feat(linter): shellcheck

README.md

@@ -100,9 +100,10 @@ Table format for custom tool:
 
 #### Linter
 
-- `clang-tidy`
-- `Pylint`
-- `rubocop`
+- [clang-tidy](https://clang.llvm.org/extra/clang-tidy/)
+- [pylint](https://github.com/PyCQA/pylint)
+- [rubocop](https://github.com/rubocop/rubocop)
+- [shellcheck](https://github.com/koalaman/shellcheck)
 
 ## Troubleshooting
 

lua/guard/tools/linter/shellcheck.lua

@@ -0,0 +1,37 @@
+local diag_fmt = require('guard.lint').diag_fmt
+return {
+  cmd = 'shellcheck',
+  args = { '--format', 'json1', '--external-sources' },
+  stdin = true,
+  output_fmt = function(result, buf)
+    local comments = vim.json.decode(result).comments
+
+    if #comments < 1 then
+      return {}
+    end
+
+    -- https://github.com/koalaman/shellcheck/blob/master/shellcheck.1.md
+    -- "Valid values in order of severity are error, warning, info and style."
+    local severities = {
+      error = 1,
+      warning = 2,
+      info = 3,
+      style = 4
+    }
+
+    local diags = {}
+
+    vim.tbl_map(function(mes)
+      diags[#diags + 1] = diag_fmt(
+        buf,
+        tonumber(mes.line) - 1,
+        tonumber(mes.column) - 1,
+        mes.message .. ' [' .. mes.code .. ']',
+        severities[mes.level] or 4,
+        'shellcheck'
+      )
+    end, comments)
+
+    return diags
+  end
+}