Harper for Vale

A Vale style ported from Harper, Automattic's grammar checker.

Harper keeps its rules in three places: a small DSL, a body of Rust linters, and a tagged dictionary. This repository reads all three, compiles what it can into Vale checks, and writes the rest by hand. make measure scores the result against Harper itself.

I have went to the store for first time.
One was better then the other, and its wheels were fine.
We are better of with a GUI interface.

 1:8   warning  Use the past participle after a form of `have`.        Harper.SimplePastToPastParticiple
 1:26  warning  This construction requires 'the' before the ordinal.   Harper.ForTheNthTime
 2:16  warning  Use `than` for comparisons.                            Harper.ThenThan
 3:8   error    This phrase uses the word `off`.                       Harper.BetterOffWith
 3:25  warning  The acronym's last letter already stands for the       Harper.RedundantAcronyms
                last word.

Every rule that can offer a fix carries one, as the Action on each alert. Editors and the language server turn those into corrections you accept in place; on the command line they arrive in vale --output=JSON.

Measured against Harper v2.7.0 over 652 KB of Harper's own test sentences:

One linter can need several rules: a sequence matches a fixed number of tokens, so a linter accepting phrases of several lengths becomes a numbered family. Spell checking is not ported.

make measure prints the score, so you can check it. DIFFERENCES.md is where the gap is accounted for, and BENCHMARKS.md is what it costs to run.

Needs Vale v3.16.0 or newer: this style uses matchcase, its part-of-speech rules name a tagger with model, and v3.16.0 fixes the Hunspell affix continuation classes the dictionary depends on.

It ships as a Vale package. Name it in .vale.ini or _vale.ini, then run vale sync:

StylesPath = styles
MinAlertLevel = suggestion

Packages = https://github.com/vale-cli/Harper/releases/latest/download/Harper.zip

[*.{md,txt}]
BasedOnStyles = Harper

The URL is spelled out because Vale resolves a bare package name against its own library, which this style is not in. …/releases/download/TAG/ pins a release, and a path like dist/Harper.zip reads a local archive.

Install it as a package rather than by hand: the part-of-speech rules need the tagger dictionary the package carries in styles/config/dictionaries/, and copying the rule files alone leaves them quietly matching nothing.

Everything except Harper/ is generated and gitignored; make generate rebuilds it. The generators skip any name already in Harper/: a rule is hand-written precisely when the generated one was wrong, so it has to survive regeneration.

Severity comes from Harper's rule kind, which Vale requires and Harper does not express: outright mistakes are errors, likely mistakes warnings, matters of taste suggestions.

Everything is built against one pinned Harper release, v2.7.0. A rule read from one version and measured against another is measured against the wrong thing, so make refuses to run at a different tag.

git clone --branch v2.7.0 https://github.com/Automattic/harper ../harper-upstream
cargo build --release -p harper-cli --manifest-path ../harper-upstream/Cargo.toml

make package        # generate the rules, then build dist/Harper.zip

Not ../harper: this repository is Harper/, and on a case-insensitive filesystem (macOS by default) ../harper resolves back to it. HARPER= overrides the location.

harper-cli is needed because dictionary.dict holds base forms and affix flags, and Harper applies the affixes itself. Read raw, it gives base forms tagged as if they were the only forms — running as a bare verb — which is worse than no dictionary at all, since it overwrites what the model knew.

Apache License 2.0 — see LICENSE.

The rules are derived from Harper, Copyright (c) Automattic, Inc. and contributors, also under Apache 2.0. The matched phrases, corrections and messages are Harper's work; NOTICE records that and what this port changed.