From 66180dfc333ced5112c1ecfc25b9aff76bd0222c Mon Sep 17 00:00:00 2001
From: cxxxr <g23tlm@gmail.com>
Date: Mon, 4 Nov 2024 23:56:48 +0900
Subject: [PATCH] add nix-mode

---
 extensions/nix-mode/indent.lisp      | 22 +++++++++++
 extensions/nix-mode/lem-nix-mode.asd |  5 +++
 extensions/nix-mode/nix-mode.lisp    | 59 ++++++++++++++++++++++++++++
 lem.asd                              |  1 +
 4 files changed, 87 insertions(+)
 create mode 100644 extensions/nix-mode/indent.lisp
 create mode 100644 extensions/nix-mode/lem-nix-mode.asd
 create mode 100644 extensions/nix-mode/nix-mode.lisp

diff --git a/extensions/nix-mode/indent.lisp b/extensions/nix-mode/indent.lisp
new file mode 100644
index 000000000..f3fd19d54
--- /dev/null
+++ b/extensions/nix-mode/indent.lisp
@@ -0,0 +1,22 @@
+(defpackage :lem-nix-mode/indent
+  (:use :cl
+        :lem
+        :lem/language-mode)
+  (:export :beginning-of-defun
+           :end-of-defun
+           :calc-indent))
+(in-package :lem-nix-mode/indent)
+
+(defun beginning-of-defun (point n)
+  (loop :repeat n :do (search-backward-regexp point "^\\{")))
+
+(defun end-of-defun (point n)
+  (if (minusp n)
+      (beginning-of-defun point (- n))
+      (search-forward-regexp point "^\\}")))
+
+(defun calc-indent (point)
+  (with-point ((point point))
+    (let ((tab-width (variable-value 'tab-width :default point))
+          (column (point-column point)))
+      (+ column (- tab-width (rem column tab-width))))))
diff --git a/extensions/nix-mode/lem-nix-mode.asd b/extensions/nix-mode/lem-nix-mode.asd
new file mode 100644
index 000000000..9a6c9b1be
--- /dev/null
+++ b/extensions/nix-mode/lem-nix-mode.asd
@@ -0,0 +1,5 @@
+(defsystem "lem-nix-mode"
+  :depends-on ("lem")
+  :serial t
+  :components ((:file "indent")
+               (:file "nix-mode")))
diff --git a/extensions/nix-mode/nix-mode.lisp b/extensions/nix-mode/nix-mode.lisp
new file mode 100644
index 000000000..2fc3e6111
--- /dev/null
+++ b/extensions/nix-mode/nix-mode.lisp
@@ -0,0 +1,59 @@
+(defpackage :lem-nix-mode
+  (:use :cl
+        :lem
+        :lem/language-mode
+        :lem/language-mode-tools)
+  (:local-nicknames (:indent :lem-nix-mode/indent))
+  (:export :nix-mode))
+(in-package :lem-nix-mode)
+
+(defun tokens (boundary strings)
+  (let ((alternation
+          `(:alternation ,@(sort (copy-list strings) #'> :key #'length))))
+    (if boundary
+        `(:sequence ,boundary ,alternation ,boundary)
+        alternation)))
+
+(defun make-tmlanguage-nix ()
+  (let ((patterns (make-tm-patterns
+                   (make-tm-region '(:sequence "#") "$" :name 'syntax-comment-attribute)
+                   (make-tm-region '(:sequence "''")
+                                   '(:sequence "''")
+                                   :name 'syntax-string-attribute)
+                   (make-tm-match (tokens :word-boundary
+                                          '("true"
+                                            "false"
+                                            "null"))
+                                  :name 'syntax-keyword-attribute)
+                   (make-tm-string-region "''")
+                   (make-tm-string-region "\""))))
+    (make-tmlanguage :patterns patterns)))
+
+(defvar *syntax-table*
+  (let ((table (make-syntax-table
+                :space-chars '(#\space #\tab #\newline)
+                :symbol-chars '(#\_)
+                :paren-pairs '((#\( . #\))
+                               (#\{ . #\})
+                               (#\[ . #\]))
+                :string-quote-chars '(#\")
+                :block-string-pairs '(("''" . "''"))
+                :line-comment-string "#")))
+    (set-syntax-parser table (make-tmlanguage-nix))
+    table))
+
+(define-major-mode nix-mode language-mode
+    (:name "Nix"
+     :keymap *nix-mode-keymap*
+     :syntax-table *syntax-table*
+     :mode-hook *nix-mode-hook*)
+  (setf (variable-value 'enable-syntax-highlight) t
+        (variable-value 'indent-tabs-mode) nil
+        (variable-value 'tab-width) 2
+        (variable-value 'calc-indent-function) 'indent:calc-indent
+        (variable-value 'line-comment) "#"
+        (variable-value 'beginning-of-defun-function) 'indent:beginning-of-defun
+        (variable-value 'end-of-defun-function) 'indent:end-of-defun
+        ))
+
+(define-file-type ("nix") nix-mode)
diff --git a/lem.asd b/lem.asd
index 5348acaf3..ad1b01263 100644
--- a/lem.asd
+++ b/lem.asd
@@ -258,6 +258,7 @@
                "lem-documentation-mode"
                "lem-elisp-mode"
                "lem-terraform-mode"
+               "lem-nix-mode"
                "lem-markdown-mode"
                "lem-color-preview"
                "lem-lua-mode"