Overview

Starlark is an untyped dynamic language with high-level data types, first-class functions with lexical scope, and automatic memory management or garbage collection.

Starlark is strongly influenced by Python, and is almost a subset of that language. In particular, its data types and syntax for statements and expressions will be very familiar to any Python programmer. However, Starlark is intended not for writing applications but for expressing configuration: its programs are short-lived and have no external side effects and their main result is structured data or side effects on the host application. As a result, Starlark has no need for classes, exceptions, reflection, concurrency, and other such features of Python.

Starlark execution is deterministic: all functions and operators in the core language produce the same execution each time the program is run; there are no sources of random numbers, clocks, or unspecified iterators. This makes Starlark suitable for use in applications where reproducibility is paramount, such as build tools.