{"path":"/sutl","content":{"title":"sUTL","summary":"A pure programming language for structured values: learn it, inspect examples, and follow the ideas behind it.","body":"![sUTL wordmark in black, with red square brackets and purple braces.](media:01a19b4c-e5a6-7670-a90d-32d9b283380f)\n\n**sUTL**—the sUTL Universal Transform Language, pronounced “subtle”—transforms structured values into other structured values. Its programs are values too: maps, lists, strings, numbers, booleans and null.\n\nThe host handles networking, storage and permissions. sUTL computes the value in the middle. Programs can be stored, passed between systems, generated and inspected with the same tools used for ordinary data.\n\n## Start here\n\n- [Why sUTL?](/sutl/why-sutl) — the motivation, portability and pure computation.\n- [MLSNBN](/sutl/mlsnbn) — the value model beneath JSON.\n- [Guide to sUTL](/sutl/guide) — seven chapters, from structural templates to reusable libraries.\n- [Worked examples](/sutl/examples) — source, transform and expected result together.\n\n## Use the language\n\n- [Language reference](/sutl/reference) — the current sUTL 1.0 contract and runtime limits.\n- [Core library](/sutl/core-library) — all 44 declarations and their dependencies.\n- [sUTL in Everything](/sutl/everything) — bounded programmable templates as a concrete use.\n\n## Ideas and history\n\n- [History and future directions](/sutl/history) — bOTL, Lisp, portable computation and proposed compilation work.\n- [Historical dialects](/sutl/guide/history) — how the old implementations differed and which decisions are now settled.\n\n## Install and experiment\n\nImplementations are available for [JavaScript](https://www.npmjs.com/package/sutl-js), [Python](https://pypi.org/project/sutl-py/) and [Go](https://pkg.go.dev/github.com/emlynoregan/sutl-go). The [language repository](https://github.com/emlynoregan/sutl-language) contains the normative specification and executable conformance corpus.\n\nThis collection contains readable articles and examples. The [interactive language site](https://sutl-bronzearch.house-of-ur.com/) retains its [playground](https://sutl-bronzearch.house-of-ur.com/playground/) and runnable examples.\n\n## The original sUTL identity\n\nThe original site used red square brackets and purple braces as its visual identity. These are the original recovered graphics, preserved here alongside the language and its documentation.\n\n![Original square sUTL logo: tilted red square brackets enclosed by purple braces.](media:01a19b4c-f985-77c4-86fd-06067f6b1513)\n\n[Back to sUTL](/sutl) · [Software & Agents](/topics/software-and-agents) · [All topics](/guide)","author":"Emlyn O'Regan","media":[{"asset_id":"01a19b4c-e5a6-7670-a90d-32d9b283380f","alt":"sUTL wordmark in black, with red square brackets and purple braces."},{"asset_id":"01a19b4c-f985-77c4-86fd-06067f6b1513","alt":"Original square sUTL logo: tilted red square brackets enclosed by purple braces."}],"hero":"01a19b4c-f985-77c4-86fd-06067f6b1513"}}