ATLHelper

struct ATLHelper<BodyExpression> where BodyExpression : ATLExpression

Overview

ATL helpers extend the OCL standard library with custom operations that can be reused across transformation rules and other helpers. They support both contextual helpers (associated with a specific type) and contextual-free helpers (global functions).

Overview

Helpers in ATL serve multiple purposes:

• Code reuse: Complex expressions can be encapsulated and reused

• Type extension: New operations can be added to existing types

• Modularity: Complex transformations can be broken down into manageable functions

• Testing: Individual helper functions can be tested independently

Example Usage

// Contextual helper for Family!Member
let familyNameHelper = ATLHelper(
    name: "familyName",
    contextType: "Families!Member",
    returnType: "String",
    parameters: [],
    body: navigationExpression
)

// Context-free helper
let utilityHelper = ATLHelper(
    name: "formatName",
    contextType: nil,
    returnType: "String",
    parameters: [firstNameParam, lastNameParam],
    body: concatenationExpression
)