Add :editor word-wrap module

Defines a new minor-mode `+word-wrap-mode` which configures
adaptive-wrap-prefix-mode and visual-line-mode for smart soft-wrapping
of code.

Evil users can toggle it with `SPC t w`.

Enable globally with `+global-word-wrap-mode`.

See the README for more details!

modules/editor/word-wrap/autoload.el

@@ -0,0 +1,76 @@
+;;; editor/word-wrap/autoload.el -*- lexical-binding: t; -*-
+
+(defvar +word-wrap--prev-adaptive-wrap-mode nil)
+(defvar +word-wrap--prev-visual-line-mode nil)
+(defvar +word-wrap--major-mode-indent-var nil)
+
+(defun +word-wrap--adjust-extra-indent-a (orig-fn beg end)
+  "Contextually adjust extra word-wrap indentation."
+  (let ((adaptive-wrap-extra-indent (+word-wrap--calc-extra-indent beg)))
+    (funcall orig-fn beg end)))
+
+(defun +word-wrap--calc-extra-indent (p)
+  "Calculate extra word-wrap indentation at point."
+  (if (not (sp-point-in-comment p))
+      (pcase +word-wrap-extra-indent
+        ('double
+         (* 2 (symbol-value +word-wrap--major-mode-indent-var)))
+        ('single
+         (symbol-value +word-wrap--major-mode-indent-var))
+        ((and (pred integerp) fixed)
+         fixed)
+        (_ 0))
+    0))
+
+;;;###autoload
+(define-minor-mode +word-wrap-mode
+  "Wrap long lines in the buffer with language-aware indentation.
+
+This mode configures `adaptive-wrap' and `visual-line-mode' to wrap long lines
+without modifying the buffer content. This is useful when dealing with legacy
+code which contains gratuitously long lines, or running emacs on your
+wrist-phone.
+
+Wrapped lines will be indented to match the preceding line. Lines which are not
+inside a comment will have additional indentation according to the configuration
+of `+word-wrap-extra-indent'."
+  :init-value nil
+  (if +word-wrap-mode
+      (progn
+        (require 'adaptive-wrap)
+        (require 'dtrt-indent) ; for dtrt-indent--search-hook-mapping
+        (require 'smartparens) ; for sp-point-in-string-or-comment
+
+        (setq-local +word-wrap--prev-adaptive-wrap-mode adaptive-wrap-prefix-mode)
+        (setq-local +word-wrap--prev-visual-line-mode visual-line-mode)
+        (setq-local +word-wrap--major-mode-indent-var
+                    (caddr (dtrt-indent--search-hook-mapping major-mode)))
+
+        (advice-add #'adaptive-wrap-fill-context-prefix :around #'+word-wrap--adjust-extra-indent-a)
+
+        (unless +word-wrap--prev-adaptive-wrap-mode
+          (adaptive-wrap-prefix-mode +1))
+        (unless +word-wrap--prev-visual-line-mode
+          (visual-line-mode +1)))
+
+    ;; disable +word-wrap-mode
+    (advice-remove #'adaptive-wrap-fill-context-prefix #'+word-wrap--adjust-extra-indent-a)
+
+    (unless +word-wrap--prev-adaptive-wrap-mode
+      (adaptive-wrap-prefix-mode -1))
+    (unless +word-wrap--prev-visual-line-mode
+      (visual-line-mode -1))))
+
+(defun +word-wrap--enable-global-mode ()
+  "Enable `+word-wrap-mode' for `+word-wrap-global-mode'.
+
+Wrapping will be automatically enabled in all modes except special modes, or
+modes explicitly listed in `+word-wrap-disabled-modes'."
+  (unless (or (eq (get major-mode 'mode-class) 'special)
+              (memq major-mode +word-wrap-disabled-modes))
+    (+word-wrap-mode +1)))
+
+;;;###autoload
+(define-globalized-minor-mode +global-word-wrap-mode
+  +word-wrap-mode
+  +word-wrap--enable-global-mode)