constellation-lang Reference

constellation-lang is a domain-specific language for defining data transformation pipelines. It provides a declarative syntax with strong typing, type algebra, and field projections.

Learning Path

If you are new to constellation-lang, start with Pipeline Structure, then explore Types and Declarations. The orchestration features build on these fundamentals.

Table of Contents

Core Language

• Pipeline Structure - Overall pipeline organization
• Types - Primitive, record, union, optional, and parameterized types
• Declarations - Type definitions, inputs, assignments, outputs
  • Input Annotations - @example for input metadata
• Expressions - Variables, function calls, projections, conditionals
• Type Algebra - Merging types with the + operator
• Comments - Line comments syntax

Orchestration

• Orchestration Algebra - Boolean algebra for control flow
• Guard Expressions - Conditional execution with when
• Coalesce Operator - Fallback values with ??
• Lambda Expressions - Inline functions for higher-order operations

Module Call Options

• Module Options Reference - Complete guide to with clause options
  • Resilience Options - retry, timeout, delay, backoff, fallback
  • Caching Options - cache, cache_backend
  • Rate Control Options - throttle, concurrency
  • Advanced Options - on_error, lazy, priority
• Resilient Pipelines Guide - Real-world patterns

Module Options for Production

When building production pipelines, explore the Module Options Reference for resilience features like retry, timeout, and caching that make your pipelines robust.

Reference

• Examples - Complete example pipelines
• Error Messages - Understanding compiler errors