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ExtendedPayroll

README.md

ExtendedPayroll Example

A practical composite function example for ExtendedTenant, demonstrating how to extend the engine's built-in scripting functions with custom C# classes.

This is the reference implementation for the Extended Functions wiki tutorial.

Scenario

One employee, one wage type. The Salary value is not read directly via a No-Code expression — it is delegated to a composite function class, demonstrating the full three-step pattern for function extension.

Employee Salary Period
Mario Nuñez 5 000 January 2023

Composite Function Pattern

Function extension involves three steps:

Step 1 — Implement business logic (CompositeWageTypeValueFunction.cs)

A plain C# class that receives WageTypeValueFunction as a constructor argument and exposes domain methods:

public class CompositeWageTypeValueFunction(WageTypeValueFunction function)
{
    private WageTypeValueFunction Function { get; } = function
        ?? throw new ArgumentNullException(nameof(function));

    public decimal GetSalary()
    {
        return Function.CaseValue["Salary"];
    }
}

Step 2 — Register the extension (WageTypeValueFunction.cs)

Extend the engine's WageTypeValueFunction using partial to expose the composite class as a named property:

public partial class WageTypeValueFunction
{
    private CompositeWageTypeValueFunction function;
    public CompositeWageTypeValueFunction MyRegulation => function ??= new(this);
}

The property MyRegulation is now available in every valueExpression of this regulation — lazy-initialized on first access.

Step 3 — Call from wage type (Payroll.json)

The composite method is called directly from the wage type valueExpression:

{
  "wageTypeNumber": 100,
  "name": "Salary",
  "valueExpression": "MyRegulation.GetSalary()"
}

Regulation: ExtendedRegulation

Cases

Case Type Field ValueType TimeType
Salary Employee Salary Money CalendarPeriod

Wage Types

# Name ValueExpression Collector
100 Salary MyRegulation.GetSalary() —

Scripts

Script Function type File
CompositeWageTypeValueFunction WageTypeValue Scripts/CompositeWageTypeValueFunction.cs
WageTypeValueFunction WageTypeValue Scripts/WageTypeValueFunction.cs

Test Result — January 2023

Employee WT 100 Salary
Mario Nuñez 5 000

Key Design Decisions

Composite vs. Extension Method

The composite pattern wraps WageTypeValueFunction in a separate class rather than adding extension methods directly. This allows grouping multiple related methods under a named namespace (MyRegulation) and enables full IDE support — IntelliSense, refactoring, and debugger step-through — when developing regulation logic in Visual Studio.

Lazy initialization via ??=

MyRegulation => function ??= new(this) creates the composite instance on first access and reuses it for subsequent calls within the same wage type evaluation. This avoids repeated construction without requiring manual lifecycle management.

Reuse across derived regulations

Because the composite class is a plain C# type injected via constructor, higher-level regulations can subclass or wrap it — keeping shared calculation logic in the base regulation while country- or client-specific logic lives in derived layers.

Files

File Purpose
Payroll.json Tenant, regulation, case, wage type, script registrations
Scripts/CompositeWageTypeValueFunction.cs Business logic class (GetSalary)
Scripts/WageTypeValueFunction.cs Partial extension — registers MyRegulation property
Test.et.json Employee payroll test — January 2023, WT 100 = 5 000
Setup.pecmd Full setup: delete + import + set password
Delete.pecmd Remove the ExtendedTenant
Test.pecmd Run employee payroll test

Commands

# Full setup
Setup.pecmd

# Run test
Test.pecmd

# Teardown
Delete.pecmd

Web Application Login

Field Value
User lucy.smith@foo.com
Password @ayroll3nginE

See Also