scratch/command cf35039 2/5: Add the mode-based declare helper

[Lars Ingebrigtsen]

branch: scratch/command
commit cf350392ea6700139a74d79b18d25149360d128d
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Add the mode-based declare helper
---
 lisp/simple.el | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lisp/simple.el b/lisp/simple.el
index df106e2..ede6c6b 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -1975,6 +1975,11 @@ BUFFER."
              (buffer-local-value 'major-mode buffer)
              (command-modes symbol))))
 
+(defun completion-with-mode-p (modes buffer)
+  (apply #'provided-mode-derived-p
+         (buffer-local-value 'major-mode buffer)
+         modes))
+
 (defun completion-on-button-p (_symbol _buffer)
   "Say whether SYMBOL should be offered as a completion.
 This is true if SYMBOL is a command that's in the local map at