Configure indentation by language

To use four spaces generally and two in Rust files, edit the existing [editor] table in ~/.config/rev/config.toml and add or update [language.rust]:

[editor]
indent_style = "spaces"
indent_width = 4

[language.rust]
indent_width = 2

Save the configuration and start a new session with rev main.rs. At the beginning of a line, Tab inserts two spaces. A new session opening notes.txt still inserts four.

The built-in .rs association selects rust; no extra association is needed. Other language settings inherit the global values unless explicitly changed.

For literal tabs instead, set the language's indent_style = "tabs". tab_width controls how wide existing tab characters appear. Neither option converts existing spaces or tabs. For an explicit conversion, mark a region and run M-x tabify or M-x untabify.

The language rules list the built-in filename associations and accepted overrides. For another configuration location, see startup configuration.