DimFort

VSCode client for DimFort — the dimensional-homogeneity checker for Fortran. Thin Language Server Protocol client: spawns dimfort lsp and forwards your Fortran sources to it; the server publishes diagnostics back, and VSCode renders them as squiggles and entries in the Problems panel.

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.

Install

1. Install DimFort itself

The extension needs the dimfort binary on PATH. Install with pipx (recommended on Homebrew Python / modern Linux distros where PEP 668 blocks pip install):

pipx install 'dimfort[lsp]'
dimfort --version

2. Install the extension

VSCode — from the Extensions panel, search "DimFort" and click Install. Or from the command palette (Cmd/Ctrl+P):

ext install arrialvictor.dimfort-vscode

VSCodium / Cursor / Theia / code-server — from the Open VSX gallery. Most of these clients have Open VSX as the default gallery; search "DimFort" in the Extensions panel:

ext install dimfort.dimfort-vscode

From .vsix (any client) — for offline / air-gapped installs or when a marketplace isn't reachable:

curl -L -o dimfort-vscode.vsix \
  https://github.com/ArrialVictor/DimFort-VSCompanion/releases/latest/download/dimfort-vscode.vsix
code --install-extension dimfort-vscode.vsix

Open any .f90 file — DimFort lights up. Settings → search dimfort to see toggle commands.

Features beyond plain diagnostics

• Hover — one setting, DimFort: Hover (dimfort.hover), picks the level of detail and applies to every hover surface: disabled (no hover — the side panel is the unit surface), short, or detailed.

  • On a call (function or subroutine) — same tree layout as the side panel: root row name(args) : ret with the overall verdict marker, and one child row per actual argument labelled by the source expression, with (expected <formal>) on a mismatch. Subroutines have no return unit so the root reads name(args) : ? and paints 🟡. Detailed adds a sub-tree under any computed actual showing how its unit was derived.
  • On an expression — Short is a one-line homogeneity check on assignments and relational expressions, a bare name : unit hover on identifiers, and the resolved unit on computed sub-expressions. Detailed is the full unit-algebra tree (every node tagged with its resolved unit and a per-row 🟢/🟡/🔴 marker that pinpoints where a violation fires or a leaf is unannotated). The header marker aggregates the worst row: 🔴 mismatch, 🟡 partial, 🟢 clean. Cycle the level with DimFort: Cycle Hover Verbosity; the side panel is unaffected (always detailed). The full layout spec lives in DimFort's hover-ui.md.
  

• Extract literal to a named PARAMETER quick-fix on H010 D1.5 warnings (the 1. + speed regularisation pattern). Press Cmd+. on the yellow squiggle, type a name in the input box, and the refactor inserts a typed PARAMETER declaration and rewrites the literal use site.

• Add @unit{} quick-fix on undeclared symbols.

• Inlay hints show ghost-text units inline next to each variable reference (toggle with DimFort: Toggle Inlay Hints).

• Go-to-definition on variables and procedure calls.

• Completion inside @unit{} annotations, sourced from the active unit table.

• Coverage visualisation — per-line status in one of two visual encodings (mutually exclusive). Off by default; toggle with DimFort: Cycle Coverage Visualisation (Disabled → Gutter → Background):

  • Gutter — one dot per line in the left margin, in four tiers: green (verified), yellow (needs attention), red (hard fire), blue (unparsed). Lines with no unit semantics (control flow, blank lines, string assignments) carry no dot.
  • Background — low-alpha background tint behind each in-scope line, in the same four tiers. Heavier visual weight; reads at a glance without scanning the gutter column.

Configuration

Settings (under DimFort in the Settings UI):

• dimfort.executable — path to the dimfort binary. Default is just dimfort (must be on $PATH). Override if the binary lives in a virtualenv: /path/to/.venv/bin/dimfort.
• dimfort.trace.server — set to verbose to see every LSP message in Output → DimFort. Useful for debugging.
• dimfort.inlayHints.enabled, dimfort.completion.enabled, dimfort.codeActions.enabled, dimfort.gotoDefinition.enabled — per-feature toggles. The palette also exposes them as DimFort: Toggle … commands.
• dimfort.hover — hover verbosity: disabled / short / detailed (default short). Cycle with DimFort: Cycle Hover Verbosity. The side panel is unaffected — it is always detailed. The server reloads automatically when any dimfort.* setting changes.
• dimfort.maxWorksetSize — cap on the number of files in a single check pipeline (default 40). Restart the language server after changing.
• dimfort.externalModules — extra module names treated as external (no U007 diagnostic when they're missing from the workspace). Extends the built-in allowlist.
• dimfort.cache.mode — content-hash cache for the workspace check: read-write (default), read-only, or off. With read-write, warm re-runs replay cached diagnostics for files whose source, includes, and dependencies haven't changed (a benchmark workspace measured ~33 s cold → ~20 s warm). Palette command DimFort: Cycle Content-Hash Cache (Off / Read-only / Read-write) cycles all three modes. Invalidation triggers and the design are documented in DimFort/docs/usage.md#content-hash-cache.
• dimfort.cache.dir — optional override for the cache directory. Empty (default) means .dimfort-cache/ under the first workspace folder.
• dimfort.scale.mode — opt-in scale/magnitude checking (S001 multiplicative, S002 affine-offset): auto (default — defer to the project dimfort.toml [scale] enabled), on, or off. on/off override the toml for the editor session. Cycle with DimFort: Cycle Scale Checking.
• dimfort.panel.enabled — reveal the side panel on activation (default true — set this false to keep it closed and open it yourself from the DimFort activity-bar icon). dimfort.panel.debounceMs tunes its cursor-follow refresh.

Default stance: the side panel is on and hover defaults to short — both cursor-following unit surfaces. Inlay hints default off (redundant beside the panel/hover) and the cache defaults to read-write. Adjust any of these in Settings.

Side panel

A cursor-following side panel 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 VSCode-specific bits.

Toggle: open by default. The DimFort activity-bar icon toggles the panel; the palette command DimFort: Show Side Panel does the same.

Settings:

• dimfort.panel.enabled — set to false to keep the panel closed on attach.

Filters: the Scope and Imports sections each carry an inline filter box (name / unit / module).

Restoring panel layout: each view (Cursor / Scope / Imports) can be independently dragged to the bottom panel or secondary sidebar, collapsed, or hidden via right-click on its title bar. If you drag a view out and can't get it back via right-click menus, run the command palette View: Reset View Locations — it restores all DimFort views (and every other extension's views) to their default positions. The "+ Add View" affordance only re-adds hidden views, not views moved to another location, so dragged-out views need either a manual drag back or the reset command.

Commands

All commands are available from the Command Palette (Cmd/Ctrl+Shift+P) under the DimFort: category. Settings live under the dimfort.* namespace.

The full cross-companion mapping (which Nvim / Emacs command each row corresponds to) lives in DimFort's docs: see editor-integration/commands.md.

Develop locally

If you want to contribute or run from source rather than the marketplace build:

git clone https://github.com/ArrialVictor/DimFort-VSCompanion.git
cd DimFort-VSCompanion
npm install
npm run compile

Then open the folder in VSCode and press F5 — a second window launches with your local build of the extension.

Packaging a .vsix

Requires Node ≥ 20.18 (older Node breaks @vscode/vsce's undici transitive dependency). On macOS:

brew install node@20
export PATH="/opt/homebrew/opt/node@20/bin:$PATH"

Then:

npm install --save-dev @vscode/vsce
npm run compile
npx vsce package --allow-missing-repository

You'll get a dimfort-vscode-<version>.vsix. Install with code --install-extension dimfort-vscode-<version>.vsix.

License

MIT.