# Language Specification

This chapter defines the syntax of Decodal source and the rules that determine evaluation results.

- Syntax and grammar
- Primitives, objects, arrays, and functions
- Constraints, `Unknown`, and `default`
- `&`, `//`, `as`, and other operators
- Modules, imports, and lazy evaluation
- Materialization and diagnostics

See the [manual contents](../index.md) for the complete chapter list.