--- title: Topiary: Formatting Forests | daily.dev description: Topiary, a multi-language code formatter built on Tree-sitter, now supports Language Injections — the ability to format embedded languages within host... canonical: https://daily.dev/posts/topiary-formatting-forests-a2qg3hip8 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Topiary: Formatting Forests | daily.dev og:description: Topiary, a multi-language code formatter built on Tree-sitter, now supports Language Injections — the ability to format embedded languages within host... og:url: https://daily.dev/posts/topiary-formatting-forests-a2qg3hip8 og:image: https://api.daily.dev/og/posts/A2qg3Hip8.png og:image:alt: Topiary: Formatting Forests og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Topiary: Formatting Forests **[Planet Haskell](https://daily.dev/sources/phaskell)** · 10 min read · 0 upvotes · 0 comments ## Summary Topiary, a multi-language code formatter built on Tree-sitter, now supports Language Injections — the ability to format embedded languages within host documents. For example, OCaml code inside OCamllex files, or fenced code blocks in Markdown, are now formatted correctly and recursively. The feature works by running injection queries against the host AST to discover embedded spans, treating them as leaves during host formatting, then delegating each span to the appropriate inner language formatter. A LanguageResolver hook (using Arc for caching) ensures grammars are compiled only once per language, keeping performance sublinear in the number of injections. Known limitations include stateless formatting (cross-fence fragments can't share layout context) and grammars that require full source files. The feature is available now via Nix and will ship in an upcoming release. ## Full article daily.dev links to this article rather than hosting it. 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