hunk ./Music/Theory/Tempo_Marking.hs 1
+-- | Common music notation tempo indications.
hunk ./Music/Theory/Tempo_Marking.hs 8
+-- | A tempo marking is in terms of a common music notation 'Duration'.
hunk ./Music/Theory/Tempo_Marking.hs 39
+-- | 'Fractional' variant of 'measure_duration'.
+measure_duration_f :: Fractional c => Time_Signature -> Tempo_Marking -> c
+measure_duration_f ts = fromRational . measure_duration ts