HiLang 2.5.50

• .NETStandard 2.0

  • FSharp.Core (>= 10.1.203)
  • FsLexYacc (>= 11.3.0)
  • FsLexYacc.Runtime (>= 11.3.0)
  • Microsoft.CodeAnalysis.CSharp (>= 5.3.0)

https://www.cepheis.com/hiperspace/20260424
# Overview
This release is a minor update to support the presentation Cube data in  Graph views with **Hiperspace.DB**, and minor updated to external references.
## Fact enhancement
A specific `ICubeFact<TFact>` inteface has been added to include `public IEnumerable<TFact> DrillDown(Type dimension);` for generic drilldown from one Cube to the next level when viewed in **Hiperspace.DB**.

The `ICubeDimension` interface now has a `GetCube()` function to get the named `ICubeFact` for use with a **PivotTable** view of the *Cube* through **Hiperspace.DB**.

## SubSpace enhancement
`SubSpaceParameters` has been enhanced to include `TransactionalPolicy`

|Policy|Notes|
|-|-|
|NotTransactional|Indicates that the Space is not transactional|
|Transactional|Specifies that a new transaction should be started|
|ParentTransaction|Indicates that the space participates in the transaction of its parent space|
|ContinueTransaction|Transaction is a continuation of a prior (long-running) transaction|

---

## Hilang enhancement
Added support sdupport for Cube aggregation of views in addition to {*entity, segment, aspect*}.

Consider the model where there are seperate *entitites* for {*FX, FI, EQ*} Trades that have different values for Entities, Bonds, Foreign Exchange, but can all be *viewed* as a Trade that has a booking_id, and a valuation (NPV).  This change adds support for **Cube** analytics of *views*  combining all trades in all entities that provide the view.

```
type Banking.TradeBase
(
Id : String
)
{
Book : Banking.Book,
@CubeMeasure(Aggregate.Sum)
NPV : Decimal
};

@CubeFact
view Banking.Trade : Banking.TradeBase;

entity Banking.FI.Trade : Banking.TradeBase = Banking.Trade();
entity Banking.FX.Trade : Banking.TradeBase = Banking.Trade();
entity Banking.EQ.Trade : Banking.TradeBase = Banking.Trade();

@CubeDimension
entity Banking.Book ( Id : String ) [ Trades : Banking.Trade (Book = this)];
```
When the schema is compiled with [HiLang](HiLang), `Banking.Book` has an additional property `Trade_Cube`  that aggregates NPV over the full set trades that can be *viewed* as a `Banking.Trade`.

### Enhanced List support
Keys in a hilang element can be:
* A Value including value elements defined in Hilang and primatives (e.g. String, Int32, Guid, etc)
* A Reference to an entity (only the Key-part of the referened entity is serialised)
* A List of Values (e.g. List<String>) but not a Set<> since a Set order can change

Key support for `List<>` in keys has been extended to include Keys of Lists of Values of Lists of Values, that can be placed in a `SortedSet`.  Examples include [FINIOS CDM](https://www.finos.org/common-domain-model) that supports complex identifiers that include list of identifiers

```
value CDM.PartyIdentifier ( identifier : String );
entity CDM.Party ( partyId : CDM.PartyIdentifier );
value CDM.PriceQuantity;
value CDM.AssetIdentifier
(
   identifer : String,
   version : Int32
);
value CDM.Identifer
(
   assignedIdentifier : List<CDM.AssetIdentifier>,
   issuerReference : CDM.Party,
   issuer : String
);
entity CDM.TradeLot
(
   lotIdentifier : List<CDM.Identifer>
)
{
   priceQuantity : List<CDM.PriceQuantity>
};
```
In this example `CDM.TradeLot` has a key that is a  `List<CDM.Identifer>` which itself contains a `List<CDM.AssetIdentifier>`.  Lists are supported in [HiLang](HiLang) models since the they can be unambiguously serialised to a store and retrived later.  **NB** `CDM.Identifer` contains a reference to `CDM.Party` which is a *entity* so only the *key* is stored, with `CDM.Party` retrived only when needed.