@jsonic/expr is a plugin that extends the Jsonic parser with a Pratt‑style expression language, supporting infix, prefix, suffix, ternary and parenthesized operators whose precedence can be customized. It compiles expressions into Lisp‑style S‑expression trees that developers can evaluate with their own logic, and it’s available for both TypeScript/Node.js and Go. The library is aimed at developers who need a lightweight, configurable expression parser to embed in web, server‑side, or CLI applications.