chore: add treefmt formatting (nix fmt + pre-commit + CI check)#6
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Pull request overview
This PR pilots an ecosystem-wide formatting setup by integrating treefmt (via treefmt-nix) into the flake, wiring nix fmt as the unified formatter entrypoint, and enforcing formatting via a content-based check in CI (plus an installed pre-commit hook in the dev shell).
Changes:
- Add
treefmt.nixconfiguration and exposeformatter/checks.formattingfrom the flake. - Add CI “Format check” step (
nix fmt && git diff --exit-code) and document formatting/linting commands. - Apply an initial formatting pass across PureScript and Lua (FFI) sources and configs.
Reviewed changes
Copilot reviewed 11 out of 14 changed files in this pull request and generated 1 comment.
Show a summary per file
| File | Description |
|---|---|
treefmt.nix |
Defines tree-wide formatting rules (nixfmt, dhall, purs-tidy, lua-format) and excludes generated/vendor directories. |
flake.nix |
Adds treefmt-nix, exposes formatter + formatting check, and installs a pre-commit hook from the dev shell. |
flake.lock |
Locks the new treefmt-nix input. |
.github/workflows/ci.yml |
Adds a content-based formatting verification step in CI. |
AGENTS.md |
Documents the new nix fmt workflow and updated luacheck line-length setting. |
.tidyrc.json |
Adds purs-tidy configuration for PureScript formatting. |
.lua-format |
Adds LuaFormatter configuration for FFI formatting. |
.gitignore |
Ensures the new dotfiles are tracked despite the broad dotfile ignore rule. |
spago.dhall |
Formatting cleanup (whitespace). |
src/Effect/Uncurried.purs |
PureScript formatting (layout/line breaks) for readability and consistency. |
src/Effect/Uncurried.lua |
Lua FFI formatting (compact style consistent with formatter config). |
src/Effect.purs |
PureScript formatting adjustments (exports + foreign import layout). |
src/Effect.lua |
Lua formatting (compact style). |
test/regression/uncurried.lua |
Test formatting adjustments. |
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Wire treefmt via treefmt-nix: nixfmt, dhall format, purs-tidy (.tidyrc.json) and LuaFormatter for the FFI (.lua-format, kept over StyLua because it preserves the parentheses pslua's parser needs). `nix fmt` formats; the dev shell installs a content-based pre-commit hook and CI runs `nix fmt && git diff --exit-code` (content-based, since the in-place formatters bump mtime and would trip treefmt --fail-on-change). Lua lines budget 130 cols, matching the raised `luacheck --max-line-length`. The bulk of the diff is the first format pass.
This was referenced Jun 14, 2026
chore: add treefmt formatting (nix fmt + pre-commit + CI check)
purescript-lua/purescript-lua-lazy#4
Merged
chore: add treefmt formatting (nix fmt + pre-commit + CI check)
purescript-lua/purescript-lua-refs#5
Merged
Merged
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Pilot of the ecosystem formatting setup (ADR 0007). Wires treefmt via treefmt-nix and formats the tree.
Tooling.
treefmt.nixruns nixfmt,dhall format, purs-tidy (.tidyrc.json) and LuaFormatter (.lua-format). LuaFormatter is kept over StyLua because it preserves the parentheses pslua's foreign-file parser requires; the FFI keeps its compact one-line style with a 130-column budget, matching the raisedluacheck --max-line-length 130.Wiring.
nix fmtformats; the flake exposeschecks.formatting; the dev shell installs a pre-commit hook; CI gains a format-check step. The check is content-based (nix fmt && git diff --exit-code) rather thantreefmt --ci, because the in-place formatters bump mtime even when content is unchanged, which trips treefmt's--fail-on-change.Diff. Most of the changes are the first format pass over
*.pursand the*.luaFFI. Verified locally: build, regression test,luacheck --max-line-length 130, and the content-based format check all pass.This is the template for rolling the same setup across the other forks + compiler.