Add a generic makeprg/errorformat compiler linter

README.md

@@ -23,11 +23,6 @@ implementation or where the diagnostics reporting of the language server is
 inadequate and a better standalone linter exists.
 
 
-## TODO
-
-- [ ] Include more linters for languages with a lack of good language servers
-
-
 ## Installation
 
 - Requires [Neovim HEAD/nightly][2]
@@ -59,22 +54,31 @@ example on the `InsertLeave` or `TextChanged` events.
 
 ## Available Linters
 
-- [Languagetool][5]
-- [Vale][8]
-- [ShellCheck][10]
-- [Mypy][11]
-- [HTML Tidy][12]
-- [Flake8][13]
-- [Revive][14]
-- [Pylint][15]
-- [Golangci-lint][16]
-- Ruby
-- [Inko][17]
+There is a generic linter called `compiler` that uses the `makeprg` and
+`errorformat` options of the current buffer.
+
+Other dedicated linters that are built-in are:
+
+
+| Tool                | Linter name     |
+| ----                | -----------     |
+| Set via `makeprg`   | `compiler`      |
+| [Languagetool][5]   | `languagetool`  |
+| [Vale][8]           | `vale`          |
+| [ShellCheck][10]    | `shellcheck`    |
+| [Mypy][11]          | `mypy`          |
+| [HTML Tidy][12]     | `tidy`          |
+| [Flake8][13]        | `mypy`          |
+| [Revive][14]        | `revive`        |
+| [Pylint][15]        | `pylint`        |
+| [Golangci-lint][16] | `golangci-lint` |
+| Ruby                | `ruby`          |
+| [Inko][17]          | `inko`          |
 
 
 ## Custom Linters
 
-You could register custom linters by adding them to the `linters` table, but
+You can register custom linters by adding them to the `linters` table, but
 please consider contributing a linter if it is missing.
 
 
@@ -89,14 +93,42 @@ require('lint').linters.your_linter_name = {
 }
 ```
 
+Instead of declaring the linter as a table, you can also declare it as a
+function which returns the linter table in case you want to dynamically
+generate some of the properties.
+
 `your_parse_function` can be a function which takes two arguments:
 
 - `output`
 - `bufnr`
 
 
 The `output` is the output generated by the linter command.
-The function must return a list of diagnostics as specified in the [language server protocol][9]:
+The function must return a list of diagnostics as specified in the [language server protocol][9].
+
+You can generate a parse function from a Lua pattern or from an `errorformat`
+using the function in the `lint.parser` module:
+
+### from_errorformat
+
+```lua
+parser = require('lint.parser').from_errorformat(errorformat)
+```
+
+The function takes a single argument which is the `errorformat`.
+
+
+### from_pattern
+
+```lua
+parser = require('lint.parser').from_pattern(pattern, skeleton)
+```
+
+The function takes two arguments. The first is a lua pattern that must match
+four groups in order: line number, offset, code and message.
+
+The second argument is a skeleton used to create each diagnostic. This can be
+used to provide default values - for example to set a `severity`.
 
 
 <details>

lua/lint.lua

@@ -63,8 +63,21 @@ local function read_output(bufnr, parser, client_id)
 end
 
 
-function M.try_lint()
-  local linters = resolve_linters()
+function M.try_lint(names)
+  if type(names) == "string" then
+    names = { names }
+  end
+  local linters
+  if names then
+    linters = vim.tbl_map(
+      function(name)
+        return assert(M.linters[name], 'Linter with name `' .. name .. '` not available')
+      end,
+      names
+    )
+  else
+    linters = resolve_linters()
+  end
   for i, linter in pairs(linters) do
     local ok, err = pcall(M.lint, linter, CLIENT_ID_OFFSET + i)
     if not ok then
@@ -92,10 +105,13 @@ function M.lint(linter, client_id)
   local pid_or_err
   local args = {}
   local bufnr = api.nvim_get_current_buf()
+  if type(linter) == "function" then
+    linter = linter()
+  end
   if linter.args then
     vim.list_extend(args, vim.tbl_map(eval_fn_or_id, linter.args))
   end
-  if not linter.stdin then
+  if not linter.stdin and linter.append_fname ~= false then
     table.insert(args, api.nvim_buf_get_name(bufnr))
   end
   local opts = {
@@ -110,7 +126,7 @@ function M.lint(linter, client_id)
     stderr:close()
     handle:close()
     if code ~= 0 and not linter.ignore_exitcode then
-      print('Linter exited with code', code)
+      print('Linter command', linter.cmd, 'exited with code', code)
     end
   end)
   assert(handle, 'Error running ' .. linter.cmd .. ': ' .. pid_or_err)

lua/lint/linters/compiler.lua

@@ -0,0 +1,21 @@
+local api = vim.api
+
+
+return function()
+  local errorformat = api.nvim_buf_get_option(0, 'errorformat')
+  local makeprg = api.nvim_buf_get_option(0, 'makeprg')
+  local bufname = api.nvim_buf_get_name(0)
+  local args = {
+    api.nvim_get_option('shellcmdflag'),
+    makeprg:gsub(' %%', ' ' .. bufname),
+  }
+  return {
+    cmd = vim.opt.shell:get(),
+    args = args,
+    stdin = false,
+    append_fname = false,
+    stream = 'stderr',
+    ignore_exitcode = true,
+    parser = require('lint.parser').from_errorformat(errorformat)
+  }
+end

lua/lint/parser.lua

@@ -1,6 +1,32 @@
 local M = {}
 
 
+-- Return a parse function that uses an errorformat to parse the output.
+-- See `:help errorformat`
+function M.from_errorformat(efm)
+  return function(output)
+    local lines = vim.split(output, '\n')
+    local qflist = vim.fn.getqflist({ efm = efm, lines = lines })
+    local result = {}
+    for _, item in pairs(qflist.items) do
+      if item.valid == 1 then
+        local col = item.col > 0 and item.col -1 or 0
+        local position = { line = item.lnum - 1, character = col }
+        table.insert(result, {
+          range = {
+            ['start'] = position,
+            ['end'] = position,
+          },
+          message = item.text,
+          severity = vim.lsp.protocol.DiagnosticSeverity.Error
+        })
+      end
+    end
+    return result
+  end
+end
+
+
 -- Return a parse function that uses a pattern to parse the output.
 --
 -- The first argument is a lua pattern.