Add hlint

README.md

@@ -76,6 +76,7 @@ Other dedicated linters that are built-in are:
 | [Flake8][13]                 | `flake8`       |
 | [Golangci-lint][16]          | `golangcilint` |
 | [hadolint][28]               | `hadolint`     |
+| [hlint][32]                  | `hlint`     |
 | [HTML Tidy][12]              | `tidy`         |
 | [Inko][17]                   | `inko`         |
 | [Languagetool][5]            | `languagetool` |
@@ -304,6 +305,7 @@ nvim --headless --noplugin -u tests/minimal.vim -c "PlenaryBustedDirectory tests
 [29]: https://github.com/stylelint/stylelint
 [30]: https://github.com/KDE/clazy
 [31]: https://github.com/Kampfkarren/selene
+[32]: https://github.com/ndmitchell/hlint
 [null-ls]: https://github.com/jose-elias-alvarez/null-ls.nvim
 [plenary]: https://github.com/nvim-lua/plenary.nvim
 [ansible-lint]: https://docs.ansible.com/lint.html

lua/lint/linters/hlint.lua

@@ -0,0 +1,26 @@
+local severities = {
+  error = vim.lsp.protocol.DiagnosticSeverity.Error,
+  warning = vim.lsp.protocol.DiagnosticSeverity.Warning,
+  suggestion = vim.lsp.protocol.DiagnosticSeverity.Hint,
+}
+
+return {
+  cmd = "hlint",
+  args = { "--json" },
+  parser = function(output)
+    local diagnostics = {}
+    local items = #output > 0 and vim.fn.json_decode(output) or {}
+    for _, item in ipairs(items) do
+      table.insert(diagnostics, {
+        range = {
+          ["start"] = { line = item.startLine, character = item.startColumn },
+          ["end"] = { line = item.endLine, character = item.endColumn },
+        },
+        severity = severities[item.severity:lower()],
+        source = "hlint",
+        message = item.hint,
+      })
+    end
+    return diagnostics
+  end,
+}

tests/hlint_spec.lua

@@ -0,0 +1,59 @@
+describe("linter.hlint", function()
+  it("can parse an error", function()
+    -- Main.hs
+    --
+    -- (first
+    --
+    -- hlint Main.hs --json
+    local parser = require("lint.linters.hlint").parser
+    local result = parser([[
+      [{"module":[],"decl":[],"severity":"Error","hint":"Parse error: possibly incorrect indentation or mismatched brackets","file":"Main.hs","startLine":2,"startColumn":1,"endLine":2,"endColumn":1,"from":"  (first\n> \n","to":null,"note":[],"refactorings":"[]"}]
+    ]])
+    assert.are.same(#result, 1)
+    local expected = {
+      range = {
+        ["start"] = {
+          character = 1,
+          line = 2,
+        },
+        ["end"] = {
+          character = 1,
+          line = 2,
+        },
+      },
+      severity = vim.lsp.protocol.DiagnosticSeverity.Error,
+      source = "hlint",
+      message = "Parse error: possibly incorrect indentation or mismatched brackets",
+    }
+    assert.are.same(result[1], expected)
+  end)
+
+  it("can parse a warning", function()
+    -- Main.hs
+    --
+    -- concat (map f x)
+    --
+    -- hlint Main.hs --json
+    local parser = require("lint.linters.hlint").parser
+    local result = parser([[
+      [{"module":["Main"],"decl":[],"severity":"Warning","hint":"Use concatMap","file":"Main.hs","startLine":1,"startColumn":1,"endLine":1,"endColumn":17,"from":"concat (map f x)","to":"concatMap f x","note":[],"refactorings":"[Replace {rtype = Expr, pos = SrcSpan {startLine = 1, startCol = 1, endLine = 1, endCol = 17}, subts = [(\"f\",SrcSpan {startLine = 1, startCol = 13, endLine = 1, endCol = 14}),(\"x\",SrcSpan {startLine = 1, startCol = 15, endLine = 1, endCol = 16})], orig = \"concatMap f x\"}]"}]
+    ]])
+    assert.are.same(#result, 1)
+    local expected = {
+      range = {
+        ["start"] = {
+          character = 1,
+          line = 1,
+        },
+        ["end"] = {
+          character = 17,
+          line = 1,
+        },
+      },
+      severity = vim.lsp.protocol.DiagnosticSeverity.Warning,
+      source = "hlint",
+      message = "Use concatMap",
+    }
+    assert.are.same(result[1], expected)
+  end)
+end)