module: add :lang graphviz

Close: #7546
Co-authored-by: nbfalcon <nbfalcon@users.noreply.github.com>
Co-authored-by: peterhoeg <peterhoeg@users.noreply.github.com>

modules/lang/graphviz/config.el

@@ -0,0 +1,38 @@
+;;; lang/graphviz/config.el -*- lexical-binding: t; -*-
+
+(use-package! graphviz-dot-mode
+  :mode "\\.\\(?:nw\\|rack\\)diag\\'"
+  :init
+  (after! org-src
+    (add-to-list '+org-babel-mode-alist '(dot . graphviz-dot-mode))
+    (add-to-list 'org-src-lang-modes '("dot" . graphviz-dot-mode)))
+  :config
+  (set-company-backend! 'graphviz-dot-mode 'company-graphviz-dot-backend)
+  (set-formatter! 'graphviz-dot #'+graphviz-formatter :modes '(graphviz-dot-mode))
+  (set-tree-sitter-lang! 'graphviz-dot-mode 'dot)
+
+  (when (modulep! +tree-sitter)
+    (add-hook 'graphiz-dot-mode-hook #'tree-sitter!))
+
+  (after! dtrt-indent
+    (add-to-list 'dtrt-indent-hook-mapping-list '(graphviz-mode graphviz-dot-indent-width)))
+
+  (when (and (modulep! :checker syntax)
+             (not (modulep! :checker syntax +flymake)))
+    (after! flycheck
+      (flycheck-define-checker graphviz-dot
+        "A checker using graphviz dot."
+        :command ("dot")
+        :standard-input t
+        :error-patterns ((error line-start "Error: <stdin>: " (message "syntax error in line " line (* nonl)))
+                         ;; I have no idea if this can actually be printed
+                         (error line-start "Error: <stdin>: " (message)))
+        :modes graphviz-dot-mode)
+      (add-to-list 'flycheck-checkers 'graphviz-dot)))
+
+  (map! :map graphviz-dot-mode-map
+        :localleader
+        :desc "External view" :nv "e" #'graphviz-dot-view
+        :desc "Preview"       :nv "p" #'graphviz-dot-preview
+        :prefix ("t" . "toggle")
+        :desc "Preview"       :nv "p" #'+graphviz/toggle-preview))