Data.Tempo

Documentation

data Tempo

Musical tempo is represented as a data structure with three orthogonal components. (Generic instances are derived in order to allow later generation of instances for Aeson classes.)

Constructors

Tempo

Fields

• freq :: Rational
• time :: UTCTime
• count :: Rational

Instances

Eq Tempo

Defined in Data.Tempo

Methods

(==) :: Tempo -> Tempo -> Bool

(/=) :: Tempo -> Tempo -> Bool

Show Tempo

Defined in Data.Tempo

Methods

showsPrec :: Int -> Tempo -> ShowS

show :: Tempo -> String

showList :: [Tempo] -> ShowS

Generic Tempo

Defined in Data.Tempo

Associated Types

type Rep Tempo :: Type -> Type

Methods

from :: Tempo -> Rep Tempo x

to :: Rep Tempo x -> Tempo

type Rep Tempo

Defined in Data.Tempo

type Rep Tempo = D1 (MetaData "Tempo" "Data.Tempo" "tempi-1.0.0.0-Jg3VX53htujJiIoGiEZ7vu" False) (C1 (MetaCons "Tempo" PrefixI True) (S1 (MetaSel (Just "freq") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Rational) :*: (S1 (MetaSel (Just "time") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 UTCTime) :*: S1 (MetaSel (Just "count") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 Rational))))

origin :: Tempo -> UTCTime

The origin of a Tempo is the time at which the number of elapsed cycles/beats would have been 0.

timeToCount :: Tempo -> UTCTime -> Rational

Given a Tempo and a clock time (UTCTime), timeToCount tells us how many cycles/beats have elapsed at that time.

countToTime :: Tempo -> Rational -> UTCTime

Given a Tempo and a count of elapsed cycles/beats, countToTime tells us when that "beat" will (or would have) take(n) place.

changeTempo :: Rational -> UTCTime -> Tempo -> Tempo

Provided a new frequency and a pivot time, changeTempo modifies a given Tempo as if the frequency changed at the pivot time, with the count continuing to increase monotonically

changeTempoNow :: Rational -> Tempo -> IO Tempo

For convenience, changeTempoNow is an IO action that changes the frequency of the tempo now, ie. at the time returned by a call to getCurrentTime embedded in the action.