Code Navigation

fsharp-ts-mode provides tree-sitter-powered navigation commands that use standard Emacs keybindings. If you're familiar with navigating code in other Emacs modes, the same keys work here -- but backed by tree-sitter's structural understanding of F#.

Definition Navigation

Jump between top-level definitions (let bindings, type definitions, member definitions, module declarations):

Key	Command	Description
C-M-a	beginning-of-defun	Jump to the start of the current/previous definition
C-M-e	end-of-defun	Jump to the end of the current definition

These are useful for quickly moving through a file by function or type. Press C-M-a repeatedly to step backward through definitions.

Sexp Navigation

Move over balanced expressions -- parenthesized groups, bracket expressions, or other syntactic units:

Key	Command	Description
C-M-f	forward-sexp	Move forward over the next balanced expression
C-M-b	backward-sexp	Move backward over the previous balanced expression

fsharp-ts-mode uses a hybrid approach: tree-sitter for structural navigation and the syntax table for delimiter matching (parentheses, brackets, braces). This handles both code-level and delimiter-level movement.

File Toggle

Key	Command	Description
C-c C-a	ff-find-other-file	Switch between .fs and .fsi

Toggles between implementation (.fs) and signature (.fsi) files. Useful when you're working on a module's public API alongside its implementation. The search patterns are configured via fsharp-ts-other-file-alist.

Imenu (Symbol Index)

Imenu is Emacs's built-in facility for jumping to definitions by name. fsharp-ts-mode generates fully-qualified names, so func inside MyModule appears as MyModule.func.

Imenu categories:

• Namespace -- namespace declarations
• Module -- module declarations
• Type -- type definitions (classes, records, unions, interfaces)
• Case -- union and enum cases
• Exception -- exception declarations
• Value -- let bindings at module level
• Member -- class/type members

Use M-x imenu to jump to a symbol, or use a completion framework like consult (M-x consult-imenu) for a searchable list.

Outline Mode (Emacs 30+)

fsharp-ts-mode integrates with outline-minor-mode for code folding. This lets you collapse and expand definitions to get an overview of a file's structure:

(add-hook 'fsharp-ts-mode-hook #'outline-minor-mode)

Fold/unfold with the standard outline keybindings (under C-c @), or use M-x outline-cycle for interactive toggling.

which-func-mode

Shows the name of the current definition in the mode-line (the status bar at the bottom of each window):

(add-hook 'fsharp-ts-mode-hook #'which-func-mode)

See also: Configuration for customizing font-lock and indentation behavior.