新增用 RET 輸入目前候選、S-RET 輸入 preedit 的功能 (#220)

有些方案空白鍵不是提交，最大的例子大概是注音方案。注音方案的空白鍵是一
聲，需要用 RET 來提交輸入內容，但目前 RET 只會提交 raw input。

這個 PR 新增了一個選項，rime-return-insert-raw，non-nil 時讓 RET 輸入
raw input，否則輸入預覽內容（亦即目前選取的候選詞）。預設為 t，保留原
先的動作方式。

有測試過即使 rime-show-preedit 是 inline 也還是會輸入目前選取的候選詞。

另外，這個 PR 也新增用 Shift + RET 來輸入 preedit 的功能。注音方案下的
用途是輸入尚未轉換成漢字的注音（"1 q a S-RET" -> "ㄅ ㄆ ㄇ"），但其他
方案下應該也有用。

Author: kisaragi-hiu

rime.el

@@ -276,6 +276,13 @@ nil, don't display."
   :options '(t inline nil)
   :group 'rime)
 
+(defcustom rime-return-insert-raw t
+  "Whether hitting return commits the raw input.
+
+If nil, hitting return commits the selected candicate instead."
+  :type 'boolean
+  :group 'rime)
+
 (defcustom rime-posframe-fixed-position nil
   "Use a fixed position for posframe candidate."
   :type :boolean
@@ -777,12 +784,16 @@ By default the input-method will not handle DEL, so we need this command."
   "Commit the raw input."
   (interactive)
   (when (rime--rime-lib-module-ready-p)
-    (when-let ((input (rime-lib-get-input)))
-      (rime--clear-overlay)
-      (insert input)
-      (rime-lib-clear-composition)
-      (rime--redisplay))
-    (rime--refresh-mode-state)))
+    (if rime-return-insert-raw
+        (rime--commit
+         (rime-lib-get-input))
+      (rime--commit-preview))))
+
+(defun rime--shift-return ()
+  "Commit the preedit."
+  (interactive)
+  (when (rime--rime-lib-module-ready-p)
+    (rime--commit-preedit)))
 
 (defun rime--ascii-mode-p ()
   "If ascii-mode is enabled."
@@ -910,6 +921,30 @@ By default the input-method will not handle DEL, so we need this command."
               (string-match-p "self-insert" (symbol-name this-command)))
     (rime--clear-state)))
 
+(defun rime--commit (value)
+  "Insert VALUE, then clear state."
+  (when (and value (rime--rime-lib-module-ready-p))
+    (rime--clear-overlay)
+    (insert value)
+    (rime-lib-clear-composition)
+    (rime--redisplay)
+    (rime--refresh-mode-state)))
+
+(defun rime--commit-preview ()
+  "Commit the currently previewed text."
+  (when (rime--rime-lib-module-ready-p)
+    (rime--commit
+     (-some->> (rime-lib-get-context)
+       (alist-get 'commit-text-preview)))))
+
+(defun rime--commit-preedit ()
+  "Commit the currently previewed text."
+  (when (rime--rime-lib-module-ready-p)
+    (rime--commit
+     (-some->> (rime-lib-get-context)
+       (alist-get 'composition)
+       (alist-get 'preedit)))))
+
 (defun rime-commit1 ()
   "Commit the 1st item if exists."
   (interactive)
@@ -1051,6 +1086,8 @@ Argument NAME ignored."
     (define-key keymap (kbd "<backspace>") 'rime--backspace)
     (define-key keymap (kbd "<return>") 'rime--return)
     (define-key keymap (kbd "RET") 'rime--return)
+    (define-key keymap (kbd "S-<return>") 'rime--shift-return)
+    (define-key keymap (kbd "S-RET") 'rime--shift-return)
     (define-key keymap (kbd "<escape>") 'rime--escape)
     keymap)
   "Keymap during composition.")