Template::Stencil Offers Zero-Allocation Perl Rendering via Bytecode and C Interpreter

Template::Stencil is a new Perl template engine designed for high performance by parsing templates once into packed bytecode stored in a single memory arena. Unlike conventional engines that re-process templates on every request, it uses a threaded C interpreter to write output directly into a reusable buffer, achieving zero heap allocation and no system calls at steady state. The engine uses a unified {% %} delimiter syntax supporting variables, dotted paths, array indexing, loops, and filter chains, with HTML auto-escaping enabled by default. Built-in filters — including upper, lower, trim, html, uri, default, and fmt — are all implemented in C, while developers can also register custom filter coderefs. Template validation occurs at compile time, catching errors such as invalid filter names or malformed format strings before rendering begins.