# Expression

This chapter classifies the expressions evaluated by the language.

An expression is the basic unit for representing a value, constraint, structure, or computation.

```text
Expr
├─ literal
├─ identifier
├─ path reference
├─ object
├─ map constraint
├─ array
├─ array constraint
├─ function
├─ function call
├─ let
├─ match
├─ import
├─ composition
├─ range refinement (`as`)
└─ default
```

Links to each expression specification are collected in the [manual contents](../../index.md).