XPR — Cross-Language Expression Language

A sandboxed expression language with JS/Python-familiar syntax, designed for data pipeline transforms.

Repositories

Repo	Description
xpr-lang/xpr	Language specification and conformance tests (this repo)
xpr-lang/xpr-js	JavaScript/TypeScript runtime
xpr-lang/xpr-python	Python runtime
xpr-lang/xpr-go	Go runtime
xpr-lang/xpr-docs	Documentation site
xpr-lang/xpr-playground	Interactive playground

Spec

See XPR-SPEC.md for the complete language specification.

Conformance Tests

The conformance/ directory contains YAML test files organized by category:

• access.yaml — Property access, optional chaining
• arithmetic.yaml — Arithmetic operators, precedence, associativity
• collections.yaml — Array collection methods (v0.1)
• collections_v5.yaml — New array methods (v0.5): sortBy, take, drop, sum, avg, etc.
• comparison.yaml — Equality and comparison operators
• datetime.yaml — Date/time functions (v0.3)
• destructuring.yaml — Object and array destructuring (v0.4)
• examples.yaml — End-to-end integration examples
• features_v5.yaml — v0.5 features: math, type predicates, fromEntries, rest params
• functions.yaml — Built-in functions, custom functions, arrow functions
• let.yaml — Let bindings, scoping, shadowing, closures
• literals.yaml — Number, string, boolean, null, array, object, template literals
• logic.yaml — Logical operators, ternary, nullish coalescing
• math_v5.yaml — Math functions and constants (v0.5)
• methods_v2.yaml — v0.2 array, string, object methods and range()
• negative_indexing.yaml — Negative array indexing (v0.3)
• pipe.yaml — Pipe operator
• regex.yaml — Regex functions (v0.3): matches, match, matchAll, replacePattern
• regex_literals.yaml — Regex literal syntax and regex type (v0.4)
• spread.yaml — Array and object spread operator
• strings.yaml — String methods
• type_predicates.yaml — Type predicate functions (v0.5)

See conformance/SCHEMA.md for the test format specification.

Using Conformance Tests in Your Runtime

Add this repo as a git submodule:

git submodule add https://github.com/xpr-lang/xpr.git conformance

Then read all *.yaml files from the conformance/ directory in your test runner.

License

MIT