Getting Started with the IDL Expression Library
Introduction
When building integrations, data flows, or transformations, developers often encounter repetitive scripting needs. Instead of writing expressions from scratch each time, the IDL Expression Library provides a central collection of reusable snippets for common scenarios.
Think of it as your toolbox of ready-made expressions for string handling, control flow, transformations, and error handling.
Why Use IDL Expressions?
Handle edge cases: Many client and customer scenarios cannot be configured directly in the UI. IDL expressions bridge this gap by providing precise control over data transformations and business rules.
Save time: Avoid reinventing the wheel by reusing tested patterns.
Improve consistency: Standardized expressions reduce errors across projects.
Enable flexibility: Expressions are modular and can be combined for complex workflows.
Structure of an Expression
Each expression in the library follows a consistent format for clarity and reuse:
Name: A short, descriptive title
Category: e.g., Control Flow, String Handling, Transformation
Description: What the expression does
Syntax: The reusable IDL pattern
Example: Input/output illustration
Notes/Variations: Extensions or alternatives
Example Expressions
Here are a few samples from the library to help you get started:
🧩 1. Add First Letter of Middle Name
Category: String Handling
Use Case: Format names as FirstName M LastName
Syntax:
FirstName
|> string_concat(" ", string_left(MiddleName,1))
Example:
Input: FirstName = "Alex", MiddleName = "Michael", LastName = "Hall"
Output: Alex M Hall
📞 2. Send Home Phone & Business Email (If Home Phone Exists)
Category: Control Flow
Use Case: Output both Home Phone and Business Email only if Home Phone exists.
Syntax (simplified):
if is_material(HomePhone) {
HP*homePhone EM*businessEmail
} else {
omit()
}
Example Output:
PER*IP**HP*4166061234*EM*pr.ku@dayforce.com
📅 3. Latest Benefit Plan Date
Category: Control Flow
Use Case: Get the most recent Coverage Start Date from multiple benefit elections.
Syntax:
order_by_desc(EmployeeElections, e => e.CoverageStartDate)
|> map_single(e => e.CoverageStartDate)
Example:
Input Dates: 01-08-2025, 01-07-2025, 01-09-2025
Output: 01-09-2025
Key Takeaways
IDL Expressions are the building blocks of scripting in integrations.
They follow a standard structure (Name → Category → Description → Syntax → Example → Variations).
Common use cases include string formatting, conditional output, filtering, transformations, and calculations.
You can start small (e.g., cleaning postal codes) and scale up to more complex scenarios (e.g., filtering employees based on effective dates).
📖 Next Steps
This article introduces the basics of IDL expressions and provides sample use cases.
👉 For the full catalog of reusable expressions, including advanced variations and additional categories, check the files section of this article for an attached guide.
