Add a helpful-key command

Fixes #14

2 files changed, 15 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0d10af5..a27be4a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,9 @@ Added a command `helpful-callable`, which offers both macros and
 functions. This should be a drop-in replacement for
 `describe-function`.
 
+Added a command `helpful-key`, which offers help on keybindings much
+like `describe-key`.
+
 # v0.1
 
 First release.
diff --git a/helpful.el b/helpful.el
index 26176e4..f08b1f0 100644
--- a/helpful.el
+++ b/helpful.el
@@ -701,6 +701,18 @@ For example, \"(some-func FOO &optional BAR)\"."
   (helpful-update))
 
 ;;;###autoload
+(defun helpful-key (key-sequence)
+  "Show help for interactive command bound to KEY-SEQUENCE."
+  (interactive
+   (list (read-key-sequence "Press key: ")))
+  (let ((sym (key-binding key-sequence)))
+    (unless sym
+      (user-error "No command is bound to %s"
+                  (key-description key-sequence)))
+    (switch-to-buffer (helpful--buffer sym t))
+    (helpful-update)))
+
+;;;###autoload
 (defun helpful-macro (symbol)
   "Show help for macro named SYMBOL."
   (interactive