indicator-catalog

# Indicator catalog development The catalog drives automated execution, code generation, and charting, so every listing must bind to a real method, parameter, and result property. The tests in `tests/Library/Common/Catalog/` enforce most rules below across every listing. ## Listing file `src/Indicators/{folder}/{Name}/{Name}.Catalog.cs` declares one `CommonListing` and one listing per supported style. `src/Indicators/e-j/Ema/Ema.Catalog.cs` is the reference: ```csharp public static partial class Ema { internal static readonly IndicatorListing CommonListing = new CatalogListingBuilder() .WithName("Exponential Moving Average") .WithId("EMA") .WithCategory(Category.MovingAverage) .AddParameter<int>("lookbackPeriods", "Lookback Period", description: "Number of periods for the EMA calculation", isRequired: true, defaultValue: 20, minimum: 2, maximum: 250) .AddResult(nameof(EmaResult.Ema), "EMA", IndicatorResult.PricePane, ResultType.Default, isReusable: true) .Build(); internal static readonly IndicatorListing SeriesListing = new CatalogListingBuilder(CommonListing) .WithStyle(Style.Series) .WithMethodName("ToEma") .Build(); // BufferListing: Style.Buffer + "ToEmaList"; StreamListing: Style.Stream + "ToEmaHub" } ``` - Set `.WithMethodName()` only on style listings: `To{Name}` for Series, `To{Name}List` for Buffer, `To{Name}Hub` for Stream. - `Build()` derives `ResultRecordType` from the method name, so a method of the wrong style reports the wrong result shape. - `WithId` sets the UIID that names the regression baseline file (`{uiid-lowercase}.standard.json`) and the `Catalog.Get(id, style)` lookup. - Pick the `Category` an existing peer uses; MACD, Ichimoku, and Pivot Points are `PriceTrend`, and Beta and ATR are `PriceCharacteristic`. ## Parameters | Builder method | Parameter type | | -------------- | -------------- | | `AddParameter<T>()` | `int`, `double`, `decimal`, and other primitive values; always pass `minimum` and `maximum` | | `AddEnumParameter<T>()` | Enums | | `AddDateParameter()` | `DateTime` | | `AddSeriesParameter()` | An `IReadOnlyList<IReusable>` input, such as the comparison series of Beta, Correlation, and PRS | - `parameterName` matches the method's parameter name exactly; a mismatch makes a catalog-bound caller silently receive the default instead of the supplied value. - Declare parameters as an unbroken run in signature order. `ListingExecutor` binds them positionally and picks an overload by argument count. - Set `isRequired: false` exactly when the C# signature gives the parameter a default, and set `defaultValue` equal to that C# default. - When omitting the argument instead selects a shorter overload, use `isRequired: false` only if the listing declares no `defaultValue` (VWAP `startDate`). If the shorter overload behaves differently from the advertised default (`ToPrs(sourceEval, sourceBase)` computes no `PrsPercent`), use `isRequired: true`; callers reach the shorter form with `WithoutParam(name)` at execution time. ## Results `AddResult(dataName, displayName, chartPane, dataType, isReusable)`: - `dataName` is `nameof(TResult.Property)`, never a string literal, so a renamed property fails the build. `displayName` is a literal human label. - `chartPane` is `IndicatorResult.PricePane` for a value at price level, a shared pane name (conventionally the indicator name, such as `"Macd"`) for results with common non-price units, and `null` for a non-numeric result such as a pattern match. - `isReusable: true` marks exactly one result on an `IReusable` model, the property that `Value` returns. An `ISeries` model marks none. `Build()` throws when more than one is marked. - `ResultType` sets the chart form: `Default`, `Centerline`, `Channel`, `Bar`, `BarStacked`, or `Point`. ## Registration and shape snapshot Register each listing inside `PopulateCatalog()` in `src/Common/Catalog/Catalog.Listings.cs`. Blocks sort alphabetically by indicator ID, are separated by a blank line, and open with a `// {ID} ({Full Name})` comment, or `// {Full Name}` when no abbreviation is conventional. Within a block the order is Buffer, Series, Stream: ```csharp // EMA (Exponential Moving Average) _listings.Add(Ema.BufferListing); _listings.Add(Ema.SeriesListing); _listings.Add(Ema.StreamListing); // Beta _listings.Add(Beta.SeriesListing); ``` Adding or changing a parameter or result changes `tests/Library/TestData/catalog/shape.snapshot.txt`. Regenerate it, review the diff, then rerun the test without the variable to confirm it passes; the regeneration run reports Inconclusive: ```bash UPDATE_CATALOG_SHAPE=1 dotnet test tests/Library/Tests.Indicators.csproj --filter CatalogShapeMatchesSnapshot ``` ## Tests `tests/Library/Indicators/{folder}/{Name}/{Name}CatalogTests.cs` declares `public class {Name}CatalogTests : TestBase` in namespace `Catalogging`, with one `{Name}{Style}_InCatalog_ReturnsAllVariants()` method per style asserting `Name`, `Uiid`, `Style`, `Category`, `MethodName`, and the parameter and result counts. `tests/Library/Indicators/t-z/Wma/WmaCatalogTests.cs` is a minimal example. The catalog-wide tests verify method binding per style, `dataName` and `parameterName` resolution, parameter order, `isRequired` and default agreement with the C# signature, chart panes, and the shape snapshot. They do not check names, categories, or value ranges, so keep the per-indicator test. ## Do not do these - Do not call `.WithMethodName()` on `CommonListing`. - Do not write a `dataName` as a string literal where `nameof` can reach the member. - Do not mark `isReusable: true` on an `ISeries` model or on more than one result. - Do not set `isRequired: false` with a `defaultValue` the C# signature does not apply when the argument is omitted. - Do not hand-edit `shape.snapshot.txt`; regenerate it.