Evaluate each action in the structure from left to right, and collect
the results. For a version that ignores the results see
sequenceA_.
Examples
Basic usage:
For the first two examples we show sequenceA fully evaluating a a
structure and collecting the results.
>>> sequenceA [Just 1, Just 2, Just 3]
Just [1,2,3]
>>> sequenceA [Right 1, Right 2, Right 3]
Right [1,2,3]
The next two example show
Nothing and
Just will short
circuit the resulting structure if present in the input. For more
context, check the
Traversable instances for
Either and
Maybe.
>>> sequenceA [Just 1, Just 2, Just 3, Nothing]
Nothing
>>> sequenceA [Right 1, Right 2, Right 3, Left 4]
Left 4