Music.Time.Span

Provides time spans.

Documentation

data Span

A Span represents two points in time u and v where t <= u or, equivalently, a time t and a duration d where d >= 0.

A third way of looking at Span is that it represents a time transformation where onset is translation and duration is scaling.

Instances

Eq Span

Ord Span

Show Span

Monoid Span

Semigroup Span

Delayable Span

Stretchable Span

HasOffset Span

HasOnset Span

HasDuration Span

ComonadEnv Span Note

Constructing spans

(<->) :: Time -> Time -> Span

t <-> u represents the span between t and u.

(>->) :: Time -> Duration -> Span

t >-> d represents the span between t and t .+^ d.

era :: (HasOnset a, HasOffset a) => a -> Span

Get the era (onset to offset) of a given value.

Deconstructing spans

range :: Iso' Span (Time, Time)

View a span as onset and offset.

Typically used with the ViewPatterns extension, as in

 foo (view range -> (u,v)) = ...

delta :: Iso' Span (Time, Duration)

View a span as a time and duration.

Typically used with the ViewPatterns extension, as in

 foo (view delta -> (t,d)) = ...

Span as transformation

sunit :: Span

The default span, i.e. start <-> stop.

sapp :: (Delayable a, Stretchable a) => Span -> a -> a

Apply a span transformation.

sunder :: (Delayable a, Stretchable a, Delayable b, Stretchable b) => Span -> (a -> b) -> a -> b

Apply a function under a span transformation.

sinvert :: Span -> Span

The inversion of a span.

 sinvert (sinvert s) = s
 sapp (sinvert s) . sapp s = id