTables.

Declaration

protected void UberVisit<TSubnode, TSubidentifier>(TSubnode node, Func<TSubnode, TNode> change)
    where TSubnode : TNode, ICloneable<TSubnode, TSubidentifier, TNode> where TSubidentifier : class, TIdentifier

Parameters

Type	Name	Description
TSubnode	node	The node being visited.
Func<TSubnode, TNode>	change	The "change" function for TSubnode.

Type Parameters

Name	Description
TSubnode	Type of the (directed acyclic graph) node being visited.
TSubidentifier	Type of the identifier that node has. If ChangeIdentifier(TNode) is overridden, the overriding method must ensure it returns objects of types compatible with this.

Operators

Implicit(ChangeDag<TNode, TIdentifier, TVisitor> to TVisitor)

Since we require that any concrete subclass implement TVisitor, define an implicit conversion of this class to that type.

Declaration

public static implicit operator TVisitor(ChangeDag<TNode, TIdentifier, TVisitor> changeDag)

Parameters

Type	Name	Description
ChangeDag<TNode, TIdentifier, TVisitor>	changeDag

Returns

Type	Description
TVisitor

Remarks

The intermediate cast to Object is needed because the C# compiler can't guarantee that this is a TVisitor. See: https://stackoverflow.com/q/7978316 .

Extension Methods

ObjectExtensions.EventId(Object)