Emacs, rust, jump to dependency

zeroexcuses · February 19, 2021, 3:01pm

I am considering switching from IntelliJ back to Emacs.

One of my favorite feature sin IntelliJ is that I can put the cursor over a function / struct of a dependency (i.e. code I did not write), and jump to it's definition. This involves IntelliJ unzipping the dependency sources somewhere and indexing it.

Question: is there a way to achieve this in Emacs? (If so, can you share relevant sections of ~/.emacs.d/init.el)

alice · February 19, 2021, 3:13pm

I know the vim rust-analyzer plugins claim to have this ability, though I don't really use it myself. Presumably whatever emacs uses is also communicating with rust-analyzer, so I'd assume it can do the same.

Edit: I just saw the part about dependencies. I have no idea on that part.

thor314 · February 19, 2021, 3:40pm

Yes, by default Racer binds this to M-., and rust-analyzer has a jump-to-def feature as well. My configuration, in case you need help getting started:

github.com

thor314/emacs/blob/main/config/lang/rust.org

* Rustic - lsp extensions to rust-mode
#+begin_src emacs-lisp
  (use-package rustic) ; lsp-compatible rust mode
(add-hook 'rust-mode-hook 'rustic-mode)
(add-hook 'rustic-mode-hook
  (lambda ()
    (setq rustic-lsp-server 'rust-analyzer) ; not rls
    (setq lsp-rust-analyzer-server-command '("~/.cargo/bin/rust-analyzer"))
                                        ;(setq rustic-format-on-save t) ; has annoying bug move point to other buffer bug
  (setq rustic-indent-offset 2)
    (setq rustic-match-angle-brackets nil)
    ;; thought this would be better, was wrong.
    ;(setq rustic-compile-display-method 'popwin:display-buffer-1) ; display if possible in popup-win
    ))
#+end_src
[[https://github.com/brotzeit/rustic][rustic]]. [[https://rust-analyzer.github.io/manual.html][rust-analyzer]].

* Cargo binds and .toml  mode font-lock
#+begin_src emacs-lisp
  (use-package cargo)

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and someone who's probably done it better than I:

JosephOsborn · February 19, 2021, 3:47pm

Just to add to @thor314 ’s great answer: xref-find-definitions (M-.) and xref-pop-mark-stack (M-, or “go back”) work in a broad variety of lsp and non-lsp modes (sometimes natively and sometimes via etags/gtags) and are excellent tools for navigating unfamiliar code in lots of languages.