HTMLlike

HTMLlike is a markup language designed to structure documents in a way that mirrors HTML while introducing a stricter grammar and extensibility features. It exists in a hypothetical specification used in certain development and education environments to illustrate formal parsing and validation. The language aims to be human-readable and machine-parseable, with predictable rendering and easier tooling.

HTMLlike uses tags enclosed in angle brackets and requires explicit opening and closing tags for all elements. Attribute values must be quoted with double quotes, and tag names are case-sensitive. Self-closing tags are allowed for empty elements and are written as <tag/>. The language enforces a single root element and a well-formed document structure, which simplifies static analysis and error detection. Namespaces can be declared with an xmlns-like attribute, enabling modular composition of documents.

Semantics in HTMLlike are defined through a set of standard tags such as article, section, and header, with additional support for user-defined elements via a formal extension mechanism. Styles and interactivity are provided by separate layers, keeping content markup separate from presentation. Data attributes (for example data-role or data-variant) offer a controlled way to attach metadata without altering rendering.

Tooling for HTMLlike includes validators, linters, and transpilers that can translate HTMLlike documents to other formats, including HTML for compatibility with existing renderers. Adoption remains niche and largely educational, but some projects use it to teach formal grammar, strict document design, and predictable tooling workflows.

History and status: The language originated in the HTMLlike Initiative in the mid-2010s as a didactic alternative to HTML. It has not displaced HTML in mainstream web use, but it remains a reference model for discussions about markup design and compiler-friendly document formats.