Expression Language Template

What is Expression Language Template and what is it for?

Expression Language Template is a starter repository published by Coasys for building a new way to store and share data on AD4M networks. It exists so a developer can begin from working scaffolding — an expression language paired with its own Holochain DNA — instead of writing the plumbing from scratch.

The repository is one of four starter templates published alongside AD4M, the Coasys framework for building apps that share data across independent systems. AD4M's own documentation lists it as the "Expression Language with DNA" template, alongside versions without a DNA and the matching templates for link languages. Its README describes it as a basic template for storing and fetching expressions — the data objects an AD4M app creates — on a network.

In AD4M a language is the piece of code that decides how one kind of data is stored and how it is found again; the documentation compares it to a protocol or a storage adapter. Writing one means answering two questions: how do I put data somewhere and get an address back, and how do I turn that address back into the data. This template answers both in Deno-compatible JavaScript and adds a Holochain DNA so the storage can sit on a Holochain network.

A developer who wants a new kind of post, note or profile in an AD4M app can clone the template, rename it and replace the storage logic with their own, then publish it so other AD4M instances can install it. The documentation's Languages page sets out the module contract the template follows, and its developer guide goes further. hAppRadar records the repository as inactive since early 2024, so it reads best as a historical starting point.

From 2 public sources, checked 23 September 2026.