DimFort — Emacs companion

Emacs companion for DimFort — the dimensional-homogeneity checker for Fortran. Thin LSP client + commands; the heavy lifting is done by the dimfort lsp server.

Want a hands-on look first? See the DimFort tour — a short, self-contained Fortran file that exercises the most common diagnostics, with a line-by-line walkthrough.

Works with both eglot (built-in since Emacs 29) and lsp-mode (MELPA). Whichever you've loaded is the one DimFort registers with; loading both is harmless.

Requirements

• Emacs ≥ 29.1.
• DimFort installed and dimfort lsp reachable from exec-path (or set dimfort-executable to an absolute path). Install instructions: https://github.com/ArrialVictor/DimFort.

Installation

Until this is on MELPA, clone and add to your load-path:

git clone https://github.com/ArrialVictor/DimFort-EmacsCompanion.git \
  ~/.emacs.d/site-lisp/DimFort-EmacsCompanion

(add-to-list 'load-path "~/.emacs.d/site-lisp/DimFort-EmacsCompanion")
(require 'dimfort)
(dimfort-setup)

With use-package:

(use-package dimfort
  :load-path "~/.emacs.d/site-lisp/DimFort-EmacsCompanion"
  :hook ((f90-mode . dimfort-setup)
         (fortran-mode . dimfort-setup)))

After this, just open a Fortran file and start your LSP client of choice — M-x eglot or M-x lsp. DimFort attaches automatically.

Configuration

All variables live under M-x customize-group RET dimfort:

Variable	Default	Effect
dimfort-executable	"dimfort"	Path to the dimfort binary.
dimfort-inlay-hints-enabled	nil	Server emits inlay hints (off — redundant beside the panel/hover).
dimfort-completion-enabled	t	Server provides unit-name completion.
dimfort-code-actions-enabled	t	Server advertises code actions.
dimfort-goto-definition-enabled	t	Server answers textDocument/definition.
dimfort-hover	"short"	Hover verbosity: disabled / short / detailed. Defaults to short — a compact unit surface beside the panel.
dimfort-cache-mode	"read-write"	Content-hash check cache (off / read-only / read-write).
dimfort-cache-dir	""	Cache directory (empty = server default).
dimfort-scale-mode	"auto"	Scale checking (S001/S002): auto defers to dimfort.toml, on/off override. Cycle with dimfort-cycle-scale.
dimfort-max-workset-size	40	Cap on workset size.
dimfort-external-modules	nil	Modules treated as out-of-workset (silences U007).
dimfort-fortran-modes	(f90-mode fortran-mode)	Modes DimFort registers for.
dimfort-panel-enabled	t	Open the side panel automatically on attach (on — set nil to open on demand).
dimfort-panel-side	right	Panel dock side (right / left / bottom).
dimfort-panel-width	0.35	Panel width fraction (left/right docking).
dimfort-panel-debounce	0.2	Idle seconds before the panel cursor-follow refresh.
dimfort-show-cursor	t	Show the Cursor section (Expression / Diagnostics / Interactions / Actions).
dimfort-show-scope	t	Show the Scope section.
dimfort-show-imports	t	Show the Imports section.

Commands

Command	Effect
M-x dimfort-check-workspace	Run the workspace-wide unit check; refreshes the panel footer's Project: segment.
M-x dimfort-restart	Restart the language server.
M-x dimfort-status	Print current feature toggles in the echo area.
M-x dimfort-toggle-inlay-hints	Toggle inlay hints; restarts the server.
M-x dimfort-toggle-completion	Toggle unit-name completion; restarts.
M-x dimfort-toggle-code-actions	Toggle code actions; restarts.
M-x dimfort-toggle-goto-definition	Toggle go-to-definition; restarts.
M-x dimfort-cycle-hover	Cycle hover verbosity (disabled → short → detailed); restarts.
M-x dimfort-cycle-cache	Cycle the content-hash cache through off → read-only → read-write.
M-x dimfort-clear-cache	Delete the .dimfort-cache/ directory and restart the server.
M-x dimfort-open-config	Quick-pick between dimfort.toml (workspace config) and the project units file. Each opens if it exists, or creates a commented stub if not. When creating a units file: sub-pick Empty file or Reference template (bundled defaults, all commented out). Auto-wires [units].file = "units.toml" into dimfort.toml.
M-x dimfort-cycle-scale	Cycle scale checking (auto → on → off); auto defers to dimfort.toml.
M-x dimfort-cycle-coverage	Cycle coverage visualisation (disabled → gutter → background); companion-only, no LSP restart.
M-x dimfort-toggle-panel	Toggle the cursor-following side panel.
M-x dimfort-toggle-cursor	Show / hide the Cursor section (Expression / Diagnostics / Interactions / Actions).
M-x dimfort-toggle-scope	Show / hide the Scope section.
M-x dimfort-toggle-imports	Show / hide the Imports section.
M-x dimfort-scope-filter	Filter the panel's Scope section by name/unit (empty clears).
M-x dimfort-imports-filter	Filter the panel's Imports section by name/unit/module (empty clears).
M-x dimfort-cycle-sort-mode	Cycle the panel sort mode shared by Scope and Imports (line → alphabetic → status).
M-x dimfort-cycle-unit-display	Cycle the unit-display mode shared by Scope and Imports (input → canonical → both).
M-x dimfort-coverage-report	Open a buffer with the per-tier coverage breakdown (Verified / Unverified / Violation / Unparsed, for both file and project scope). Press q to close.

Side panel

A cursor-following side window rendering the six DimFort sections — Expression, Diagnostics, Interactions, Actions, Scope, Imports. The full description of what each section shows is the canonical side-panel reference; the controls below are the Emacs-specific bits.

Toggle: open by default on attach. M-x dimfort-panel-toggle opens or closes the persistent side window.

Settings:

• dimfort-panel-enabled — set to nil to keep the panel closed on attach.
• dimfort-panel-side / dimfort-panel-width — dock side and width.

Filters:

• M-x dimfort-scope-filter — narrow the Scope section to variables whose name or unit matches.
• M-x dimfort-imports-filter — same for Imports.

Navigation: press RET (or mouse-1) on any declaration, diagnostic, interaction-site, or import row to jump to it (cross-file for interaction sites and imports).

Coverage bar: a footer below the sections shows the active file's coverage percentage and tier counts on the left, and the whole-workspace aggregate on the right — File: 78% (🟡 18 🔴 2) Project: 12.9% (🟡 N 🔴 M). File-scope updates live on every edit; workspace-scope is populated when you run M-x dimfort-check-workspace. Pre-refresh the bar shows Project: –; during a refresh it shows a Braille spinner; once any buffer edits fire the Project numbers dim to signal they may no longer reflect current state. Requires DimFort 0.2.5+.

What you get

Same surface as the VSCode companion:

• Diagnostics (H001–H004, U001/U002/U005–U007/U010, …) in the buffer via flymake (eglot) or flycheck/lsp-ui (lsp-mode).
• Hover docs for variable units.
• Inlay hints, go-to-definition, completion, code actions (toggleable).
• Workspace-wide cross-file checks driven from use clauses.
• Coverage visualisation (requires DimFort 0.2.4+) — per-line status in one of two mutually-exclusive visual encodings:
  • Gutter — coloured fringe dot per line, in four tiers (green / yellow / red / blue).
  • Background — line tint behind the text in the same four tiers. Off by default; toggle with M-x dimfort-cycle-coverage. Customise the colours via the faces dimfort-coverage-green / dimfort-coverage-yellow / dimfort-coverage-red / dimfort-coverage-blue (fringe dots) and dimfort-coverage-bg-* (line tint).

Notes

• dimfort.insertSnippet (used by the "add @unit{}" code action) inserts the snippet literally; Emacs LSP clients don't expand ${1:placeholder} tab-stops, so they're flattened to default text and the cursor lands at the $0 position.

License

MIT.