q-lint for VS Code
Linting, Quick Fixes and syntax colouring for q/kdb+, as you type, from the
q-lint language server.
Why another linter? I wasn't satisfied with the solutions available for
q, so I decided to build my own, inspired by the best practices of linters
for other languages, such as Ruff for Python.
Early version. Open source, built to be good enough for agentic
development, and already catching the most common problems. A finding that
looks wrong is worth an issue.
It never executes your code, which is why it is safe on every keystroke -
and why there is no completion, hover or go-to-definition.
Features
- Diagnostics for what q would refuse, plus likely mistakes and style
conventions, depending on the profile.
- Quick Fixes for 41 rules, among them operators and keywords
from other languages (
==, &&, +=, true, return), invalid string
escapes, symbols where q wants strings, f(a;b) calls, one-row tables,
dead code, unused locals, comparisons a where phrase groups wrongly, and
a nested lambda reading its parent's local.
Those that cannot change a working program also run in bulk with
qlinter --fix; --unsafe-fixes adds the rest.
- Syntax colouring from a TextMate grammar, plus semantic tokens: a
function is coloured wherever it is called, even when another
.q file in
the workspace defines it, and a parameter wherever its body reads it.
Unused parameters and locals are faded.
Requirements
None on macOS (Apple Silicon and Intel), Linux x64 or Windows x64: the
matching qlinter binary is bundled. Elsewhere, take one from
releases and put it on
PATH or in q-lint.serverPath.
Settings
| setting |
default |
|
q-lint.profile |
unset |
general: only what q refuses. style: also likely mistakes. styleq: also published style guides. uqf: also one repository's conventions. Unset, a repository's qlinter.toml decides, and style applies without one. |
q-lint.serverPath |
empty |
Your own binary. Empty uses the bundled one, then qlinter on PATH; set, it always wins. |
q-lint.trace.server |
off |
Log client-server traffic. |
Repository settings
A qlinter.toml at the repository root (or [tool.qlinter] in
pyproject.toml) sets the profile, the rules and the exclusions for every
file beneath it, the way Ruff's configuration does; editing it re-lints the
open files. See the configuration
docs.
Troubleshooting
Open Output → q-lint: the first line names the server version and binary,
and the server's errors land there. After replacing the binary, run
q-lint: Restart Server. On macOS, apps started from the Dock do not see
your shell's PATH, so give q-lint.serverPath an absolute path.
qlinter --rules lists every rule; qlinter --explain <CODE> explains one.
Development
server/qlinter is a checked-in darwin-arm64 build, so a clone packages
without a release build; releases bundle their own per platform. Refresh it
with cargo build --release && install -m 755 target/release/qlinter editors/vscode/server/qlinter. The grammar is generated:
python3 scripts/q_grammar.py > editors/vscode/syntaxes/q.tmLanguage.json.
