💥 Remove :feature category

:feature was a "catch-all" category. Many of its modules fit better in
other categories, so they've been moved:

- feature/debugger -> tools/debugger
- feature/evil -> editor/evil
- feature/eval -> tools/eval
- feature/lookup -> tools/lookup
- feature/snippets -> editor/snippets
- feature/file-templates -> editor/file-templates
- feature/workspaces -> ui/workspaces

More potential changes in the future:

- A new :term category for terminal emulation modules (eshell, term and
  vterm).
- A new :os category for modules dedicated to os-specific functionality.
  The :tools macos module would fit here, but so would modules for nixos
  and arch.
- A new :services category for web-service integration, like wakatime,
  twitter, elfeed, gist and pastebin services.

modules/tools/eval/autoload/repl.el

@@ -0,0 +1,102 @@
+;;; tools/eval/autoload/repl.el -*- lexical-binding: t; -*-
+
+(defvar +eval-repl-buffers (make-hash-table :test 'equal)
+  "The buffer of the last open repl.")
+
+(define-minor-mode +eval-repl-mode
+  "A minor mode for REPL buffers.")
+
+(defun +eval--ensure-in-repl-buffer (&optional command other-window-p)
+  (maphash (lambda (key buffer)
+             (unless (buffer-live-p buffer)
+               (remhash key +eval-repl-buffers)))
+           +eval-repl-buffers)
+  (let* ((project-root (doom-project-root))
+         (key (cons major-mode project-root))
+         (buffer (gethash key +eval-repl-buffers)))
+    (cl-check-type buffer (or buffer null))
+    (unless (eq buffer (current-buffer))
+      (funcall (if other-window-p #'pop-to-buffer #'switch-to-buffer)
+               (if (buffer-live-p buffer)
+                   buffer
+                 (setq buffer
+                       (save-window-excursion
+                         (if (commandp command)
+                             (call-interactively command)
+                           (funcall command))))
+                 (cond ((null buffer)
+                        (error "REPL handler %S couldn't open the REPL buffer" command))
+                       ((not (bufferp buffer))
+                        (error "REPL handler %S failed to return a buffer" command)))
+                 (with-current-buffer buffer
+                   (+eval-repl-mode +1))
+                 (puthash key buffer +eval-repl-buffers)
+                 buffer)))
+    (with-current-buffer buffer
+      (goto-char (if (and (derived-mode-p 'comint-mode)
+                          (cdr comint-last-prompt))
+                     (cdr comint-last-prompt)
+                   (point-max)))
+      buffer)))
+
+(defun +eval-open-repl (prompt-p &optional other-window-p)
+  (let ((command (cdr (assq major-mode +eval-repls))))
+    (when (or (not command) prompt-p)
+      (let* ((choices (or (cl-loop for sym being the symbols
+                                   for sym-name = (symbol-name sym)
+                                   if (string-match "^\\(?:\\+\\)?\\([^/]+\\)/open-\\(?:\\(.+\\)-\\)?repl$" sym-name)
+                                   collect
+                                   (format "%s (%s)"
+                                           (match-string-no-properties 1 sym-name)
+                                           (or (match-string-no-properties 2 sym-name) "default")))
+                          (user-error "There are no known available REPLs")))
+             (choice (or (completing-read "Open a REPL for: " choices)
+                         (user-error "Aborting")))
+             (choice-split (split-string choice " " t))
+             (module (car choice-split))
+             (repl (substring (cadr choice-split) 1 -1)))
+        (setq command
+              (intern-soft
+               (format "+%s/open-%srepl" module
+                       (if (string= repl "default")
+                           ""
+                         repl))))))
+    (unless (commandp command)
+      (error "Couldn't find a valid REPL for %s" major-mode))
+    (when (+eval--ensure-in-repl-buffer command other-window-p)
+      (when (bound-and-true-p evil-mode)
+        (call-interactively #'evil-append-line))
+      t)))
+
+;;;###autoload
+(defun +eval/open-repl-same-window (&optional arg)
+  "Opens (or reopens) the REPL associated with the current major-mode and place
+the cursor at the prompt.
+
+If ARG (universal argument), prompt for a specific REPL to open."
+  (interactive "P")
+  (+eval-open-repl arg))
+
+;;;###autoload
+(defun +eval/open-repl-other-window (&optional arg)
+  "Does `+eval/open-repl', but in a popup window.
+
+If ARG (universal argument), prompt for a specific REPL to open."
+  (interactive "P")
+  (+eval-open-repl arg t))
+
+;;;###autoload
+(defun +eval/send-region-to-repl (beg end &optional auto-execute-p)
+  "REPL must be open! Sends a selected region to it. If AUTO-EXECUTE-P, then
+execute it immediately after."
+  (interactive "r")
+  (let ((selection (buffer-substring-no-properties beg end)))
+    (unless (+eval--ensure-in-repl-buffer)
+      (error "No REPL open"))
+    (when (bound-and-true-p evil-mode)
+      (call-interactively #'evil-append-line))
+    (insert (string-trim selection))
+    (when auto-execute-p
+      ;; I don't use `comint-send-input' because different REPLs may have their
+      ;; own. So I just emulate the keypress.
+      (execute-kbd-macro (kbd "RET")))))