feat(linter): add zsh syntax checker (#62)

* feat(linter): add zsh syntax checker

* fix(ci): add luarocks bin to PATH

* fix: revert ci change

Author: barrettruth

lua/guard-collection/linter/init.lua

@@ -23,4 +23,5 @@ return {
   mypy = require('guard-collection.linter.mypy').mypy,
   mypyc = require('guard-collection.linter.mypy').mypyc,
   dmypy = require('guard-collection.linter.mypy').dmypy,
+  zsh = require('guard-collection.linter.zsh'),
 }

lua/guard-collection/linter/zsh.lua

@@ -0,0 +1,24 @@
+local lint = require('guard.lint')
+
+return {
+  fn = function(_, fname)
+    local co = assert(coroutine.running())
+    vim.system({ 'zsh', '-n', fname }, {}, function(result)
+      coroutine.resume(co, result.stderr or '')
+    end)
+    return coroutine.yield()
+  end,
+  parse = function(result, bufnr)
+    local diags = {}
+    for line in result:gmatch('[^\n]+') do
+      local lnum, msg = line:match(':(%d+): (.+)$')
+      if lnum then
+        table.insert(
+          diags,
+          lint.diag_fmt(bufnr, tonumber(lnum) - 1, 0, msg, vim.diagnostic.severity.ERROR, 'zsh')
+        )
+      end
+    end
+    return diags
+  end,
+}

test/linter/zsh_spec.lua

@@ -0,0 +1,25 @@
+describe('zsh', function()
+  it('can lint', function()
+    local helper = require('test.linter.helper')
+    local ns = helper.namespace
+    local ft = require('guard.filetype')
+    ft('zsh'):lint('zsh')
+
+    local buf, diagnostics = helper.test_with('zsh', {
+      'if true; then',
+    })
+    assert.are.same({
+      {
+        bufnr = buf,
+        col = 0,
+        end_col = 0,
+        end_lnum = 1,
+        lnum = 1,
+        message = "parse error near `\\n'",
+        namespace = ns,
+        severity = 1,
+        source = 'zsh',
+      },
+    }, diagnostics)
+  end)
+end)