Rell Programming Language

Rell is the relational blockchain programming language for Chromia. It combines a SQL-like data model with a statically typed, imperative syntax, and compiles against a PostgreSQL-backed runtime.

The canonical repository is hosted on GitLab: gitlab.com/chromaway/rell. The GitHub repository is a read-only mirror — please file issues and merge requests on GitLab.

Links

• Documentation: https://docs.chromia.com/rell/rell-intro
• API reference: https://docs.chromia.com/pages/rell/index.html
• Release notes: https://gitlab.com/chromaway/rell/-/tree/dev/doc/release-notes
• Chromia documentation: https://docs.chromia.com/

Requirements

• Java 21
• Docker — for PostgreSQL and Testcontainers-based integration tests

Build

Command	Description
./gradlew assemble	Compile and package all JARs
./gradlew build	Assemble and run all tests (requires PostgreSQL and Docker)
./gradlew clean	Clean build outputs
./gradlew installRellDist	Install the Rell runtime to rell-tools/build/install/rell-dist/

Run

Try Rell with chr (latest release)

Install the Chromia development environment (or just the chr CLI) as described in: https://docs.chromia.com/get-started/installation

Then start the REPL from the latest released Rell via:

chr repl

This path uses the published release directly.

REPL

This command runs from your local checkout and may take longer because it builds the repo locally.

./work/rell.sh

Rell 0.16.0-SNAPSHOT
Type '\q' to quit or '\?' for help.
>>> 2+2
4
>>> range(10) @* {} (@sum $)
45
>>>

Execute a program

Create hello.rell:

module;

function main() {
    print('Hello, world!');
}

Run it (pass the parent directory of hello.rell via -d):

./work/rell.sh -d . hello main

Hello, world!