Indicator catalog development

File structure

• Catalog: src/{category}/{Indicator}/{Indicator}.Catalog.cs
• Location: Same directory as {Indicator}.Models.cs

Builder pattern

public static partial class Ema
{
    /// <summary>
    /// EMA Common Base Listing
    /// </summary>
    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("Ema", "EMA", ResultType.Default, isReusable: true)
            .Build();

    /// <summary>
    /// EMA Series Listing
    /// </summary>
    internal static readonly IndicatorListing SeriesListing =
        new CatalogListingBuilder(CommonListing)
            .WithStyle(Style.Series)
            .WithMethodName("ToEma")
            .Build();

    /// <summary>
    /// EMA Stream Listing
    /// </summary>
    internal static readonly IndicatorListing StreamListing =
        new CatalogListingBuilder(CommonListing)
            .WithStyle(Style.Stream)
            .WithMethodName("ToEmaHub")
            .Build();

    /// <summary>
    /// EMA Buffer Listing
    /// </summary>
    internal static readonly IndicatorListing BufferListing =
        new CatalogListingBuilder(CommonListing)
            .WithStyle(Style.Buffer)
            .WithMethodName("ToEmaList")
            .Build();
}

Method naming conventions

Critical: .WithMethodName() must be in style-specific listings, NOT in CommonListing.

Required parameter patterns

• Use AddParameter<T>() for basic types (int, double, bool)
• Use AddEnumParameter<T>() for enum types
• Use AddDateParameter() for DateTime parameters
• Use AddSeriesParameter() for IReadOnlyList<T> where T : IReusable
• MUST set minimum and maximum for all numeric parameters

Required result patterns

• dataName MUST match property name in Models file exactly
• Set isReusable: true ONLY for property mapping to IReusable.Value
• ISeries models: ALL results MUST have isReusable: false
• Exactly ONE result with isReusable: true per IReusable indicator

Categories

Registration

Add to src/_common/Catalog/Catalog.Listings.cs in PopulateCatalog():

_catalog.Add(Ema.SeriesListing);
_catalog.Add(Ema.StreamListing);
_catalog.Add(Ema.BufferListing);

Register in alphabetical order by indicator name.

Testing

Create tests/indicators/{folder}/{Indicator}/{Indicator}.Catalog.Tests.cs:

[TestClass]
public class EmaCatalogTests : TestBase
{
    [TestMethod]
    public void EmaSeriesListing()
    {
        var listing = Ema.SeriesListing;
        listing.Name.Should().Be("Exponential Moving Average");
        listing.Style.Should().Be(Style.Series);
        listing.MethodName.Should().Be("ToEma");
    }
}

Prohibited patterns

• ❌ .WithMethodName() in CommonListing (MUST be in style-specific listings)
• ❌ Wrong indicator method name (breaks extension method discovery)
• ❌ isReusable: true for ISeries models (violates interface contract)
• ❌ Multiple isReusable: true results (ambiguous Value mapping)

Last updated: December 31, 2025