+(define-public (unity-if-multimeasure context dur)
+ "Given a context and a duration, return @code{1} if the duration is
+longer than the @code{measureLength} in that context, and @code{#f} otherwise.
+This supports historic use of @code{Completion_heads_engraver} to split
+@code{c1*3} into three whole notes."
+ (if (ly:moment<? (ly:context-property context 'measureLength)
+ (ly:duration-length dur))
+ 1
+ #f))
+