Protocol extensions for Eglot

Eglot supports (a subset of) the Language Server Protocol. However, there are useful protocol extensions that are not (yet) part of the official protocol specification. Eglot-x adds support for some of them.

Add the following line to your init file to enable eglot-x

    (with-eval-after-load 'eglot (require 'eglot-x))

To adjust which extensions are enabled:

    M-x customize-group RET eglot-x RET

Supported extensions

Files extension

The extension allows the client and the server to have separate file systems. For example, the server can run inside a Docker container, or the source code can be on a remote system accessed by Tramp. The client can send files to the server only from the result of project-files. The list of eligible files can further limited by eglot-x-files-visible-regexp and eglot-x-files-hidden-regexp. This feature works if project-roots and project-external-roots are set correctly.

Enabling extension disables Eglot's built-in support for Tramp files.

Additional reference methods

The command `eglot-x-find-refs' is the entry point for the extra methods. You can bind it to a key:

    (define-key eglot-mode-map (kbd "s-.") #'eglot-x-find-refs)

Currently, the ccls and rust-analyzer are the only servers whose extra reference methods eglot-x supports.

Encoding negotiation

The extension allows the client and the server to negotiate a proper encoding to be used in transmitting column positions.

rust-analyzer extensions

experimental extensions

Snippet TextEdits: see variable eglot-x-enable-snippet-text-edit.
Join Lines: see defun eglot-x-join-lines.
Move Item: see defun eglot-x-move-item-down and eglot-x-move-item-up.
On Enter: see defun eglot-x-on-enter.
Matching Brace: see eglot-x-matching-brace. However, emacs' own backward-sexp, and forward-sexp seem to be more useful.
Open External Documentation: see defun eglot-x-open-external-documentation.
Structural Search Replace (SSR): see defun eglot-x-structural-search-replace.

The server checks the correctness of the query while you type:

The replacement process is similar to query-replace:
Workspace Symbols Filtering: see defun eglot-x-find-workspace-symbol.

The xref buffer shows the current matches while the user iteratively types the query and another buffer shows the location of the first match.

Additional input refines the results and the point in main.rs is changed once again to the location of the new first result:

You can change the search scope and kind with C-l and C-M-l, respectively. See variable eglot-x-ws-keymap. The non-default settings are shown between braces:

Currently, the xref buffer shows the first lines of the matches. This is not always helpful.
Runnables: see defun eglot-x-ask-runnables.

Results for the whole buffer:

Selecting the first "runnable":

The "runnable" is executed as a compile-command:
Server Status: see variable eglot-x-enable-server-status. The mode-line displays the status unless it is "permanently OK".
Inlay Hints: for an initial, basic support see defun eglot-x-insert-inlay-hint-at-point.

rust-analyzer specific extensions

Expand Macro: see defun eglot-x-expand-macro.
Related Tests: see defun eglot-x-ask-related-tests.
Reload Workspace: see defun eglot-x-reload-workspace.
View Crate Graph: see variable eglot-x-graph-type and defun eglot-x-view-crate-graph.

You can also jump to the crate (Cargo.toml) if the graph-type is not 'svg':