Tree-sitter text objects

Brackets and quotes are only the beginning. When Helix knows the language of a file, it parses it with tree-sitter, and match mode gains text objects that describe code rather than characters:

• f — a function
• t — a type (a struct, enum, class, …)
• a — an argument or parameter
• c — a comment

They work exactly like the pairs: mif selects a function’s body, maf selects the whole function including its signature. The same letters also move you between objects — ]f selects the next function, [f the previous one, and the same goes for ]a, [t and the rest.

This sandbox opens every exercise as plain text, so Helix doesn’t know the buffer is Rust yet. Tell it with a command: type :lang rust and press Enter. The syntax lights up, and the tree-sitter objects come alive. Helix normally does this for you from the file extension.

Try it in the editor. Work through the checklist below to move around by function.